To see the other types of publications on this topic, follow the link: Nonlinear finite element analysis.
Dissertations / Theses on the topic 'Nonlinear finite element analysis'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Nonlinear finite element analysis.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ku, Chi Ming John. "Parallel finite element analysis of nonlinear problems." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321161.
Full text
2
Supangkat, Himawan. "On finite element analysis of nonlinear consolidation." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37795.
Full text
3
Alnaas, Waled. "Nonlinear finite element analysis of quasi-brittle materials." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/93465/.
Full textAbstract:
The development of robust solution schemes for the nonlinear finite element analysis of quasi-brittle materials has been a challenging undertaking, due mainly to the stability and convergence difficulties associated with strain-softening materials. The work described in this thesis addresses this issue by proposing a new method for improving the robustness and convergence characteristics of a finite element damage model. In this method, a smooth unloading-reloading function is employed to compute an approximate tangent matrix in an incremental iterative Newton type solution procedure. The new method is named ‘the smooth unloading-reloading’ (SUR) method. A range of examples, based on a set of idealised quasi-brittle specimens, are used to assess the performance of the SUR method. The results from these example analyses show that the proposed approach is numerically robust, effective and results in considerable savings relative to solutions obtained with a reference secant model. Three acceleration approaches are also proposed in this thesis to further improve the convergence properties of the new SUR method. The first acceleration approach, named ‘the predictive-SUR method’, predicts a converged value of a damage evolution variable using an extrapolation in semi-log space. The second proposed method is designated ‘the fixing approach’, in which a damage evolution parameter is updated from the last converged step in Stage-1 iterations and then fixed in Stage-2 iterations. The third acceleration technique employs ‘a slack tolerance’ at key stages in a computation. The improvement of the convergence properties of the SUR method, when the proposed acceleration approaches are introduced, is illustrated using a series of example computations based on the analysis of a range of plain and reinforced concrete structural elements. In addition, a new element with an embedded strong discontinuity is proposed for simulating cracks in quasi-brittle structures. The new formulation is applied to quadrilateral elements and exploited to simulate mode-I, mode-II and mixed mode fracture. The interface element approach and the smeared crack approach are used as reference methods. The results from a series of examples show that the new proposed embedded strong discontinuity approach is both effective and accurate.
4
Chandra, Rajesh. "Nonlinear finite element analysis of multilayered beam-columns." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27917.
Full textAbstract:
A finite element model has been developed in this thesis for predicting strength and stiffness behavior of multilayered beam-columns. The analysis incorporates material and geometric nonlinearities in order to determine the ultimate load carrying capacity. The finite element model takes into account the continuous variability of material properties along the length of layers so that multilayered wood beam-columns can be analyzed. Transverse as well as lateral bending in combination with axial tension or compression can be considered along with different layer configurations, various support and loading conditions.
A computer program has been developed based on this formulation. Cubic beam elements have been used. Numerical integration of the virtual work equations has been carried out using Gauss quadrature. The resulting set of nonlinear equations is solved by using the Newton-Raphson scheme.
Numerical investigations have been carried out to verify the results and test the capabilities of the program.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
5
Yao, Zhong, and 姚钟. "Nonlinear finite element analysis of reinforced concrete beams." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B5090002X.
Full textAbstract:
A nonlinear finite element program to simulate the behavior of reinforced concrete (RC) members under the action of monotonic increasing loading has been developed. The nonlinear response of the RC members is mainly due to the nonlinear material characteristics including nonlinear biaxial stress-strain relations and cracking of concrete and yielding of steel reinforcement.
A constitutive model of concrete under biaxial stress state is adopted in this thesis. In this model, concrete fails and critical cracks occur when the tensile strain of concrete exceeds the limiting tensile strain. The complete stress-strain relationship of concrete under compression and tension are employed in the study to investigate the post-peak behavior of reinforced concrete members. An elaborate cracking model has been implemented which allows concrete to crack in one or two directions. The tension stiffening effect of cracked concrete is also incorporated into this model by including a descending branch in the stress-strain curve of concrete under tension. Other nonlinear effects such as crushing of concrete in compression and yielding or strain hardening of steel reinforcement are also taken into account.
A nonlinear finite element program was developed, in which the abovementioned nonlinear effects have all been included in modeling the reinforced concrete structures. The nonlinear equations of equilibrium are solved using an incremental-iterative technique performed under displacement control. The validity of the model including the confinement effect of secondary reinforcements has been examined by analyzing three reinforced concrete beams. The performance of the numerical model was assessed by comparing results with those from available experimental data.published_or_final_version
Civil Engineering
Master
Master of Philosophy
6
Ganaba, Taher H. "Nonlinear finite element analysis of plates and slabs." Thesis, University of Warwick, 1985. http://wrap.warwick.ac.uk/34590/.
Full textAbstract:
The behaviour of steel plates and reinforced concrete slabs which undergo large deflections has been investigated using the finite element method. Geometric and material nonlinearities are both considered in the study. Two computer programs have been developed for the analysis of plates and slabs. Ihe first program is for the elastic stability of plates. The elastic buckling loads obtained for plates with and without openings and under different edge loading conditions have been compared with the analytical and numerical results obtained by other investigators using different techniques of analyses. Good correlation between the results obtained and those given by others has been achieved. Improvements in the accuracy of the results and the efficiency of the analysis for plates with openings have been achieved. The second program is for the full range analysis of steel plates and reinforced concrete slabs up to collapse. The analysis can trace the load-deflection response up to collapse including snap-through behaviours. The program allows for the yielding of steel and the cracking and crushing of concrete. The modified Newton-Raphson with load control and displacement control methods is used to trace the structural response up to collapse. The line search technique has been included to improve the rate of convergence in the analysis of reinforced concrete slabs. The program has been tested against experimental and numerical results obatined by other investigators and has been shown to give good agreement. The accuracy of a number of integration rules usually adopted in nonlinear finite elecent analyses to evaluate the stress resultants from the stress distribution throughout concrete sections has been investigated. A new integration rule has been proposed for the integration of stress distributions through cracked concrete sections or cracked and crushed concrete sections.
7
McAdie, R. L. "Finite element nonlinear stability analysis of framed structures." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/21872.
Full textAbstract:
Bibliography: pages 97-98.The development of efficient and accurate finite element modelling techniques for the routine analysis of elastic-plastic stability problems in frame structures is addressed. The necessary models, solution procedure and geometric algorithm used for nonlinear stability analysis of frames are presented. An available finite element code, NOSTRUM, which had the basic algorithms necessary to carry out nonlinear analysis was used as the starting point. The Timoshenko beam/frame elements with a layered representation of the cross-section, uniaxial elasticplastic constitutive models, different integration procedures and simplified large deformation geometric assumptions incorporated into NOSTRUM are discussed in detail. Numerical examples are given to validate the algorithms implemented and to provide the experience necessary to give guidelines for the adequate choice of discretization and numerical schemes to be used in routine nonlinear stability analysis of frame structures.
8
Chan, Mun Fong. "Nonlinear finite element analysis of sheet pile interlocks." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54482.
Full textAbstract:
A finite element program is developed to depict the behavior of a sheet pile interlock connection in an axial pull test. Two types of sheet piles, PS32 and PSX32, are considered. The thumb and finger in the interlock of a sheet pile will provide three contact points for connection with another sheet pile. The problem is highly nonlinear in nature which involves large deflections and rotations, elastic-plastic material response, and a nonlinear boundary effect due to multi-contact surfaces.
The Updated Lagrangian formulation is adopted in this study. When the response is in elastic range the Updated Lagrangian with Transformation is used while the Updated Lagrangian with Jaumann stress rate is employed when the element starts to yield. An elastic-plastic with isotropic strain hardening material model is used. The yielding of an element is detected by the Von Mises yield criterion. The finite element formulation also includes a moving contact algorithm to incorporate with both geometric and material nonlinearities. Incremental potential of contact forces for a discretized system is constructed such that geometric compatibilities are maintained between contacting bodies. A method to calculate contact tractions from residual load of internal element stresses is employed. The incremental equilibrium equation is solved by a Newton-Raphson technique. Convergence criteria based on incremental displacement, incremental internal energy of the system, and the changes in contact forces can be chosen to advance or terminate the iteration process.Ph. D.
9
Jau, Jih Jih. "Geometrically nonlinear finite element analysis of space frames." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54302.
Full textAbstract:
The displacement method of the finite element is adopted. Both the updated Lagrangian formulation and total Lagrangian formulation of a three-dimensional beam element is employed for large displacement and large rotation, but small strain analysis.
A beam-column element or finite element can be used to model geometrically nonlinear behavior of space frames. The two element models are compared on the basis of their efficiency, accuracy, economy and limitations.
An iterative approach, either Newton-Raphson iteration or modified Riks/Wempner iteration, is employed to trace the nonlinear equilibrium path. The latter can be used to perform postbuckling analysis.Ph. D.
10
Lai, Zhi Cheng. "Finite element analysis of electrostatic coupled systems using geometrically nonlinear mixed assumed stress finite elements." Diss., Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-05052008-101337/.
Full text
11
Sussman, Theodore D. "On the finite element analysis of nonlinear incompressible solids." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14923.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1987.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: v.2, leaves 246-251.
by Theodore D. Sussman.
Ph.D.
12
Huang, Chiung-Yu. "Geometrically nonlinear finite element analysis of a lattice dome." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44650.
Full textAbstract:
The geometry and the finite element method modelling of a lattice dome is presented.
Linear analyses and geometrically nonlinear analyses of the dome are performed. In
addition, a buckling load prediction method is studied and extended to the multiple
load distributions.
The results obtained from linear analyses are checked against the requirements of
NDS, National Design Standard.
Master of Science
13
Spiess, Holger. "Reduction methods in finite element analysis of nonlinear structural dynamics /." Hannover : IBNM, 2006. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015469897&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full text
14
賀小崗 and Xiaogang He. "Constitutive modeling of reinforced concrete for nonlinear finite element analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31240264.
Full text
15
Davalos, Julio F. "Geometrically nonlinear finite element analysis of a glulam timber dome." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54509.
Full textAbstract:
A finite element modeling and geometrically nonlinear static analysis of glued-laminated timber domes is presented. The modeling and analysis guidelines include: the generation of the geometry, the selection of finite elements to model the components of a dome (beams, purlins, connections, and tension ring), the specification of boundary conditions, the specification of material properties, the determination of a sufficiently accurate mesh, the determination of design loads and the specification of load combinations, the application of analysis procedures to trace the complete response of the structure, and the evaluation of the response. The modeling assumptions and analysis procedures are applied to a dome model whose geometry is based on an existing glulam timber dome of 133 ft span and 18 ft rise above the tension ring. This dome consists of triangulated networks of curved southern pine glulam members connected by steel hubs. The members lie on great circles of a spherical surface of 133.3 ft radius. The dome is covered with a tongue-and-groove wood decking, which is not considered in this study. Therefore, the surface pressures are converted into member loads and then discretized into nodal concentrated loads.
A geometrically nonlinear, 3-d, 3-node, isoparametric beam element for glulam beams is formulated, and a program is developed for the analysis of rigid-jointed space frames that can trace the response of the structure by the modified Newton-Ralphson and the modified Risk-Wempner methods. The material is assumed to be continuous, homogeneous, and transversely isotropic. The material properties are assumed to be constant through the volume of the element. The transverse isotropy assumption is validated for southern pine by testing small samples in torsion. The accuracy of the modeling assumptions for southern pine glulam beams is experimentally verified by testing full-size, curved and straight, glulam beams under combined loads. The results show that the isobeam element can accurately represent the overall linear response of the beams. However, to analyze glulam domes with the program, connector elements to model the joints and a truss element to model the tension ring must be added. Therefore, the finite element program ABAQUS is used for the analysis of the dome model.
Three dead-load/snow-load combinations are considered in the analysis of the dome model. The space frame joints and the purlin-to-beam connections are modeled with 2-node isobeam elements. A 3-d, 2-node, truss element is used to model the tension ring. Three distinct analyses are considered for rigid and flexible joints: a linear analysis to check the design adequacy of the members. A linearized eigenvalue buckling prediction analysis to estimate the buckling load, which provided accurate estimates of the critical loads when rigid joints were specified. Finally, an incremental, iterative, geometrically nonlinear analysis to trace the complete response of the structure up to failure. It is shown that elastic instability, which is governed by geometric nonlinearities, is the dominant failure mode of the test dome. At the critical load, the induced element stresses remained below the proportional limit of the material. A discussion of the results is presented, and recommendations for future extensions are included.Ph. D.
16
He, Xiaogang. "Constitutive modeling of reinforced concrete for nonlinear finite element analysis /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21607473.
Full text
17
Zhang, Yixia. "Refined non-conforming linear and nonlinear finte [sic] element analysis." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22753060.
Full text
18
Kim, Wooram. "Unconventional finite element method for nonlinear analysis of beams and plates." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3003.
Full text
19
Tang, Jun 1962. "Finite element analysis of nonlinear viscoelastic membranes in relation to thermoforming." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60485.
Full textAbstract:
Thermoforming of heated polymeric sheets into three dimensional objects of various kinds, by means of pressure inflation against molding surfaces, presents a class of contact problems. This thesis develops the finite element formulations and computer programs for modelling the free and constrained inflation of thin polymer sheets in relation to thermoforming applications. In recognition of the generally time-dependent viscoelastic behaviour of polymers, and the large strains encountered in thermoforming applications, the material is modelled as non-linear viscoelastic. For this purpose the constitutive relation proposed by Christensen is adopted, assuming the relaxation function to be exponential. Most published work on nonlinear viscoelastic membranes deals with simple axisymmetric geometries, while the finite element formulations presented in this work are for both axisymmetric and nonaxisymmetric membrane inflations, including contact against constraining surfaces. Both frictionless and slipless idealizations of contact conditions are studied. The finite element solutions of free and constrained inflations of circular membranes serve as illustrative examples for the axisymmetric case, while those for elliptical membranes serve this purpose for the nonaxisymmetric case. Comparison of the finite element results with the analytical solutions obtained for some simple free and constrained inflation problems shows excellent agreement.
20
Shayanfar, Mohsen Ali. "Nonlinear finite element analysis of normal and high strength concrete structures." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40000.
Full textAbstract:
This thesis presents a new hypoelasticity model which was implemented in nonlinear finite formulation to analyze normal and high strength reinforced concrete structures under both monotonically increasing and reversed cyclic loadings. The model includes a new hypoelasticity constitutive relationship utilizing the rotations of material axis through subsequent iterations, employment of both fixed and rotating crack models, compressive strength degradation in post-cracking regime, new uniaxial stress-strain relationships for concrete under monotonically increasing and reversed cyclic loadings, accounting for mesh sensitivity, and utilizing the tensile strength degradation due to extensive internal microcracking of the concrete. The model can account for high nonlinearity of the stress-strain behaviour of concrete in the pre-peak regime, the softening behaviour of concrete in the post-peak regime, the stiffness degradation caused by the extension of microcracks during subsequent unloadings and reloadings and the irrecoverable volume dilatation at high levels of compressive load.The effect of element size on different behavioural aspects of reinforced concrete elements including the load-displacement and load-strain characteristics, crack pattern and ultimate load are discussed along with a comparison with the experimental data where available. Various analyses indicated that the length of the descending branch of the tensile stress-strain curve of concrete defined by the value of the ultimate tensile strain, $ varepsilon sb{ rm tu}$, has a significant effect on the computed results. If the value of $ varepsilon sb{ rm tu}$ is adjusted appropriately according to the element size, it can help eliminate the mesh sensitivity drawback. To adjust an appropriate value for $ varepsilon sb{ rm tu}$, two models have been used: (a) crack band model, as a function of the fracture energy, mesh size and tensile strength of concrete, and (b) a new proposed model as a function of only the element size. The analytical results obtained using the different models are compared with the experimental results; the proposed model gives good agreement. The proposed formula is very simple and can be used for both square and non-square elements.
The effect of steel reinforcement details on the general behaviour of the structure and its mode of failure, the criterion for using the rotating crack model versus the fixed crack model, and the importance of compressive strength degradation in the post-crack regime are established using detailed analysis of five shear panels tested by Vecchio and Collins (1982). The effect of a sudden drop of the stress after the tensile strength of concrete has been exceeded on the load-deflection response, the ductility ratio and the crack pattern for two high strength concrete beams are also examined. Further analyses of a squat shear wall and a shear panel are carried out to examine the reliability of the computer program HODA developed in this study for analysis of concrete structures under both monotonic and reversed cyclic loads.
Complete response of three structural walls in a low-rise building is studied under monotonically increasing loads until failure using the nonlinear finite elements program HODA. The influence of the tension-stiffening, steel strain-hardening on the load-deflection response and the ultimate load are studied for the case of the rectangular wall. The influence of smeared steel idealization and bar elements idealization on the wall response are also investigated. The ultimate loads of walls are compared with the values calculated using the current CSA Standard CAN3-A23.3-M84. (Abstract shortened by UMI.)
21
Prakash, Shruthi. "Nonlinear Finite Element Analysis of Shrinking Reinforced Concrete Slabs-on-ground." Thesis, KTH, Betongbyggnad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231361.
Full textAbstract:
Concrete slabs-on-ground are commonly used in many types of industrial floors, warehouses, highways, parking lots and buildings. Cracks and deflection of slabs are undesired events caused by differential shrinkage, which limits the service life of the slabs. Non-linear behavior of cracks and deflections, interaction of concrete and reinforcement increase the complexity in predicting the occurrence and positioning of cracks. The Eurocode 2 provides a reference for theoretical approximation for design of concrete structures. This thesis intent to investigate the crack behavior of slabs-on-ground subjected to gradient shrinkage using nonlinear finite element analysis, as implemented in the software package Atena 2D. The first part of the thesis is focused on suitable modeling techniques for predicting cracks in concrete slabs-on-ground due to gradient shrinkage. The second part is directed towards parametric studies, performed to explore the significance of varying thickness, length, concrete strength class, bond types, reinforcement content and friction coefficient. The results obtained with the Atena 2D was validated using the design software WIN-statik for calculating the maximum crack width in the context of obtaining realistic results. Finally, the WSP guide recommended parameters were tested as inputs to the model. A slab-on-ground was modeled in Atena 2D considering these as statically indeterminate structures, where both slab and grade were included and the convergence analysis performed under plane stress conditions enabling prediction of the maximum crack widths for increasing applied shrinkage loads. Parametric studies demonstrate the dependency of the slab length, showing that a smaller length reduces the crack width, since such a slab is less constrained by the sub-base. To avoid cracks in the slabs their relative thickness should not be increased above a certain thickness, instead the reinforcement content should be increased. The numerical simulation shows that different concrete strength classes give similar cracks widths. Sand as sub-base provides less crack widths for interface materials EPS, sand and gravel. Although, dry sand as interface material gives similar crack widths as EPS, it is the best to use EPS that is also used to retard the moisture diffusion from the sub-base. The numerical model developed was validated for the recommended values given by the WSP guide, which gives less crack widths and deflections. The numerical model gives less crack widths compared to the Eurocode 2, which considers only the statistically determinant problems overestimating the crack widths. The presented examples demonstrate that the developed model can accurately predict crack formation, crack behavior and vertical deflection in concrete slabs-on-ground subjected to gradient shrinkage loads.
22
Zheng, Xiahua. "NONLINEAR STRAIN RATE DEPENDENT COMPOSITE MODEL FOR EXPLICIT FINITE ELEMENT ANALYSIS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1145626022.
Full text
23
Hoffman, Rebecca M. "Nonlinear elastic-plastic analysis using the modified finite quasi-prism element /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488193665235655.
Full text
24
Huh, Jungwon. "Dynamic reliability analysis for nonlinear structures using stochastic finite element method." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/289087.
Full textAbstract:
An efficient and accurate algorithm is developed to evaluate reliability in the time domain for nonlinear structures subjected to short duration dynamic loadings, including earthquake loading. The algorithm is based on the nonlinear stochastic finite element method (SFEM). Uncertainties in the dynamic and seismic excitation, and resistance-related parameters are incorporated by modeling them as realistically as possible. The uncertainty in them is explicitly addressed. The proposed algorithm intelligently integrates the concepts of response surface method (RSM), finite element method (FEM), first-order reliability method (FORM), and an iterative linear interpolation scheme. This leads to the stochastic finite element concept. It has the potential to estimate the risk associated with any linear or nonlinear structure that can be represented by a finite element algorithm subjected to seismic loading or any short duration dynamic loadings. In the context of the finite element method, the assumed stress-based finite element algorithm is used to increase its efficiency. Two iterative response surface schemes consisting of second order polynomials (with and without cross terms) are proposed. A mixture of saturated and central composite designs is used to assure both efficiency and accuracy of the algorithm. Sensitivity analysis is used to improve the efficiency further. The unique feature of the algorithm is that it is capable of calculating risk using both serviceability and strength limit states and actual earthquake loading time histories can be used to excite structures, enabling a realistic representation of the loading condition. The uncertainty in the amplitude of the earthquake is successfully considered in the context of RSM. Uncertainty in the frequency content of an earthquake is considered indirectly by conducting a parametric study to quantify the effect of uncertainty in the frequency content of earthquakes on the overall reliability of structures. The algorithm has been extensively verified using the Monte Carlo simulation technique. The verified algorithm is used to study the reliability of structures excited by actual earthquake time histories. The results of the numerical examples show that the proposed algorithm can be used accurately and efficiently to estimate the risk for nonlinear structures subjected to short duration time-variant loadings including seismic loading.
25
Zhang, Yixia, and 張義霞. "Refined non-conforming linear and nonlinear finte [sic] element analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242704.
Full text
26
Iu, Vai-pan. "Nonlinear vibration analysis of multilayer sandwich structure by incremental finite elements /." [Hong Kong : University of Hong Kong], 1985. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12322945.
Full text
27
鍾偉昌 and Wai-cheong Chung. "Geometrically nonlinear analysis of plates using higher order finite elements." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1986. http://hub.hku.hk/bib/B31207601.
Full text
28
Chung, Wai-cheong. "Geometrically nonlinear analysis of plates using higher order finite elements /." [Hong Kong : University of Hong Kong], 1986. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12225022.
Full text
29
Sedaghati, Ramin. "Investigations in structural optimization of nonlinear problems using the finite element method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0010/NQ52772.pdf.
Full text
30
Sirichai, Seney. "Torsional properties of spur gears in mesh using nonlinear finite element analysis." Thesis, Curtin University, 1999. http://hdl.handle.net/20.500.11937/1378.
Full textAbstract:
This thesis investigates the characteristics of static torsional mesh stiffness, load sharing ratio, and transmission errors of gears in mesh with and without a localised tooth crack.Gearing is perhaps one of the most critical components in power transmission systems. The transmission error of gears in mesh is considered to be one of the main causes of gear noise and vibration. Numerous papers have been published on gear transmission error measurement and many investigations have been devoted to gear vibration analysis. There still, however, remains to be developed a general non-linear Finite Element Model capable of predicting the effect of variations of gear torsional mesh stiffness, transmission error, transmitted load and load sharing ratio. The primary purpose of this study was to develop such a model and to study the behaviour of the static torsional mesh stiffness, load sharing ratio, and transmission error over one completed cycle of the tooth mesh.The research outlined in this thesis considers the variations of the whole gear body stiffness arising from the gear body rotation due to tooth bending deflection, shearing displacement, and contact deformation. Many different positions within the meshing cycle were investigated and then compared with the results of a gear mesh having a single cracked tooth.In order to handle contact problems with the finite element method, the stiffness relationship between the two contact areas must be established. Existing Finite Element codes rely on the use of the variational approach to formulate contact problems. This can be achieved by insertion of a contact element placed in between the two contacting areas where contact occurs. For modelling of gear teeth in mesh, the penalty parameter of the contact element is user-defined and it varies through the cyclic mesh. A simple strategy of how to overcome these difficulties is also presented. Most of the previously published finite element analysis with gears has involved only partial teeth models.In an investigation of gear transmission errors using contact elements, the whole body of the gears in mesh must be modelled, because the penalty parameter of the contact elements must account for the flexibility of the entire body of the gear not just the local stiffness at the contact point.
31
Sirichai, Seney. "Torsional properties of spur gears in mesh using nonlinear finite element analysis." Curtin University of Technology, School of Mechanical Engineering, 1999. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=9473.
Full textAbstract:
This thesis investigates the characteristics of static torsional mesh stiffness, load sharing ratio, and transmission errors of gears in mesh with and without a localised tooth crack.Gearing is perhaps one of the most critical components in power transmission systems. The transmission error of gears in mesh is considered to be one of the main causes of gear noise and vibration. Numerous papers have been published on gear transmission error measurement and many investigations have been devoted to gear vibration analysis. There still, however, remains to be developed a general non-linear Finite Element Model capable of predicting the effect of variations of gear torsional mesh stiffness, transmission error, transmitted load and load sharing ratio. The primary purpose of this study was to develop such a model and to study the behaviour of the static torsional mesh stiffness, load sharing ratio, and transmission error over one completed cycle of the tooth mesh.The research outlined in this thesis considers the variations of the whole gear body stiffness arising from the gear body rotation due to tooth bending deflection, shearing displacement, and contact deformation. Many different positions within the meshing cycle were investigated and then compared with the results of a gear mesh having a single cracked tooth.In order to handle contact problems with the finite element method, the stiffness relationship between the two contact areas must be established. Existing Finite Element codes rely on the use of the variational approach to formulate contact problems. This can be achieved by insertion of a contact element placed in between the two contacting areas where contact occurs. For modelling of gear teeth in mesh, the penalty parameter of the contact element is user-defined and it varies through the cyclic mesh. A simple strategy of how to overcome these difficulties is ++also presented. Most of the previously published finite element analysis with gears has involved only partial teeth models.In an investigation of gear transmission errors using contact elements, the whole body of the gears in mesh must be modelled, because the penalty parameter of the contact elements must account for the flexibility of the entire body of the gear not just the local stiffness at the contact point.
32
Iu, Vai-pan, and 姚偉彬. "Nonlinear vibration analysis of multilayer sandwich structure by incremental finite elements." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1985. http://hub.hku.hk/bib/B31230623.
Full text
33
Li, Jian. "Three dimensional isoparametric finite element analysis with geometric and material nonlinearities." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/12165.
Full text
34
Yue, Zhihua. "Adaptive superposition of finite element meshes in linear and nonlinear dynamic analysis." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3181.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
35
Guo, Xiu Xiu. "Finite element analysis of nonlinear stochastic oscillators with Poisson white noise excitation." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2182943.
Full text
36
Czekanski, Aleksander. "Novel nonlinear finite element analysis of dynamic contact problems using variational inequalities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59014.pdf.
Full text
37
Mun, Sungho. "Nonlinear Finite Element Analysis of Pavements and Its Application to Performance Evaluation." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-07212003-145607/.
Full textAbstract:
This research documents the findings from the study of failure mechanisms of fatigue cracking in asphalt pavements using the finite element program that employs the viscoelastic continuum damage model for asphalt layer and a nonlinear elastic model for unbound layers. Both bottom-up and top-down cracks are investigated by taking several important variables into account, such as asphalt layer thickness, layer stiffnesses, pressure distribution under loading, and load levels applied on the pavement surface. The crack initiations in different pavement structures under different loading conditions are studied by monitoring a damage contour. The developed finite element code, called VECD-FEP++, employs the viscoelastic continuum damage model as the constitutive model of asphalt concrete and the universal model (or so-called Uzan-Witczak resilient modulus model) for unbound materials. The finite element analysis of various pavement-load combinations showed significantly different failure mechanisms. Details on the VECD-FEP++ and the findings are given in the following chapters.
38
Onn, Chow Chee. "Time dependent nonlinear finite element analysis of reinforced and prestressed concrete structures." Thesis, Swansea University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280043.
Full text
39
Thaker, Tariq Ali. "Experimental and nonlinear finite element analysis of double skin beam-column joints." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/16042/.
Full textAbstract:
The Double Skin Composite (DSC) or Steel-Concrete-Steel (SCS) elements (beams, slabs and columns) have been subjected to intensive studies during the last three decades. Member beam, column and slab have been studied under monotonic, cyclic and fatigue loading, and there are also a few studies on impact loading to assess the structural response of such constructions. Validating connectivity between the DSC beam and DSC columns is behind the usage of such constructional systems since all the present studies focus on individual members. The main objective of this thesis was to introduce the Double Skin Composite (DSC) beam-column joint as a new structural element. Experimental investigation and Nonlinear Finite Element Modelling (FEM) of the structural behaviour of the DSC joint subjected to monotonic and quasi-static loading was introduced. Five DSC joints have been tested to assess the efficiency of the DSC beam-column joint in its basic design and to identify the most efficient strengthening method. Further, six DSC beam-column joints were tested to study the effect of steel fibre (SF) and the effect of high-strength concrete (HSC) on the behaviour of the joint under monotonic loading and under cyclic loading. The general FE Package ABAQUS 6.10 was used to model the nonlinear behaviour of the DSC joint. The Concrete Damage Plasticity Model (CDPM) was used to model the concrete in tension and compression, and the steel elements of the composite were modelled using the elastic-plastic model. The model was validated against the experimental result and showed good agreement in predicting the maximum load and the general behaviour with a deviation of 10% or less. The examined strengthening methods showed improvement in the ultimate load capacity of between 517% and 871%. SFC and HSC provided the best performance in increasing the ultimate load and moving the location of the plastic hinge away from the face of the column. The validated FE model was used to conduct a parametric study to investigate the effect of the concrete compressive strength, shear stud connector spacing to steel plate thickness ratio, and the stud diameter to steel plate thickness ratio. The parametric study findings were in good agreement with experimental observations such as that the concrete compressive strength had a significant effect on the joint shear resistance and ultimate load.
40
William, Gergis W. "Backcalculation of pavement layers moduli using 3D nonlinear explicit finite element analysis." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=530.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains ix, 166 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 149-158).
41
Beshara, Fouad Bakheet Aboud. "Nonlinear finite element analysis of reinforced concrete structures subjected to blast loading." Thesis, Online version, 1991. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.281229.
Full text
42
Urthaler, Lapeira Yetzirah Yksya. "On simple and accurate finite element models for nonlinear bending analysis of beams and plates." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5779.
Full textAbstract:
This study is concerned with the development of simple and accurate alternative finite element models to displacement finite element models for geometrically
nonlinear bending analysis of beams and plates. First, a unified corotational beam
finite element that incorporates the kinematics of classical as well as refined beam
theories, including the Timoshenko and Reddy beam theories, is developed in a single
finite element. The governing equations are written in a "corotational" local frame
that rotates with the element and with respect to which the standard linear engineering relations between strains and internal forces are valid. The element is based
on Lagrange interpolation of the axial displacement, Hermite cubic interpolation of
the transverse displacement, and related quadratic interpolation of the rotation, and
it does not experience shear locking. The model is verified by comparisons with exact and/or approximate solutions available in the literature. Very good agreement is
found in all cases.
Next, a finite element model is developed using a mixed formulation of the first-order shear deformation theory of laminated composite plates. A p-type Lagrangian
basis is used to approximate the nodal degrees of freedom that consist of three displacements, two rotations, and three moment resultants. The geometric nonlinearity,
in the sense of the von Kõarman, is included in the plate theory. The mixed plate
element developed herein is employed in the linear and nonlinear bending analysis of a variety of layered composite rectangular plates. The effects of transverse
shear deformation, material anisotropy, and bending-stretching coupling on deflections and stresses are investigated. The predictive capability of the present model
is demonstrated by comparison with analytical, experimental, and numerical solutions available in the literature. The model provides an accurate prediction of the
global bending response of thin and moderately thick plates subjected to moderate
and moderately large rotations. The inclusion of the bending moments at the nodes
results in increased accuracy in the computation of stresses over those determined by
conventional displacement-based finite element models. The many results presented
here for geometrically nonlinear bending analysis of beams and plates should serve as
reference for future investigations.
43
Liu, G.-Q. "Nonlinear and transient finite element analysis of general reinforced concrete plates and shells." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383083.
Full textAbstract:
The present work is concerned with the development of finite element techniques for nonlinear transient dynamic analysis of reinforced concrete plates and shells. Computational models have been developed and coded, which are applied to various engineering problems under static and dynamic loading conditions. The first part of the thesis deals with some aspects of linear-elastic, geometric and material nonlinear finite element formulations of general thin and thick shell analysis under static or quasistatic loading. A generalized displacement method is proposed to overcome the 'shear locking' problem for the degenerated thick shell element when used in the context of thin shell structures. The basic concept and mathematical formulation of the generalized displacement method are detailed and its application is illustrated by numerical examples. The method is also extended to the geometrically nonlinear analysis of thin shells based on both Updated and Total Lagrangian formulation. An elasto-viscoplastic analysis of anisotropic plates and shells is developed by means of the finite element displacement method. A discrete layered approach is adopted to represent different material properties and gradual plastification through the thickness. Viscoplastic yielding is based on the Huber-Mixes criterion extended by Hill for anisotropic material and special consideration is given to the evaluation of the viscoplastic strain increment for anisotropic situations. The second part of this thesis is concerned with nonlinear dynamic transient analysis of reinforced concrete shell structures. Direct integration methods are reviewed and discussed. In particular, the general single step explicit, implicit and implicit-explicit algorithms with predictor - corrector forms are presented and corresponding stability conditions are deduced by invoking the energy method. The modelling of reinforced concrete behaviour in shell structures under fast loading conditions is considered. Both a strain rate sensitive elasto-viscoplastic model and a strain rate sensitive elasto-plastic model are presented for describing concrete nonlinearities due to multiaxial compressive or tensile yielding under dynamic loads. The models are used in conjuction with a tensile crack monitoring algorithm to trace concrete crack opening and closing. Various reinforced concrete plates and shells are analyzed and reported in detail, with the results obtained being compared with those from other sources.
44
Tongtoe, Samruam. "Failure Prediction of Spatial Wood Structures: Geometric and Material Nonlinear Finite Element Analysis." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30557.
Full textAbstract:
The purpose of this study is to investigate spatial wood structures, trace their response on equilibrium paths, identify failure modes, and predict the ultimate load. The finite element models of this study are based on the Crafts Pavilion dome (Triax) in Raleigh, North Carolina, and the Church of the Nazarene dome (Varax) in Corvallis, Oregon. Modeling considerations include 3-d beam finite elements, transverse isotropy, torsional warping, beam-decking connectors, beam-beam connectors, geometric and material nonlinearities, and the discretization of pressure loads.
The primary objective of this study is to test the hypothesis that the beam-decking connectors (B-D connectors) form the weakest link of the dome. The beam-decking connectors are represented by nonlinear springs which model the load slip behavior of nails between the beam and the decking.
The secondary objective of this study is to develop models that are sufficiently simple to use in engineering practice.Ph. D.
45
Neto, Dorival Piedade. "On the Generalized Finite Element Method in nonlinear solid mechanics analyses." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-20012014-094606/.
Full textAbstract:
The Generalized Finite Element Method (GFEM) is a numerical method based on the Partition of Unity (PU) concept and inspired on both the Partition of Unity Method (PUM) and the hp-Cloud method. According to the GFEM, the PU is provided by first-degree Lagragian interpolation functions, defined over a mesh of elements similar to the Finite Element Method (FEM) meshes. In fact, the GFEM can be considered an extension of the FEM to which enrichment functions can be applied in specific regions of the problem domain to improve the solution. This technique has been successfully employed to solve problems presenting discontinuities and singularities, like those that arise in Fracture Mechanics. However, most publications on the method are related to linear analyses. The present thesis is a contribution to the few studies of nonlinear analyses of Solid Mechanics by means of the GFEM. One of its main topics is the derivation of a segment-to-segment generalized contact element based on the mortar method. Material and kinematic nonlinear phenomena are also considered in the numerical models. An Object-Oriented design was developed for the implementation of a GFEM nonlinear analyses framework written in Python programming language. The results validated the formulation and demonstrate the gains and possible drawbacks observed for the GFEM nonlinear approach.O Método dos Elementos Finitos Generalizados (MEFG) é um método numérico baseado no conceito de partição da unidade (PU) e inspirado no Método da Partição da Unidade (MPU) e o método das Nuvens-hp. De acordo com o MEFG, a PU é obtida por meio de funções de interpolação Lagragianas de primeiro grau, definidas sobre uma rede de elementos similar àquela do Método dos Elementos Finitos (MEF). De fato, o MEFG pode ser considerado uma extensão do MEF para a qual se pode aplicar enriquecimentos em regiões específicas do domínio, buscando melhorias na solução. Esta técnica já foi aplicada com sucesso em problemas com descontinuidades e singularidades, como os originários da Mecânica da Fratura. Apesar disso, a maioria das publicações sobre o método está relacionada a análises lineares. A presente tese é uma contribuição aos poucos estudos relacionados a análises não-lineares de Mecânica dos Sólidos por meio do MEFG. Um de seus principais tópicos é o desenvolvimento de um elemento de contato generalizado do tipo segmento a segmento baseado no método mortar. Fenômenos não lineares devidos ao material e à cinemática também são considerados nos modelos numéricos. Um projeto de orientação a objetos para a implementação de uma plataforma de análises não-lineares foi desenvolvido, escrito em linguagem de programação Python. Os resultados validam a formulação e demonstram os ganhos e possíveis desvantagens da abordagem a problemas não lineares por meio do MEFG.
46
Vali, Pour Goudarzi Hamid Reza Civil & Environmental Engineering Faculty of Engineering UNSW. "Nonlinear dynamic analysis of reinforced concrete frames under extreme loadings." Publisher:University of New South Wales. Civil & Environmental Engineering, 2009. http://handle.unsw.edu.au/1959.4/43720.
Full textAbstract:
This research focuses on improvements and application of 1D finite elements for nonlinear dynamic analysis of reinforced concrete frames under extreme loadings. The concept of force interpolation is adopted for the element formulation and a solution scheme developed based on a total secant stiffness approach that provides good convergence characteristics. The geometrical nonlinearities including 2nd order P-Delta effects as well as catenary action are considered in the element formulation. It is shown that geometrical nonlinearities may have a significant effect on member (structure) response within extreme loading scenarios. In the analysis of structures subjected to extreme loadings, accurately modelling of the post peak response is vital and, in this respect, the objectivity of the solution with softening must be maintained. The softening of concrete under compression is taken into account, and the objectivity preserved, by adopting a nonlocal damage model for the compressive concrete. The capability of nonlocal flexibility-based formulation for capturing the post-peak response of reinforced concrete beam-columns is demonstrated by numerical examples. The 1D frame element model is extended for the modelling of 3D framed structures using a simplified torque-twist model that is developed to take account of interaction between normal and tangential forces at the section level. This simplified model can capture the variation of element torsional stiffness due to presence of axial force, bending moment and shear and is efficient and is shown to provide a reasonable degree of accuracy for the analysis of 3D reinforced concrete frames. The formulations and solution algorithms developed are tested for static and dynamic analysis of reinforced concrete framed structures with examples on impact analysis of beams, dynamic analysis of frames and progressive collapse assessment of frames taken from the literature. The verification shows that the formulation is very efficient and is capable of modelling of large scale framed structures, under extreme loads, quickly and with accuracy.
47
Kapoor, Hitesh. "Isogeometric Finite Element Code Development for Analysis of Composite Structures." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50567.
Full textAbstract:
This research endeavor develops Isogeometric approach for analysis of composite structures and take advantage of higher order continuity, smoothness and variation diminishing property of Nurbs basis for stress analysis of composite and sandwich beams and plates. This research also computes stress concentration factor in a composite plate with a hole.Isogeometric nonlinear/linear finite element code is developed for static and dynamic analysis of laminated composite plates. Nurbs linear, quadratic, higher-order and k-refined elements are constructed using various refinement procedures and validated with numerical testing. Nurbs post-processor for in-plane and interlaminar stress calculation in laminated composite and sandwich plates is developed. Nurbs post-processor is found to be superior than regular finite element and in good agreement with the literature. Nurbs Isgoemetric analysis is used for stress analysis of laminated composite plate with open-hole. Stress concentration factor is computed along the hole edge and good agreement is obtained with the literature. Nurbs Isogeometric finite element code for free-vibration and linear dynamics analysis of laminated composite plates also obtain good agreement with the literature.
Main highlights of the research are newly developed 9 control point linear Nurbs element, k-refined and higher-order Nurbs elements in isogeometric framework. Nurbs elements remove shear-locking and hourglass problems in thin plates in context of first-order shear deformation theory without the additional step and compute better stresses than Lagrange finite element and higher order shear deformation theory for comparatively thick plates i.e. a/h = 4. Also, Nurbs Isogeometric analysis perform well for vibration and dynamic problems and for straight and curved edge problems.
Ph. D.
48
Cervera, Miguel. "Nonlinear analysis of reinforced concrete structures using three dimensional and shell finite element models." Thesis, Swansea University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280860.
Full text
49
Weeger, Oliver [Verfasser], and Bernd [Akademischer Betreuer] Simeon. "Isogeometric Finite Element Analysis of Nonlinear Structural Vibrations / Oliver Weeger. Betreuer: Bernd Simeon." Kaiserslautern : Technische Universität Kaiserslautern, 2015. http://d-nb.info/1071547496/34.
Full text
50
Delhelay, Davinder Singh. "Nonlinear finite element analysis of the coupled thermomechanical behaviour of turbine disc assemblies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ46072.pdf.
Full text