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1
PRADHAN, Bharat. "Out of Plane response of Unreinforced Masonry infills: Comparative analysis of experimental tests for the definition of strategies of macro modelling and fragility prediction." Doctoral thesis, Università degli Studi di Palermo, 2022. https://hdl.handle.net/10447/578468.
Full textAbstract:
During an earthquake, an interaction between the in-plane and out-of-plane seismic forces occurs and the infilled frames suffer damage in both in-plane and out-of-plane directions simultaneously. Particularly, the out-of-plane collapse of unreinforced masonry infill walls is critical even for new buildings complying with the modern seismic codes, resulting in high casualties and huge economic losses. However, the out-of-plane behaviour of infill walls is yet not fully understood. This study is therefore aimed towards characterizing the out-of-plane seismic capacity of unreinforced masonry infill walls.
First of all, available out-of-plane experimental tests performed on unreinforced masonry infill walls are reviewed with a detailed comparison of the experimental results. The influence of parameters like slenderness ratio, aspect ratio, boundary conditions, openings, vertical load, in-plane damage level, the strength of masonry and plaster, and frame stiffness are evaluated, and research gaps are identified.
Based on the collected experiments, all available analytical capacity models are checked for their accuracy in the prediction of the out-of-plane capacity of unreinforced masonry infill walls. In doing so, both types of capacity models are evaluated: Type (I) for the estimation of the out-of-plane strength in the in-plane undamaged state; Type-II for the estimation of out-of-plane strength reduction factor for the in-plane damaged state. Afterwards, the best pairs of models from two groups i.e. Type I and Type II, are coupled and checked with the experimented specimens where the reference infill specimen (specimen tested in out-of-plane without prior in-plane damage) is not available. In addition, the influence of orthotropy of the infill masonry in the out-of-plane capacity predicted by the capacity models is analysed. The possibility of using the capacity models in the cases of infill-beam gap and infill with openings is also checked.
Different available macro-modelling techniques are investigated and a simple macro-element model which can simulate the behaviour of unreinforced masonry infill walls under in-plane and out-of-plane loads is developed. The model is validated with different sets of experiments. The model takes into account the decrease in out-of-plane capacity due to prior in-plane damage and is capable to capture in-plane/out-of-plane interaction effects of the seismic forces. From the correlation between the experimental and macro-model results, empirical equations are developed that can be used to calculate the stress-strain parameters required for defining the compressive behaviour of the struts. With the provided strategy, the geometrical and mechanical parameters required for the struts can be easily identified for numerical modelling of the infill wall. Using the model, in-plane and out-of-plane responses of the infill wall in lateral loads can be checked.
To enrich the information obtained from the experiments regarding the out-of-plane behaviour of infill walls, numerical experimentation is performed by using the developed macro-model covering the range of infill’s geometrical and mechanical properties. From the detailed parametric analysis, the out-of-plane strength of the infill wall is found to be largely influenced by compressive strength, slenderness ratio, aspect ratio, and more importantly by the level of in-plane damage. The decay of strength and stiffness due to prior in-plane damage is also largely governed by the strength and the slenderness ratio of the unreinforced masonry infill. Based on the numerical results, empirical equations are proposed for the evaluation of the infilled frame’s out-of-plane capacity under in-plane damaged or undamaged conditions. The reliability of the proposed equations is proved by comparisons with experimental results.
Finally, a procedure for developing the out-of-plane fragility functions is proposed by using the developed macro-model. The fragility is calculated assuming the uncertainty in the geometric and mechanical properties of infill walls instead of the uncertainty in the seismic input. The fragility is defined with respect to the position of the infill wall in a low-rise RC building. Experimental data available in the literature are used for the validation of the output. Overall, the results indicated lower vulnerability in the out-of-plane direction for infill walls without prior in-plane damage and high vulnerability when the infill wall is prior damaged in the in-plane. The proposed procedure can be extended to other types of infill walls depending on the construction technique of the site of interest, obtaining different and specific fragility curves for perming a large-scale risk analysis.During an earthquake, an interaction between the in-plane and out-of-plane seismic forces occurs and the infilled frames suffer damage in both in-plane and out-of-plane directions simultaneously. Particularly, the out-of-plane collapse of unreinforced masonry infill walls is critical even for new buildings complying with the modern seismic codes, resulting in high casualties and huge economic losses. However, the out-of-plane behaviour of infill walls is yet not fully understood. This study is therefore aimed towards characterizing the out-of-plane seismic capacity of unreinforced masonry infill walls. First of all, available out-of-plane experimental tests performed on unreinforced masonry infill walls are reviewed with a detailed comparison of the experimental results. The influence of parameters like slenderness ratio, aspect ratio, boundary conditions, openings, vertical load, in-plane damage level, the strength of masonry and plaster, and frame stiffness are evaluated, and research gaps are identified. Based on the collected experiments, all available analytical capacity models are checked for their accuracy in the prediction of the out-of-plane capacity of unreinforced masonry infill walls. In doing so, both types of capacity models are evaluated: Type (I) for the estimation of the out-of-plane strength in the in-plane undamaged state; Type-II for the estimation of out-of-plane strength reduction factor for the in-plane damaged state. Afterwards, the best pairs of models from two groups i.e. Type I and Type II, are coupled and checked with the experimented specimens where the reference infill specimen (specimen tested in out-of-plane without prior in-plane damage) is not available. In addition, the influence of orthotropy of the infill masonry in the out-of-plane capacity predicted by the capacity models is analysed. The possibility of using the capacity models in the cases of infill-beam gap and infill with openings is also checked. Different available macro-modelling techniques are investigated and a simple macro-element model which can simulate the behaviour of unreinforced masonry infill walls under in-plane and out-of-plane loads is developed. The model is validated with different sets of experiments. The model takes into account the decrease in out-of-plane capacity due to prior in-plane damage and is capable to capture in-plane/out-of-plane interaction effects of the seismic forces. From the correlation between the experimental and macro-model results, empirical equations are developed that can be used to calculate the stress-strain parameters required for defining the compressive behaviour of the struts. With the provided strategy, the geometrical and mechanical parameters required for the struts can be easily identified for numerical modelling of the infill wall. Using the model, in-plane and out-of-plane responses of the infill wall in lateral loads can be checked. To enrich the information obtained from the experiments regarding the out-of-plane behaviour of infill walls, numerical experimentation is performed by using the developed macro-model covering the range of infill’s geometrical and mechanical properties. From the detailed parametric analysis, the out-of-plane strength of the infill wall is found to be largely influenced by compressive strength, slenderness ratio, aspect ratio, and more importantly by the level of in-plane damage. The decay of strength and stiffness due to prior in-plane damage is also largely governed by the strength and the slenderness ratio of the unreinforced masonry infill. Based on the numerical results, empirical equations are proposed for the evaluation of the infilled frame’s out-of-plane capacity under in-plane damaged or undamaged conditions. The reliability of the proposed equations is proved by comparisons with experimental results. Finally, a procedure for developing the out-of-plane fragility functions is proposed by using the developed macro-model. The fragility is calculated assuming the uncertainty in the geometric and mechanical properties of infill walls instead of the uncertainty in the seismic input. The fragility is defined with respect to the position of the infill wall in a low-rise RC building. Experimental data available in the literature are used for the validation of the output. Overall, the results indicated lower vulnerability in the out-of-plane direction for infill walls without prior in-plane damage and high vulnerability when the infill wall is prior damaged in the in-plane. The proposed procedure can be extended to other types of infill walls depending on the construction technique of the site of interest, obtaining different and specific fragility curves for perming a large-scale risk analysis.
2
張滿堂 and Mun-tong Cheung. "Moire interferometry for out-of-plane displacement measurement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209154.
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Cheung, Mun-tong. "Moire interferometry for out-of-plane displacement measurement /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12757317.
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Wagih, Abdallah Abdel Hady Ahmed. "Response of composite laminates under out-of-plane loading." Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/620794.
Full textAbstract:
The objective of the thesis is to provide scaling tool predicting the response of composite structures under out-of-plane loading by testing small coupons. This global objective cannot be achieved without understanding the damage mechanisms and their sequences in composite laminates under out-of-plane loading. The objective of the thesis is achieved by considering three different sub-objectives. The first sub-objective is focusing on understanding the damage mechanisms and their sequences in composite laminates made of different ply thicknesses. The second sub-objective focuses on understanding the influence of the laminate design parameters, mismatch angle between plies and ply thickness, on the response of composite laminates under out-of-plane loading.In the third sub-objective, the contact problem of a stiff spherical indenter with a composite plate was simulated with a 2D axisymmetric model implemented on a commercial software.Finally, the scaling tool to predict the response of composite structures under out-ofplane loading is implemented in two stepsEl objectiu d’aquesta tesi és el d’aconseguir una eina d’escalat fiable per a predir la resposta d’estructures de compòsit sota càrregues fora del pla mitjançant l’assaig de petites provetes. L’objectiu s’ha assolit considerant tres sub-objectius diferents. El primer sub-objectiu es centra en comprendre els mecanismes de dany i la seva seqüència en laminats de material compost fets amb làmines de diferent gruix.El segon sub-objectiu es centra en comprendre la influència dels paràmetres de disseny dels laminats, angle de desfasament entre capes i gruix de capa, en la resposta de compòsits laminats a càrregues fora del pla.En el tercer sub-objectiu es va simular el problema del contacte entre un indentador esfèric rígid i una placa de compòsit mitjançant un model axisimètric 2D implementat en un programari comercial.Finalment, l’eina d’escalat per a la predicció de la resposta d’estructures de material compost sota càrregues fora del pla s’implementa en dos passos
5
Wang, Kai Ph D. Massachusetts Institute of Technology. "Edge fracture of AHSS sheets under out-of-plane loading followed by in-plane loading." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100151.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 193-198).
In recent years edge fracture has become a challenge in the manufacturing industry with the dramatical increase in the application of light-weight materials such as Advanced High Strength Steels (AHSS) and aluminum alloys. A premature edge cracking is observed in components with blanked/trimmed/pierced edges during the subsequent metal forming process. To understand the underlying physical mechanism and to establish a reliable CAE model, the thesis carries out a comprehensive experimental and numerical investigation on edge fracture of a commercially available DP780 steel sheet. The study reveals that it is the substantial plastic deformation introduced during the out-of-plane sheet blanking process that compromises the material ductility within the Shear Affected Zone (SAZ), and subsequently causes the edge to fracture prematurely under the in-plane edge stretching. To simulate the fracture behavior under such a complex a loading path, the fracture initiation is modeled using the concept of a scalar damage indicator that consists of two parts which are accumulated at different stages. The first one is accumulated during the sheet blanking process, referred to as pre-damage, while the second part is produced by the following metal forming. In such a modeling frame work, a corner stone is to determine the first part of pre-damage within the SAZ. This is achieved by a hybrid experimental and numerical method. Aided by microscopic examinations on cracked surfaces, the study shows that the pre-damage distribution within the SAZ follows an exponential function that drops from the critical value of unity at the edge surface to zero over the width of the SAZ. The obtained pre-damage is then introduced as the initial damage value during the following metal forming process. Based on a detail experimental characterization, a plasticity and fracture model is introduced to describe the material behavior under investigation. The model is based on the von Mises yield condition, a non-associated Hill'48 flow potential and an isotropic hardening law, together with the MMC fracture locus description with dependence on both stress triaxiality and Lode angle parameter. The proposed model successfully predict edge fracture in numerical simulation.
by Kai Wang.
Ph. D.
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Stöhr, Adriana. "Thermal textile pixels : Out-of-plane and in-plane heat transfer measurements of knitted textiles." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-22178.
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The human body possesses a highly developed range of senses that help orienting oneself in everyday life. Especially when it comes to navigating, perceiving and reacting to the world around us, people tend to rely mostly on their vision and hearing. Suffering from an impairment of either one, or both of the predominating senses means having to counterbalance this constraint. People suffering from blindness and deaf-blindness compensate their impairment mainly by relying on their haptic perception. In this case, information is usually communicated by braille or vibrotactile means. To offer another non-visual and non-audial communication concept this thesis work introduces, the thermal textile pixels. A thermal textile pixel consists of an external thermal device, able to generate hot and cold thermal impulses, and a textile interface to transmit the signal. In order to design such thermal textile pixel it was crucial to be aware of the thermal transfer occurring through and within an textile. Numerous research studies have examined the thermal properties of textiles, especially in the context of clothing comfort, thermal comfort. Nevertheless, it should be considered that as a thermal textile pixel, the textile forms part of a system, governed by many parameters. Therefore, for designing such a device it is important to be aware of the temporal and spatial resolution of the thermal transmitted signal. These characteristics are influenced by multiple textile parameters. For this purpose, a thermal study has been performed investigating in- and out-of-plane signal transmission by textiles in combination with an external thermal device. Using an external thermal device such as a Peltier element allowed to expose the specimens to heating as well as to active cooling. Different knitted structures and material combinations have been examined to gain a first impression on the behaviour of thermal pixels. It was found that thickness and density were the most influential factors for out-of-plane heat transfer. In-plane was found influenced mainly by fibre conductivity. An anisotropic behaviour was noted in-plane, as well as between in- and out-of-plane for heat transfer. Investigating active cooling signals, it was found that a significant decline of performance was noted for all specimens. Plain PA was found to be most suitable for the transmission of heat signals. But did not perform equally well during active cooling phases. Plain Shieldex was observed to perform most steady during heating and active cooling.
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deHarak, Bruno A. "HELIUM (e, 2e) COPLANAR AND OUT-OF-PLANE EXPERIMENTS." Lexington, Ky. : [University of Kentucky Libraries], 2007. http://hdl.handle.net/10225/711.
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Thesis (Ph. D.)--University of Kentucky, 2007.Title from document title page (viewed on March 31, 2008). Document formatted into pages; contains: vi, 159 p. : ill (some col.). Includes abstract and vita. Includes bibliographical references (p. 151-157).
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Chan, Cheung. "Out of plane screening and dipolar interaction in heterostructures /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202009%20CHAN.
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Stenberg, Niclas. "On the out-of-plane mechanical behaviour of paper materials." Doctoral thesis, KTH, Solid Mechanics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3425.
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This thesis deals with the through-thickness mechanicalbehaviour of paper materials. The material response undercombined normal and shear through-thickness loadings isfundamental for analysis and understanding of many end-use andconverting operations, such as folding, creasing, printing,calandering and cutting. Therefore, this thesis addressesissues of importance in product development within thepackaging and printing industries.
The objective of the thesis is to develop a constitutivemodel for paper that, in combination with appropriate in-planemodels, enables three-dimensional structural analysis using forexample the finite element method.
Constitutive modelling requires data from carefully executedexperiments. This types of data for the through-thicknessproperties of paper are not generally available in theliterature, and therefore a novel device for through-thicknesstesting of paper materials is developed. The experimentalinvestigation includes through-thickness tension andcompression testing, shear testing and testing under differentcombinations of normal and shear loadings. Furthermore, theout-of-plane Poissons ratios are examined.
An elastic-plastic constitutive model for combined normaland shear through-thickness loadings is developed. To capturethe experimental observations, a model based on nonlinearelasticity and bounding surface plasticity is proposed.
Keywords:Paper, Paperboard, Biaxial, Tension,Compression, Shear, Z-direction, Out-of-plane, Poissonsratio, Testing, Model, Bounding surface, Yield surface,Elastic, Plastic
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Willis, C. R. "Design of unreinforced masonry walls for out-of-plane loading /." Title page, abstract and table of contents only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phw7342.pdf.
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Noor-E-Khuda, Sarkar. "Studies on the out-of-plane behaviour of masonry walls." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/93197/1/Sarkar_Noor-E-Khuda_Thesis.pdf.
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The prime aim of this PhD thesis is to contribute to the current body of knowledge on the out-of-plane performance of masonry walls through systematic investigation of the key parameters and provide insight into the design clauses of Australian Masonry Standard (AS3700-2011). The research work has been carried out through numerical simulation based on a 3D layered shell element model. The model demonstrated capability to simulate various forms of new and existing masonry systems commonly constructed in Australia such as unreinforced, internally and externally reinforced, confined and dry-stack masonry. In addition, the model simultaneously simulates in-plane and out-of-plane responses.
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Tysén, Aron. "In-plane moisture variation and the effect on paper properties and out-of-plane deformation." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90433.
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For this master thesis, two methods to apply a pattern with a controlled amount of moisture to hand sheets were evaluated. The two methods evaluated were spraying and pressing. Spraying moisture onto the sheets was deemed the easiest method to control and was chosen for further studies. The sheets were sprayed with four spray times and patterns to create different moisture content variations (4.2, 8.0, 14.2 and 26.9 pp moisture content difference). The moisture patterns were designed so the sheets had either moist spots with drier surroundings or reversibly, drier spots with moist surroundings. The sprayed sheets were dried unrestrained or fully restrained to study how in-plane moisture variations could affect paper properties and out-of-plane deformation. Unrestrained drying resulted in out-of-plane deformation around the areas where moisture had been applied. Restrained drying resulted in no out-of-plane deformation but instead changes in opacity, permeance, grammage and thickness occurred. The severity of cockling and difference in paper properties after drying were found to increase with greater moisture content variation before drying. However all effects could be obtained even at the lowest moisture content variation. The resulting out-of-plane deformation varied between ±100 μm for 4.2 pp moisture content difference and ±250 μm for 14.2 pp moisture content difference
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Laporte, Catherine. "Statistical methods for out-of-plane ultrasound transducer motion estimation." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86597.
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Freehand 3D ultrasound imaging usually involves moving a conventional tracked 2D ultrasound probe over a subject and combining the images into a volume to be interpreted for medical purposes. Tracking devices can be cumbersome; thus, there is interest in inferring the trajectory of the transducer based on the images themselves. This thesis focuses on new methods for the recovery of the out-of-plane component of the transducer trajectory using the predictive relationship between the elevational decorrelation of ultrasound speckle patterns and transducer displacement. To resolve the directional ambiguities associated with this approach, combinatorial optimisation techniques and robust statistics are combined to recover non-monotonic motion and frame intersections. In order to account for the variability of the sample correlation coefficient between corresponding image patches of fully developed speckle, a new probabilistic speckle decorrelation model is developed. This model can be used to quantify the uncertainty of any displacement estimate, thereby facilitating the use of a new maximum likelihood out-of-plane trajectory estimation approach which fully exploits the information available from multiple redundant and noisy correlation measurements collected in imagery of fully developed speckle. To generalise the applicability of these methods to the case of imagery of real tissue, a new data-driven method is proposed for locally estimating elevational correlation length based on statistical features collected within the image plane. In this approach, the relationship between the image features and local elevational correlation length is learned by sparse Gaussian process regression using a training set of synthetic ultrasound image sequences. The synthetic imagery used for learning is created via a new statistical model for the spatial distribution of ultrasound scatterers which maps realisations of a 1D generalised Poisson point process to a 3D Hilbert space-filliL'échographie 3D main-libre consiste habituellement à déplacer et à mesurer le déplacement d'une sonde échographique 2D conventionnelle au-dessus d'un sujet et à créer un volume à partir des images qui sera ensuite interprété dans un but médical. Puisque les capteurs de position externes peuvent être encombrants, il y a un intérêt à calculer la trajectoire de la sonde à partir des images elles-mêmes. Cette thèse se penche sur de nouvelles méthodes pour le calcul de la composante hors-plan de la trajectoire de la sonde utilisant la relation prédictive entre la décorrélation hors-plan du speckle échographique et le déplacement de la sonde. Afin de résoudre les ambiguïtés directionnelles associées à cette approche, un nouveau cadre d'opérations est proposé. Ce cadre combine des techniques d'optimisation combinatoire et des techniques statistiques robustes pour détecter les mouvements non-monotones et les intersections entre les images. Pour tenir compte de la variabilité du coefficient de corrélation échantillonnaire entre deux portions d'images de speckle pleinement développé correspondantes, un nouveau modèle probabiliste de la décorrélation du speckle est développé. Ce modèle permet de quantifier l'incertitude associée à l'estimé d'un déplacement, facilitant ainsi l'utilisation d'une nouvelle approche de maximisation de la vraisemblance pour l'estimation de la trajectoire hors-plan qui exploite pleinement l'information rendue disponible par des mesures de corrélation multiples et redondantes acquises dans des images de speckle pleinement développé. Afin de généraliser l'applicabilité de ces méthodes au cas d'images de tissus véritables, un nouvel algorithme guidé par les données est proposé pour l'estimation de la longueur de corrélation hors-plan locale à partir d'attributs statistiques acquis à même le plan image. Dans cette approche, la relation entre les attributs de l'image et la longueur de corr
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Fan, Mingyan. "Efficient out-of-plane microphotonic fiber-to-chip coupler designs." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37263.
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Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 59).
Due to the tremendous increase of data rates in optical communication, and as a result the forthcoming reliance on photonic circuits for all-optical switching, routing and signal processing, efficient coupling of light between a nanophotonic waveguide and a fiber has become a critical and interesting issue to investigate. The objective of this thesis is to explore new strategies for efficient fiber-to-chip coupler design and to come up with design rules based on these strategies and a competent device design. Some of the previous research in the area of coupler design is reviewed, and a novel out-of-plane fiber-to-chip coupler design that is based on phase-canceling gratings is proposed. The principle of operation of this grating is explained and may be applied to other grating designs.
by Mingyan Fan.
M.Eng.and S.B.
15
Yorkston, John. "Wide angle and out-of-plane correlations in 7Li fragmentation." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/11649.
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Robazza, Brook Raymond. "Out-of-plane stability of reinforced masonry shear walls under seismic loading : in-plane reversed cyclic testing." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45238.
Full textAbstract:
Reinforced concrete block masonry shear walls (RMSWs) often constitute the principal seismic
force resisting system in masonry structures in Canada. During an earthquake, these walls
experience the combined effects of axial gravity loading and overturning moments due to inplane
lateral seismic forces. This loading precipitates out-of-plane instability when the
longitudinal reinforcement in the wall end zones is subjected to cycles of high tensile strain
followed by compression. The Canadian masonry design standard (CSA S304.1-04) [Canadian
Standard Association 2004] stipulates stringent height-to-thickness ratio limits for the seismic
design of ductile RMSWs. Experimental research and earthquake evidence have demonstrated
this failure mechanism in reinforced concrete shear walls loaded in-plane. However, similar
evidence of the mechanism occurring in RMSWs is not available. This provided motivation for
the research study described in this thesis.
The research presented here represents the second phase of a comprehensive multi-phase
research program. The first phase involved the experimental testing of full-scale reinforced
masonry (RM) column-like specimens subjected to uniaxial cyclic tension-compression loading.
The testing provided valuable insight into the out-of-plane instability as it occurs in RM. The
second phase of the research program focused primarily on the lateral reversed-cyclic
experimental testing of two full-scale, slender RMSWs with height-to-thickness ratios of 27, well
exceeding the CSA S304.2 limits. The target failure mode was an out-of-plane failure
mechanism. The results contribute unique benchmark data for the qualitative and quantitative
assessment of the factors influencing out-of-plane instability of RMSWs as well providing better
understanding of the mechanism itself. The effect of applied axial stress on out-of-plane
instability is evaluated and possible other influential design parameters are discussed.
From the results of the experimental study, it was concluded that the applied axial stress is a
critical factor in the initiation of out-of-plane instability. This factor had effects on many other
parameters, the most important of which was the development of tensile strain in the vertical
reinforcement as well as the width and distribution of cracks over the plastic hinge height. These
results indicate that the height-to-thickness ratio alone may not be an adequate factor governing
the occurrence of out-of-plane instability in RMSWs.
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Longo, Francesco. "Numerical Modelling of Unreinforced Masonry Infill Walls under Seismic Load Considering In-Plane / Out-Of-Plane Interaction." Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/368465.
Full textAbstract:
Many studies and post-earthquake investigations have recognized that masonry infill walls play a major role in the seismic response of structures. Although their effect may be beneficial in some situations, the walls are also susceptible to high levels of damage, including collapse that can be life-threatening because of the heavy debris. Despite the critical importance of infill walls for life safety, infill walls are often neglected in numerical models and analyses implemented by designers because they are traditionally considered to be non-structural elements. Moreover, the majority of experimental studies and numerical models include only the in-plane behaviour of the panels: indeed, until recently, only sophisticated micro-models incorporated the out-of-plane response of unreinforced masonry infill walls. Recently, however, researchers have started to advance proposals for simplified macro-models that are capable of modelling in-plane/out-of-plane interaction, paving the way for the consideration of the associated issues in design practice. However, very few studies have applied these models to the dynamic seismic response history analysis of realistic structures.
In this context, this thesis focuses on the numerical modelling of unreinforced masonry (URM) infill walls, with particular attention to the combined in-plane/out-of-plane response of panels in reinforced concrete (RC) frame buildings during seismic events.
In the first part of this research, existing studies for URM masonry infill walls are reviewed, with an emphasis on the out-of-plane response of the panels. Significant experimental tests, modeling strategies and post-earthquake surveys are presented, stressing the parameters that influence the behaviour of the infills. An in-depth description is dedicated to the infill wall macro-model that is adopted for the analyses performed in this work, emphasizing its capabilities and limitations. This model consists of a single diagonal formed by two beam elements representing the wall; lumped modal mass is concentrated at the midpoint node of the diagonal. In-plane axial force and out-of-plane bending of the equivalent element interact by means of two fibre sections located adjacent to the central node. User defined domains limit axial/bending strengths and in-plane/out-of-plane ultimate displacements of the wall. When the response of an element exceeds these domains, the model simulates the collapse of this infill wall by removing it from the analysis.
Next, the numerical model is calibrated in the OpenSees software framework by comparing existing experimental results with numerical outputs. The laboratory tests comprise in-plane cyclic and out-of-plane quasi-static results on 1-bay and 1-storey frame specimens with two different types of clay URM infill walls that are frequently found in Italian and other Mediterranean countries. The calibrated model is then applied to the static pushover analysis of a set of planar frames, while the wall elements are simultaneously loaded in both orthogonal directions.
The nucleus of present study is the application of the calibrated model to the dynamic response history analysis of planar RC frames. Frame dimensions, number of stories, design and infill configurations are selected to be representative of the Italian building stock. Acceleration time histories consist of a suite of a bidirectional ground motions that are scaled to be compatible with Eurocode 8 elastic spectra. Cracking and collapse of the infill walls are monitored during the analysis. The infill walls reach their ultimate displacement capacity by a combination of in-plane and out-of-plane displacements, with the out-of-plane component usually playing the dominant role. The intensity of seismic load that is required to fail the infill walls, as well as the patterns of failure, are shown to be consistent with observed damage to URM infill walls in similar buildings during recent earthquakes.
This research suggests that simplified macro-elements are suitable for design-oriented models of URM infill walls in RC framed structures, capturing the critical interaction between in-plane and out-of-plane response of the infill walls but without making the models excessively complex.
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Mansoor, Iman. "Development of hollow out-of-plane polymer microneedles using solvent casting." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/24454.
Full textAbstract:
In recent years, extensive research has been done to find innovative ways of drug delivery to replace traditional injection using hypodermic needles. Although microneedles are proposed to provide one of the most effective and convenient transdermal drug delivery methods, their expensive fabrication techniques have created a barrier for their mass fabrication and as a result, their entry to the commercial market. A novel method, based on solvent casting, is presented for inexpensive fabrication of hollow out-of-plane polymer microneedles. Microneedles are formed during a solvent evaporation process which leaves a thick polymer layer around pillars in a pre-fabricated mold. This process is fast and allows fabrication of microneedles in variety of shapes and dimensions. The effectiveness of the microneedle arrays fabricated using this process has been demonstrated through in vivo and in vitro experiments.
In order to further optimize the microneedle design, a novel experimental method based on confocal microscopy and particle image velocimetry (PIV) is presented for characterizing the flow in a thin film during solvent casting. Using this method, the impact of temperature on polymer film formation, on a vertical profile in a mold, is investigated and discussed. This method also allowed observing some important phenomena during solvent casting such as a surface counter flow. The PIV measurements show significant differences in the flow velocity fields at different temperatures that correlate with different final polymer thicknesses on the vertical wall of the mold.
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Mansoor, Iman. "Fabrication of out-of-plane microneedles for drug delivery and biosensing." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46294.
Full textAbstract:
Hollow microneedles can be used to painlessly inject drugs or extract dermal interstitial fluid for biosensing. However, their fabrication so far has been associated with costly and time-consuming steps restricting their batch production as a viable option. This thesis presents novel methods for fabricating inexpensive hollow microneedles, and investigates new methods of characterizing the drug delivery and interstitial fluid sampling using microneedles.
First, a method is presented for fabrication of hollow polymer microneedle arrays. Microneedles are formed during a solvent casting process, which leaves a polymer layer around pillars in a pre-fabricated mold. Arrays of microneedles with lengths up to 250 µm have been fabricated. The strength of the microneedles was evaluated to ensure reliable skin penetration and their suitability for drug delivery was demonstrated by injection of fluorescent beads into a skin sample.
A second fabrication method is presented for making metallic microneedles with high aspect ratios. Solvent casting was used to coat a mold with a conductive polymer composite layer, which was then used as a seed layer in a metal electrodeposition process to form 500 µm tall microneedles. Some fabrication process steps were characterized and the strength of the microneedles was evaluated. Their usefulness for drug delivery was also demonstrated by injection of fluorescent microspheres into animal skin.
Designing effective microneedles requires understanding the drug diffusion process in skin. Here, a novel method is used to characterize diffusion of a chemotherapeutic drug injected with microneedles into skin. Using confocal microscopy, the concentration distribution of the drug was measured over time and then compared to an analytical diffusion model to obtain the drug’s diffusion coefficient. Using this method, different skin storage conditions were evaluated. It was concluded that using previously frozen skin should be avoided for transdermal drug delivery studies.
Finally, using the proposed processes, hollow and solid microneedles were fabricated for sampling interstitial fluid for biosensing applications. Minimal removal of the interstitial fluid was achieved with a solid microneedle design as well as a hollow metallic microneedle array attached to a vacuum probe, while no trace of the fluid was observed when using hollow polymer microneedles.
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Aydin, Ibrahim. "Out of plane solutions of submarines in free positive buoyancy ascent." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/27195.
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This thesis analyzes the problem of motion stability of submarines in free positive buoyancy ascent under casualty conditions such as control surface jam and loss of propulsion system response. We employ fully nonlinear, coupled six degree of freedom equations of motion and we allow response to occur in combined vertical and horizontal planes. Continuation and homotopy theory techniques are utilized to trace all possible steady state solutions in six degrees of freedom, while local perturbation reveals their stability properties. Vehicle geometric properties and control surface deflections are used as primary bifurcation parameters. Regions in parameter spaces are identified where extreme sensitivity of solutions to geometric properties and hydrodynamic modeling is present
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Bazkiani, Saeed Pourfalah. "Out-of-plane retrofitting of masonry wall using engineered cementitious composites." Thesis, Heriot-Watt University, 2017. http://hdl.handle.net/10399/3299.
Full textAbstract:
The contribution of infill masonry walls to the overall behaviour of frame structures has been acknowledged through numerous published experimental and numerical investigations. Both the in-plane and out-of-plane response of such walls have a significant effect on the overall structural performance of frames and can be subjected to a range of in-plane and out-of-plane actions (e.g. wind, earthquakes, impact and blast loads) characterised by different time-histories, loading-frequencies and intensities. Infill walls are particularly vulnerable to the application of loads in the out-of-plain direction and often sustain significant damage (in the form of cracking) which can result in failure and collapse. It is interesting to note that after sustaining a certain level of damage due to the load applied in the out-of-plane direction, an infill wall can no longer contribute to the in-plane response of a frame. In an attempt to enhance the overall behaviour of infill walls, present work sets out to develop a method for improving the out-of-plain behaviour of such elements. This is achieved through the use of a thin layer of engineered cementitious composite (ECC) which is fully or partially bonded on the face of the wall which is in tension (opposite to the face on which the out-of-plane action is applied) or on both faces of the wall. For this purpose, an ECC mix is initially developed employing materials available in the UK. Its behaviour is then established experimentally under increasing loading rates and temperatures. This material is then used to strengthen a series of beam-like masonry specimens under different loading rates by conducting a series of static and dynamic 4- point bending tests. The test data obtained is then employed to develop a numerical model of the problem at hand capable of realistically predicting the experimentally established behaviour through the use of nonlinear dynamic finite element analysis. Both, experimental and numerical studies, reveal that in all cases considered the use of ECC resulted in a significant enhancement of the out-of-plain behaviour of the specimens in terms of strength, stiffness and ductility. Furthermore, the specimens with a partially bonded ECC layer performed better compared to those with a fully ECC layer. In addition, the performance of these specimens under impact load was further enhanced when adding a second layer on the other face of the specimen. Finally, a parametric numerical investigation is conducted to assess the effect of a range of parameters (associated with the boundary conditions imposed onto the specimen, the properties of the materials involved, the geometry of the specimen and loading rate) on the behaviour of the specimens.
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Herskedal, Nicholas Anthony. "Investigation of Out-of-Plane Properties of Interlocking Compressed Earth Block Walls." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/916.
Full textAbstract:
Interlocking compressed earth blocks (ICEBs) are cement stabilized soil blocks that allow for dry stacked construction. The incomplete understanding of the inelastic performance of ICEB building systems limits widespread acceptance of this structural system in earthquake prone areas. This thesis presents results from an experimental program designed to explore the behavior of ICEB walls, built according to current design practice in Indonesia and Thailand, and subjected to out-of-plane loading. A total of five reinforced and grouted ICEB walls were constructed and tested.
Results from experimentation show the current masonry design code, ACI 530, adequately predicts the yield strength of these walls. However, ACI 530 grossly over-predicts the ICEB wall stiffness. All tests showed flexural behavior and failure, except for one wall. A brittle failure was observed in one wall before reaching the predicted flexural strength, prompting a suggested maximum shear tie spacing. The testing results provide useful data for developing analytical models that predicts the seismic behavior of ICEB walls under out-of-plane loading.
A moment-curvature relationship was developed that accurately predicts the behavior of these walls in the elastic range as well as the inelastic range. By comparing the data provided by two walls of similar sizes, one including a pilaster and one without a pilaster, insight into stiffener elements was gained. Analysis of these two walls provides a limit on the length and height of ICEB walls without stiffener elements to prevent significant structural damage during a seismic event. In all, conclusions based on experimental data from ICEB out-of-plane loading tests are aimed to provide suggestions for ICEB construction in areas of high-seismicity.
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Kuzik, Marc D. "Out-of-plane cyclic behavior of masonry walls reinforced externally with GFRP." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/MQ47054.pdf.
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Bastien, Christopher J. "Response of a grooved plate subjected to out-of-plane contact loading." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46566.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (p. 345-347).
The response of a grooved plate subjected to out-of-plane contact loading is examined. The influence of selected geometric and loading parameters are investigated, as well as the effects of various boundary conditions. The response of a laminated grooved plate with a quasi -isotropic layup of [0/ + 45/ - 45/90]15s is examined and compared to the response of an isotropic structure. Finite element analysis employing two-dimensional and three-dimensional models is utilized for this investigation via ABAQUS software, a commercial finite element modeling program. The results show that the overall response of a grooved plate subjected to out-of-plane contact loading is a product of three key items: a global response due to the overall structural configuration and global aspect of the applied loading; a local response due to the removal of material to create the groove; and a local response due to the specifics of the introduction of the loading. The global response is affected by the boundary conditions due to their influence on the internal resultant loadings (moment and shear in this case) that develop within the structure. The removal of material to create the groove causes local stress concentrations via two mechanisms: the local decrease in total plate thickness beneath the groove, and the transmission of stresses occurring near the upper plate surface around the geometric discontinuity of the groove. The latter effect is analogous to that of a through-thickness hole within a plate. The local response due to the specifics of the load introduction is unaffected by the geometric and loading parameters examined, provided that finite size issues do not influence the details of the load introduction. The loading and boundary conditions also cause the groove to change overall shape, drawing together the left and right halves of the groove surface. The total thickness beneath the groove is determined to be a key parameter affecting the response of a grooved plate. Two-dimensional models are generally able to accurately simulate the response of a three-dimensional structure except within one-half plate thickness of the free surface, where three-dimensional models are necessary.
(cont.) The overall response of a laminated grooved plate is very similar to that of an isotropic structure except local to the groove surface, where the variation in contact stiffness that occurs in a laminated structure affects the local response.
by Christopher J. Bastien.
S.M.
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Jensen, Kimberly A. "Analysis and design of surface micromachined micromanipulators for out-of-plane micropositioning /." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd254.pdf.
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Velazquez-Dimas, Juan Ignacio 1960. "Out-of-plane cyclic behavior of URM walls retrofitted with fiber composites." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282734.
Full textAbstract:
The vulnerability of unreinforced masonry buildings (URM) to earthquakes is a major concern among the earthquake engineering community. One of the most dangerous failure in URM buildings is that caused by out-of-plane loading. The main objective of this study was to understand the flexural behavior of URM masonry walls retrofitted with fiber composite strips. Seven half-scale brick masonry walls were constructed with solid clay brick tied with a Type N mortar. Six specimens were constructed in single wythe and one in double wythe. The specimens were retrofitted with vertical E-glass fabric composite strips bonded with a two component epoxy resin. All walls were subjected to a standard pattern of static cyclic out-of-plane loading applied with an air-bag system. The specimens were classified according to their height to thickness ratio (h/t) i.e. short walls having h/t = 14 and slender walls having h/t = 28. The main investigated parameter was the amount of reinforcement. This varied from 0.2 to 0.75 times the corresponding balanced condition for the short walls and from 0.5 to 3.0 times the balanced condition for the slender ones. The collected experimental data consisted of; out-of-plane deflections, tensile longitudinal strains in composite strips, and rotations along the wall sides. It was found that the strength and ductility of the walls were enhanced significantly. The walls were capable to deflect a height drift of 2 to 5% and to support pressures in excess of thirty times their own weight. Although many failures occurred such as tensile of composite strips, compression of brickwork, and in-plane shear failure, the delamination process controlled the behavior of the tested specimens. The experimental results were compared with respect to predictions given by beam theory using ultimate strength and linear elastic approaches. Three main stages of behavior corresponding to the first visible bed-joint crack, the first delamination and the ultimate load were investigated. It was concluded that the ultimate strength method overestimates the flexure capacity of the walls. The best predictions were obtained using linear elastic analysis. Preliminary design recommendations are also proposed for tensile strain in the composite, maximum deflection, and maximum reinforcement ratio.
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Jensen, Kimberly A. "Analysis and Design of Surface Micromachined Micromanipulators for Out-of-Plane Micropositioning." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/230.
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This thesis introduces two ortho-planar MEMS devices that can be used to position microcomponents: the XZ Micropositioning Mechanism and the XYZ Micromanipulator. The displacement and force relationships are presented. The devices were fabricated using surface micromachining processes and the resulting mechanisms were tested. A compliant XYZ Micromanipulator was also designed to reduce backlash and binding. In addition, several other MEMS positioners were fabricated and tested: the Micropositioning Platform Mechanism (MPM), the Ortho-planar Twisting Micromechanism (OTM), and the Ortho-planar Spring Micromechanism (OSM).
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Filianina, Mariia [Verfasser]. "Electric field-induced strain control of magnetism in in-plane and out-of-plane magnetized thin films / Mariia Filianina." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2021. http://d-nb.info/1225796024/34.
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Guardigli, Sara. "Dynamic out-of-plane behaviour of Dutch cavity walls: validation of numerical models." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Find full textAbstract:
After the second world war, cavity walls became a widespread external wall type in the North Western Europe including the Netherlands. Cavity walls consist of two leaves separated by a hollow space (cavity). The leaves are commonly made by masonry bricks, blocks, and wall ties. Wall ties are used to connect the two leaves of a cavity wall and are installed during construction. The ties are meant to withstand wind pressure mostly. Recently in the north of the Netherlands induced earthquakes took place. As consequence, many cavity walls may fail due to the crisis of the ties subjected to seismic solicitations for which they were not designed.
The present work investigate numerically the behaviour of cavity masonry wall systems with or without wall ties. The models were implemented taking into account the physical and geometric nonlinearities. Both nonlinear static and dynamic analyses have been performed by means of the �nite element software DIANA.
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Lazenka, Vera, Johanna K. Jochum, Michael Lorenz, Hiwa Modarresi, Haraldur P. Gunnlaugsson, Marius Grundmann, Bael Margriet J. Van, Kristiaan Temst, and André Vantomme. "Interface induced out-of-plane magnetic anisotropy in magnetoelectric BiFeO3-BaTiO3 superlattices." American Institute of Physics, 2017. https://ul.qucosa.de/id/qucosa%3A31216.
Full textAbstract:
Room temperature magnetoelectric BiFeO3-BaTiO3 superlattices with strong out-of-plane
magnetic anisotropy have been prepared by pulsed laser deposition. We show that the out-ofplane
magnetization component increases with the increasing number of double layers.
Moreover, the magnetoelectric voltage coefficient can be tuned by varying the number of
interfaces, reaching a maximum value of 29 V/cmOe for the20×BiFeO3-BaTiO3 superlattice.
This enhancement is accompanied by a high degree of perpendicular magnetic anisotropy,
making the latter an ideal candidate for the next generation of data storage devices.
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Khajehdehi, Rouzbeh. "Non-Linear FE Analysis of RC Slabs with and without Openings Subjected to In- Plane and Out- of- Plane Loads." Thesis, Southern Illinois University at Edwardsville, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1544931.
Full textAbstract:
There are two primary methods to investigate the response of reinforced concrete (RC) structural components. Experimental testing method has been widely used to study the behavior of RC members under different loading conditions, while the results obtained have a high degree of accuracy, it is sometimes very time consuming and also can be very costly. Finite element (FE) analysis method as a numerical based solution technique, also is widely used to analyze behavior of structural components, and although the use of this method was very time consuming in several decades ago, however utilizing existing powerful software and hardware capabilities has made it easier nowadays.
An investigation is conducted on two-way RC beam-supported slabs using FE analysis technique to study their inelastic behavior when subjected to in-plane and out-of-plane loads. Two-way RC slab models were constructed for solid slab panels tested by Nakashima (1981) and the results obtained from FE analysis were compared with the experimental data.
Non-linear 3-D ANSYS models with smeared and discrete reinforcing steel were used. The obtained results from FE method indicated an acceptable agreement with experimental data. The verified FE model then was used to investigate the effect of floor openings on inelastic behavior of two-way RC slabs subjected to in-plane and out-of-plane loads. The opening was placed in the mid-region of the slab panel, where its size was varied from 6.25% to 25% of the panel area. To satisfy the strength requirements Section 13.4 of the American Concrete Institute code (ACI 318-11), additional reinforcement were placed in the slab around the opening. The results are presented and discussed.
It is observed that the failure mechanism changes in slab with larger opening where the steel yielding starts in rebars at the opening corners, and the failure damage at the ultimate load is more distributed. It is concluded that as the opening size increases, effect of out-of-plane (gravity) load on in-plane load capacity reduction of the slab decreases while the ultimate displacement at failure increases.
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Finck, David [Verfasser], and Joachim [Akademischer Betreuer] Hausmann. "In-plane- und out-of-plane Kriechen von Sheet-Molding-Compounds bei erhöhter Temperatur / David Finck ; Betreuer: Joachim Hausmann." Kaiserslautern : Technische Universität Kaiserslautern, 2020. http://d-nb.info/1225741327/34.
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Baxter, Robert Paul. "The out-of-plane behaviour of reinforced concrete masonry walls with window openings." Thesis, University of Canterbury. Department of Civil Engineering, 2001. http://hdl.handle.net/10092/2451.
Full textAbstract:
The aim of this research was to construct and test a partially grouted reinforced concrete
masonry wall with window openings under out-of-plane loading and evaluate its
behaviour. The behaviour of the wall was compared with the results of various
theoretical models, and the accuracy of these models was evaluated relative to the
experimental results.
The specimen was 9.4m long with 1.8m long return walls at each end, giving it a Cshaped
plan. Windows were sited to reduce the out-of-plane strength - a comer window
at one end and a window that sat astride the 45° yield line near the other end. 20-series
concrete blocks were used to form the wall, with D12 vertical reinforcing at 800mm
centres, giving a vertical steel ratio of 0.074%, and 2 D16 bars horizontally forming a
bond beam in the two upper masonry courses. The wall was partially grouted, with only
cells containing reinforcement filled. The steel used was the minimum required by NZS
4229: 1999, with some minor modifications. The wall was founded on a Ribraft waffle
slab flooring system.
The test specimen behaved in a ductile manner, with a highly pinched hysteresis
response. The ultimate strength of the wall was 5.8kPa at 2% interstorey drift, which is
specified in NZS 4203: 1992 as the maximum allowable structural displacement for this
type of structure. This is 40% higher than the maximum calculated ultimate limit state
loading of 3.5kPa. Load carrying capacity did not decrease at very high post-elastic
deflections. Because of this, it has been determined that the design of partially grouted
masonry walls for out-of-plane loading is governed by deflection, not strength,
requirements.
Different analysis techniques were used to calculate the response of the wall prior to
testing. Finite element modelling in ABAQUS provided a good match with experimental
data. Yield line theory was found to give a conservative value for the ultimate load. A
modification to yield line theory to model load-displacement response was proposed, with
results obtained from a simple model giving reasonably accurate results at high
deflections.
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Penner, Osmar. "Out-of-plane dynamic stability of unreinforced masonry walls connected to flexible diaphragms." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46042.
Full textAbstract:
The vulnerability of unreinforced masonry (URM) buildings to out-of-plane damage and collapse has been clearly demonstrated in past earthquakes. Given sufficient anchorage to the diaphragms (a minimum-level retrofit), a URM wall subjected to out-of-plane inertial forces will likely develop a horizontal crack at an intermediate height. This crack will cause the wall to behave as two semi-rigid bodies, which rock in the out-of-plane direction. Past studies have demonstrated that the out-of-plane stability of a URM wall connected to the diaphragms can be related to the height to thickness ratio (h/t) and the spectral acceleration at 1 s. However, treatment of the effects of diaphragm flexibility and ground motion variability on out-of-plane wall stability in studies to date has been limited.
This dissertation presents an experimental and analytical study examining the out-of-plane stability under seismic loading of URM walls connected to flexible diaphragms. In the experimental phase, five full-scale unreinforced solid clay brick wall specimens spanning one storey were subjected to earthquake ground motions using a shake table. The top and bottom of the walls were connected to the shake table through coil springs, simulating the flexibility of the diaphragms. The apparatus allowed the wall supports to undergo large absolute displacements, as well as out-of-phase top and bottom displacements, consistent with the expected performance of URM buildings with timber diaphragms. Variables examined experimentally included diaphragm stiffness and wall height.
An analytical rigid body model was validated against the experimental results, and it was demonstrated that the model was able to reproduce the observed rocking behaviour with reasonable accuracy. The validated model was used to undertake a parametric study investigating the effects of numerous parameters on out-of-plane wall stability. Ground motion variability was accounted for by using a large suite of motions. Based on the results of the modelling, an updated out-of-plane assessment procedure was proposed. The procedure, which could be incorporated into ASCE 41, provides reference curves of h/t vs. spectral acceleration at 1 s, along with correction factors for axial load, wall thickness, ground-level walls, and exposure.
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Hawkins, Guy Lawrence. "The behaviour of bonded out-of-plane joints in fibre reinforced plastic structures." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261750.
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Sayari, Arash. "Improving the out-of-plane flexural behaviour of the FRP strengthened masonry walls." Thesis, Kingston University, 2011. http://eprints.kingston.ac.uk/20335/.
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Unreinforced masonry (URM) structures have a low resistance against lateral loading and are vulnerable to earthquake and wind effects due to their low flexural capacity and relatively brittle mode of failure. Strengthening of the masonry walls against lateral loading usually aims for increasing their load bearing capacity and ductility. The application of fibre reinforced polymer (FRP) composites as externally bonded reinforcement in repairing and strengthening of masonry walls has become more attractive than the traditional methods. Determination of the flexural out-of-plane behaviour of FRP strengthened masonry walls with different types and configurations of FRP composites is the main objective of this research. Experimental program has been developed including small-scale and large-scale experiments. In addition, theoretical finite element (FE) modelling has been developed and verification of the models via comparison with, experimental results is conducted. Small-scale experiments are designed to measure the mechanical properties of masonry and mortar samples. As a result, the values of elastic modulus and compressive strength has been evaluated and used as material properties for the FE model. For large-scale experiments, seven specimens of masonry walls were constructed with clay bricks and mortar. Six samples were constructed as thin masonry walls with 1/2 brick thickness equal to 102.5 mm and one full brick thick sample was constructed with 215mm thickness. The walls are strengthened with different types and configurations of FRP materials. The specimens are subjected to uniformly distributed lateral load, applied by an airbag, on one side and over the whole surface of the wall. Theoretical FE models are developed using ANSYS software and are verified via comparison with the experimental results. Further analysis on the behaviour of FRP, strengthened walls have also been conducted. The results show that the use of FRP strengthening has increased the out-of-plane capacity of URM walls by almost 3 times and significantly improved the ductility of the walls. The comparison of the load-deflection graphs from the theoretical modelling with the corresponding results from experimental investigation shows good compliance in elastic range of loading.
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Mohamadzadeh, Milad. "Analysis of Metal Plate Connected Wood Truss Assemblies under Out-of-Plane Loads." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/50271.
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In 2012, falls from elevation in construction industry represented 36% of the total fatalities. The Occupational Safety and Health Administration requires workers to use fall protection systems where workers are 6 feet or more above a lower level. Anchors for fall protection systems attached to roof trusses may cause out-of-plane loading on these structures. Metal plate connected wood trusses (MPCWT) are not designed to carry out-of-plane loads and MPCWT performance under these loads are not evaluated in the design process.
The goal of this research is to model and analyze MPCWT assemblies under out-of-plane loads. The rotational stiffness of truss-wall connections, and truss bracing elements are included in the structural component model. Previous experimental data of fall arrest anchor loading were used for model validation. A parametric study considering loading location, joint stiffness and dimension of trusses was conducted.
The structural analog of the MPCWT assemblies were found to have first truss deflections within 4% difference, thereby the models were validated. From parametric study results, the load location was not changed the ultimate deflection in the truss assembly by maximum value of 9%. Out-of-plane joint stiffness was the parameter that caused a large difference in the deflection results, when the joists were assumed as either rigid or simple connections. The rotational stiffness of lateral and diagonal bracing should be included as model inputs for the accurate representation of experimental behavior. Truss lengths increased the deflection at the top chord of the first truss in the assembly as truss width increased.Master of Science
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Ferreira, Tiago Miguel dos Santos. "Out-of-plane seismic performance of stone masonry walls: experimental and analytical assessment." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14079.
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Doutoramento em Engenharia CivilThis PhD thesis is focused on the characterisation of the out-of-plane seismic performance of stone masonry walls, where the development of an innovative fragility-based approach, founded on solid experimental outputs, analytical formulation and post-earthquake damage observation, was outlined as main objective. In order to achieve it, two groups of specific objectives were distinguished in function of the genesis of the work, and are discussed throughout the seven chapters that compose this document. The first chapter presents a brief introduction to the main topic of the work, the description of the general and specific objectives to be achieved and each one of the tasks performed to fulfil them. Chapter 2 presents a compact state-of-art review wherein the principal methodologies proposed to assess the out-of-plane behaviour of unreinforced masonry structures are presented and discussed. The experimental part of this research begins in the third chapter, where an in situ experimental campaign, performed on three masonry wall piers of an existing building, is presented. Chapter 4 aims at describing an experimental program conducted in laboratory environment to characterise the out-of-plane behaviour of unreinforced masonry piers. In the scope of this experimental campaign, six full-scale unreinforced regular stone masonry walls were tested resorting to two different loading techniques. Getting into the analytical part of the work, Chapter 5 presents a simplified analytical approach for the description of the out-of-plane seismic performance of unreinforced regular stone masonry wall, from an overturning moment-rotation relationship and Chapter 6 is focused on the calibration of a seismic vulnerability method, on the basis of fragility results constructed from damage limit-states obtained resorting to the analytical approach proposed in the fifth chapter. Finally, an overall synopsis of the work, the most relevant results and conclusions achieved and some future research lines are presented and discussed in Chapter 7.
Esta tese de doutoramento foca-se na caraterização do desempenho sísmico para fora do plano de paredes de alvenaria de pedra, através do desenvolvimento de uma nova metodologia baseada na fragilidade destes elementos, assente em observação experimental, formulação analítica e observação de danos pós-sismo. De forma a atingir este objetivo, definem e discutem-se neste documento dois grupos distintos de objetivos em função da génese experimental ou analítica dos trabalhos. Assim, no primeiro capítulo apresenta-se uma breve introdução ao tópico principal do trabalho e discutemse objetivos gerais e específicos a atingir em cada uma das tarefas definidas. O Capítulo 2 apresenta um estado de arte exaustivo, onde as principais metodologias propostas na bibliografia para avaliar o comportamento sísmico de estruturas de alvenaria de pedra não reforçada, são apresentadas e discutidas. A parte experimental deste trabalho inicia-se no capítulo terceiro, com a apresentação de uma campanha experimental in situ conduzida num edifício existente, localizado na ilha do Faial, Açores, e onde foram ensaiadas três paredes de alvenaria com condições de reforço distintas. O Capítulo 4 descreve um trabalho experimental conduzido em ambiente laboratorial, com o objetivo de caracterizar o comportamento para fora do plano de nembos de parede. No âmbito desta campanha experimental, construíram-se e testaramse seis nembos de parede em alvenaria de pedra regular não reforçada, com recurso a duas técnicas de ensaio distintas. Entrando no parte analítica do trabalho, o Capítulo 5 apresenta uma metodologia analítica capaz de descrever de forma simplificada a resposta sísmica para fora do plano de paredes de alvenaria de pedra regular, através de uma relação de momento fletor-rotação. O Capítulo 6 é dedicado à calibração de uma metodologia de avaliação da vulnerabilidade sísmica, com base em resultados de fragilidade obtidos através de estados limite de dano definidos através da metodologia analítica proposta no Capítulo 5. Finalmente, no sétimo capítulo apresenta-se a síntese geral do trabalho desenvolvido, discutem-se os principais resultados e conclusões obtidas e desvendam-se algumas linhas de investigação futura.
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Diehl, Michael S. "Design and Fabrication of Out-of-Plane Silicon Microneedles with Integrated Hydrophobic Microchannels." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2074.pdf.
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Summitt, Chris, Sunglin Wang, Soha Namnabat, Lee Johnson, Tom Milster, and Yuzuru Takashima. "Fast fabrication of polymer out-of-plane optical coupler by gray-scale lithography." OPTICAL SOC AMER, 2017. http://hdl.handle.net/10150/625707.
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We report a fabrication process of a polymer, and mirror-based out-of-plane optical coupler. In the process, a pre-formed mirror blank made of a buffer coat material is re-exposed by a laser direct writing tool with low numerical aperture of 0.1. The fabrication process is inherently fast because of the low numerical aperture (NA) process. The surface figure of the mirror is controlled under 0.04 waves in root-mean-square (RMS) at 1.55 mu m wavelength, with mirror angle of 45 +/- 1 degrees. Nominal insertion loss of 8.5dB of the mirror-based coupler was confirmed with polymer waveguides fabricated simultaneously. (C) 2017 Optical Society of America
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Williams, Joseph Louis. "Fatigue of Masonry Walls with CFRP Applied Externally for Out-of-Plane Loads." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/153.
Full textAbstract:
This master’s thesis presents an investigation on the effects of fatigue on fiber- reinforced polymers (FRP) when applied to masonry walls subjected to out-of-plane loading. The project aims to provide further research and add to the general testing database of FRP enhanced masonry. An introduction to the problems and solutions associated with unreinforced masonry is discussed along with a literature review on previous testing done in the field of FRP enhanced masonry. The investigation on the effects of fatigue on FRP when applied to masonry walls subjected to out-of-plane loading is performed through experimental testing. A total of four wall specimens (6 ft x 4 ft x 8 in) were constructed. One of the specimens was left unreinforced and used as a baseline for testing while the remaining three specimens were reinforced with carbon fiber reinforced polymer (CFRP) strips designed to take the out-of-plane loads capable of creating the cracking moment in the unreinforced wall. The material testing, construction of the test specimens, and CFRP application are all presented in this thesis.
With the use of an oscillating shake table to generate the out-of-plane loading, the walls were fixed at the base and cantilevered from the shake table. By determining the frequency and amplitude that generated the cracking moment in the baseline unreinforced wall, the remaining three CFRP reinforced walls were tested at the same frequency and amplitude. The results from the testing of the three CFRP reinforced walls are presented along with time histories showing the shake table displacement and wall’s tip displacement versus time. In general, fatigue of masonry walls reinforced with CFRP strips can be managed as long as the out-of-plane reinforcement has sufficient strength and development length. Additional findings were made as a result from the testing. The development length of a vertical CFRP strip can be increased by adding a horizontal CFRP strips near the critical section and surface damage to CFRP may have severe consequences.
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Tomasino, Alfred P. "The effects of porosity on the out-of-plane tensile strength of laminated composites." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53192.
Full textAbstract:
The objective of this study was to investigate the out-of-plane tensile strength of graphite/epoxy laminates as a function of porosity. An experimental test program was designed to apply tension to the faces of circular graphite/epoxy specimens in a direction perpendicular to the laminate mid-plane. The specimens were removed from the webs of angle sections fabricated by Lockheed Georgia Company using (AS4/1806 and AS4/3501-6 graphite/epoxy material systems with a stacking sequence of (±45/90₂/ ±45/0₂)S or (±45/0₂/ +̅ 45/90₂)S. The specimen porosities were the result of four distinct processing methods: a baseline hand lay-up, low pressure cure-cycle, a solvent wipe of pre-preg to remove resin, and the addition of water between pre-pregs. The experimental results have shown a significant reduction in the out-of-plane tensile strength as a function of increasing void content.
The volume fraction of pores, pore geometry, size, and orientation were determined for a representative number of specimens by metallography and optical analysis methods. This data was combined with the out-of-plane tensile data and used in the theoretical model, prepared by Brown et al, to predict the out-of-plane strength as a function of porosity. The predicted strength values compared very well with the experimental data when the pores were found to be uniformly distributed throughout the laminate.Master of Science
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Stiller, Markus, Jose Barzola-Quiquia, Pablo Esquinazi, Daniel Spemann, Jan Meijer, Michael Lorenz, and Marius Grundmann. "Strong out-of-plane magnetic anisotropy in ion irradiated anatase TiO2 thin films." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-216180.
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The temperature and field dependence of the magnetization of epitaxial, undoped anatase TiO2 thin films on SrTiO3 substrates was investigated. Low-energy ion irradiation was used to modify the surface of the films within a few nanometers, yet with high enough energy to produce oxygen and titanium vacancies. The as-prepared thin film shows ferromagnetism which increases after irradiation with low-energy
ions. An optimal and clear magnetic anisotropy was observed after the first irradiation, opposite to the expected form anisotropy. Taking into account the experimental parameters, titanium vacancies as di-Frenkel pairs appear to be responsible for the enhanced ferromagnetism and the strong anisotropy observed in our films. The magnetic impurities concentrations was measured by particle-induced X-ray emission with ppm resolution. They are ruled out as a source of the observed ferromagnetism before and after irradiation.
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Roman, Humberto Ramos. "Out-of-plane shear behaviour of brickwork joints subjected to non-uniform compressive stress." Thesis, University of Sheffield, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385713.
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Misselbrook, Paul. "Novel manufacture of out-of-plane optical interconnects to enable low cost OECB substrates." Thesis, Loughborough University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431689.
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Iqbal, Jaffar S. "Response of grooved composite laminates to out-of-plane contact loading via numerical models." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68409.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 303-305).
The response of grooved composite laminates to out-of-plane contact loading is examined using numerical modeling through the consideration of contact pressure and stresses within the laminate, with particular focus on the area local to the groove. Finite element analysis is employed via ABAQUS, a commercial finite element modeling software. The indentor is modeled as a rigid body, and the validity of this approximation is assessed through comparison with a deformable, linear elastic indentor. The influence of ply angle is investigated through consideration of a family of [+/-[theta]/0]13s laminates for values of [theta] of 15°, 30°, 45°, and 60°, along with a quasiisotropic [+/-45/0/90]10s and a crossply [0/90]20s configuration, all using T700/2510 graphite/epoxy. The linearity of the response is investigated, and two loading configurations are studied and compared: a two-dimensional, cylinder-loaded configuration, and a three-dimensional, sphere-loaded configuration. Results show that the Hertzian contact model for isotropic bodies cannot be used to determine contact pressure due to an inability of that model to analytically determine the appropriate contact length. The basic form of the contact pressure curve is similar to the Hertzian model, but with significant local variations superposed due to stiffness variation, particularly in the longitudinal direction, due to ply orientation angle. Thus, if the contact length is supplied, the Hertzian model can be a valid overall approximation. Total vertical load magnitude is determined to be a primary factor in the response, as it determines contact length, and thus the distribution of contact pressure and the form of the stress field. The response is found to vary with significant nonlinearity with respect to applied load due to the relationship with contact length. The rigid body approximation of the steel indentor is deemed sufficiently accurate to capture the overall behavior, due to the high difference in stiffness between the steel indentor and the through-thickness stiffness of the composite. There is significant variation between the two-dimensional models and the three-dimensional models, particularly in determining the magnitude of the response. However, the two-dimensional model is sufficient to observe trends, and could be of use in preliminary design and analysis, although the full three-dimensional model is required to accurately determine the response in the final analysis, largely due to important issues of variation along the groove. In general, stress behavior is dependent on the laminate and the particular stress, with stress fields between laminates showing some similar trends, but also high variability depending on the composition of the laminate.
by Jaffar S. Iqbal.
S.M.
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Tsai, Yu-Hsuan, and 蔡宇軒. "In-Plane and Out-of-Plane Color Face Detection." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/2e46z5.
Full textAbstract:
碩士國立臺灣大學
電信工程學研究所
105
Face detection plays an important role in many computer vision applications and has drawn significant research attention nowadays. The objective of face detection is to analyze whether the image contains face or not, and if it does, output the location of the bounding box for each face. In recent years, many researches attempt to extend the well-established Viola & Jones (Adaboost) face detection algorithm to suitable for multi-view face detection. Until now, it is a challenge to detect in-plane, rotated, and out-of-plane face simultaneously. In this thesis, a very robust multi-view face detection algorithm is proposed. Although it is essentially a frontal face detector, it can well detect rotated, in-plane, and out-of-plane face without rotated training faces. First, several techniques, including the skin filter and entropy rate superpixel (ERS) are applied to obtain face candidate regions. Then, angle compensation and refinement are applied to improve the accuracy of face detection in in-plane case. Moreover, to find the out-of-plane face, one can apply the symmetry extension technique, i.e., extending the face candidate with its flipping version to create a face that is similar to the frontal one. With it, even if there are no training data for out-of-plane face, one can successfully detect the face in the out-of-plane case. Simulations on the FEI, Pointing''04, Bao, Group, Utrecht, and our dataset show that the proposed algorithm is effective and outperforms state-of-the-art face detection approaches.
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陳崇原. "Out-of-plane Vibrations of Nonuniform Curved beams." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/54304692226911032128.
Full textAbstract:
碩士國立成功大學
機械工程學系
88
In the present study , the governing equations and the associated boundary conditions for the out-of-plane non-uniform circular beams and general elastic end restraints , are derived via the Hamilton's principle. Four physical parameters are introduced to simplify the analysis and the explicit relations between the torsional displacement and the flexural displacement for out-of plane direction . With these explicit relations, the two coupled governing characteristic differential equations can be decoupled and reduced to two sixth-order ordinary differential equations with variable coefficients in the out-of-plane flexural displacement and the torsional displacement, respectively. The derived explicit relations can also be used to reduce the difficulty in experimental measurement. Finally , several limiting cases are examined and the limiting procedures are revealed.
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Lo, Chiungcheng, and 羅炯成. "The Study of a Novel Out-of-plane." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/48513471421980999387.
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碩士國立清華大學
動力機械工程學系
88
Out-of-plane electrothermal actuators have been applied to a variety of fields. Among them, the actuators whose driving method is bi-metal effect have the advantage of simple fabrication process and are thus most commonly used. However, such an actuator experiences a shear force at the interface of different materials, while actuated. Delamination con-sequently takes place and therefore decreases its life time. In attempt to overcome the drawback inherent in a bi-metal actuator, a novel bi-directional out-of-plane electrothermal actuator of single material is presented. The presented actuator comprises three beams of two different cross-sectional areas. While a current is applied, different beams would have different deflection, which results in the out-of-plane motion. Additionally, by different methods of applying current, bi-directional actuation would be carried out. The feasibility of the presented design was demonstrated in light of finite element analysis and experimental results. The potential application lies in microrelays, variable capacitors, and optical scanning system.
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Tsai, Chang-Lung, and 蔡昌龍. "Design of an out-of-plane motion mechanism." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/13868278024312638177.
Full textAbstract:
碩士國立中興大學
精密工程學系所
102
This research developed a design method of an out-of-plane motion mechanism. The characteristics of buckling of a beam structure are exploited for design of the structure. This research proposes an optimization design approach which combines finite element analysis and a genetic algorithm. Quick design and assessment of the motion mechanism can be achieved. A prototype of a designed mechanism is fabricated. Experimental results show that this mechanism can effectively convert in-plane motion to out-of-plane motion. The displacement amplification of out-of-plane motion to in-plane motion of the mechanism is nearly six.