Academic literature on the topic 'Twisting moment'
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Journal articles on the topic "Twisting moment"
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Lau, John H. "Bending and Twisting of 60Sn40Pb Solder Interconnects With Creep." Journal of Electronic Packaging 116, no. 2 (June 1, 1994): 154–57. http://dx.doi.org/10.1115/1.2905504.
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An exact analysis is presented for the creep deformation of a thin-walled circular solder cylinder under the actions of bending and twisting moments. Dimensionless interaction curves and charts which relate the variables, interconnect geometry, solder material properties, bending moment, twisting moment, curvature rate, and twist rate are also provided for engineering practice convenience.
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Webb, George, Kanyakon Kosinanonth, Tushar Chaudhari, Saeid Alizadeh, and Gregory A. MacRae. "Column Moment Demands from Orthogonal Beam Twisting." Key Engineering Materials 763 (February 2018): 259–69. http://dx.doi.org/10.4028/www.scientific.net/kem.763.259.
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Beam column joint subassemblies in steel moment frames often have simply-supported gravity beams framing into the joint in the perpendicular direction. When these subassemblies undergo lateral displacement, moments enter the column from the beams. Some of these moments are directly applied from the in-plane beam and slab stresses as they contact the column, and additional moments occur as the slab causes the perpendicular simply supported beams to twist. In most design codes around the world, no explicit consideration of these moments is performed even though they may increase the likelihood of column yielding and a soft-storey mechanism. This paper quantifies the magnitude of these perpendicular beam twisting moments in typical subassemblies using inelastic finite element analysis. It is shown that for beam-column-joint-slab subassemblies where the primary and secondary beams are fully welded to the column, the addition of slab effects significantly increases the total stiffness and strength of the composite frame structure. In addition to this, it is also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 2% for an imposed drift of 5% for the subassembly investigated when no gap was provided between slab and the column. It was also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 10% for a maximum imposed drift of 5% for the subassembly investigated when a gap was provided between the slab and the column.
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Strozzi, A., and G. Monegato. "On the incompatibility between the equivalent shear force concept and the integral formulation of contact problems between Kirchhoff plates and irregular linear supports." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 7 (July 1, 2008): 1149–63. http://dx.doi.org/10.1243/09544062jmes801.
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It is shown that, when employing the integral formulation to describe contact problems between Kirchhoff plates and irregular linear supports, the equivalent shear force concept may be incompatible with the integral approach. In such circumstances the equivalent shear force concept has to be abandoned in favour of an equivalent twisting moment approach. A classical example of an infinite plate resting on a linear central segment is revisited in the light of the equivalent twisting moment concept, where all the computations are carried out in exact form. An additional example is developed to show that the usefulness of an integral approach based upon the equivalent twisting moment concept remains valid even when the equivalent twisting moment is applied at a plate border along which the twisting moment must be null, as it occurs in a partially clamped border. The reaction singularity at the endpoints of a linear support is examined with the Williams asymptotic method. Finally, a physical interpretation is proposed for the adoption of a distributed twisting moment among the contact reactions.
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Złoto, Tadeusz, and Konrad Kowalski. "Load of the slipper-swash plate kinematic pair of an axial piston pump." MATEC Web of Conferences 157 (2018): 08013. http://dx.doi.org/10.1051/matecconf/201815708013.
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The paper presents problems related to the twisting moment of the slipper. The load of the slipper and the piston has been presented and the complex formula of twisting moment of the slipper has been established. Achieved results has been presented graphically. The conducted research has indicated that the value of the twisting moment relays on both the exploitation and geometrical parameters.
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SERBEST, KASIM, MILAIM BERISHA, and MURAT CILLI. "DYNAMIC ANALYSIS OF THREE DIFFERENT HIGH BAR DISMOUNTS IN THE SIMMECHANICS ENVIRONMENT." Journal of Mechanics in Medicine and Biology 18, no. 03 (May 2018): 1850030. http://dx.doi.org/10.1142/s0219519418500306.
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This study compares certain kinematic and kinetic parameters in giant circles performed before twisting, double stretched and double tucked dismounts using the dynamic model in the SimMechanics environment. The joint moments calculated using the designed model were investigated for the three different dismounts. The study included a 13-year-old voluntary national gymnast with seven years of training history. Markers were placed on the wrist, elbow, shoulder, hip, knee and ankle joints of the gymnast. The gymnast was asked to perform twisting, double stretched and double tucked dismounts. MATLAB and SimMechanics were used to calculate joint moments. The moves were simulated and the joint moments during the moves were calculated using the SimMechanics toolbox. The study observed that the highest joint moment was in the wrist joint in all three dismounts, in line with the findings of previous studies. However, unlike other studies, higher joint moments were calculated in the accelerated giant circle performed together with thrusts, compared with the regular giant circle. While there were similar maximum moment values in twisting dismounts and double tucked dismounts, an almost three times higher moment was observed in double stretched dismounts. In terms of joint moments, stretched dismount is obviously the most difficult move, which is consistent with the difficulty levels. A recorded performance of the mechanical model created in the SimMechanics environment was investigated in terms of the twist angle and moments generated on the bar, and found to be sufficient and useful. However, there are certain restrictions regarding the methods employed in this study. We concluded that the mechanical model will allow for the performance of kinematic and kinetic analyses of different gymnasts and types of moves thanks to its flexible structure.
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Li, Jun Lin, Xue Xia Zhang, and Wei Yang Yang. "An Analysis of Fracture Problems of Orthotropic Composite Plate under Bending and Twisting." Key Engineering Materials 306-308 (March 2006): 805–10. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.805.
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An analysis of fracture problems near crack tip for linear elastic orthotropic composite plate under bending and twisting is carried out. By solving the boundary value problem of partial differential equations and applying the method of undetermined coefficients, the two group expressions for bending moment, twisting moment and displacement near crack tip are derived. The formulae have certain practical and referential value in related fracture analysis.
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Zhang, En Wei, Yun Bo Yang, Wei Song, Xiao Wei Wei, Zhi Bin Qiu, Jiang Jun Ruan, and Dao Chun Huang. "Study on Bending and Twisting Mechanical Properties of High Voltage Porcelain Post Insulator." Applied Mechanics and Materials 521 (February 2014): 334–38. http://dx.doi.org/10.4028/www.scientific.net/amm.521.334.
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To study the mechanical properties of porcelain post insulators, the finite element model was established by ANSYS to calculate stress and strain distribution under bending or torsion moments. Mechanical tests based on resistance strain measurement technology were carried out on the actual porcelain post insulators to measure their strain distribution. The results show that sheds will cause strain concentration at the roots of porcelain column whether the post insulator is bearing bending or torsion load. The stress and strain of shed roots gradually increase from top to bottom along the post insulator when bearing bending moment, while they are relatively uniform under torsion moment. It should be taken full account of the stress concentration caused by sheds during the selection or maintenance of porcelain post insulators.
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Chen, Xu Qin, Gui Lan Jiang, and Guang Zhen Cheng. "Material Mechanical Performance about Worm Bending and Twisting Deformation for Civil Engineering." Advanced Materials Research 568 (September 2012): 187–90. http://dx.doi.org/10.4028/www.scientific.net/amr.568.187.
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On the condition of line elastic and small deformation, more than 80% failure of the drive shaft is due to fatigue damage. It relates to the alternating stress of the drive shaft under the combination effect of bending and twisting. When drive shaft is under the combination effect of bending and twisting for civil engineering, torsion shear stress is perpendicular to bending normal stress. They can’t be simply stacked. Combining with the belt conveyor tension device of the worm transmission, first, simplify the external force; do stress analysis in horizontal plane and vertical plane respectively. Then make corresponding bending moment figure and separately calculate the internal force, stress of each basic deformation and make comprehensive bending moment figure and torque figure. Then use the application of superposition principle, the fourth strength theory to calculate worm transmission’s strength. The method makes senses to other transmission mechanism shaft bending and twisting combination strength analysis as a reference.
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Sinha, Hemant K., S. Muralidharan, and Keith Yates. "Ground and excited state dipole moments of planar vs. twisted p-N,N-(dimethylamino)benzonitrile systems: maximum charge transfer for minimum overlap." Canadian Journal of Chemistry 70, no. 7 (July 1, 1992): 1932–38. http://dx.doi.org/10.1139/v92-242.
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Electric field induced change in the absorption spectrum (electrochromism) has been employed to obtain the ground and excited state dipole moments of planar and sterically hindered (twisted) p-N,N-(dimethylamino)benzonitriles in dioxane solution. These studies support the twisted intramolecular charge transfer (TICT) hypothesis and provide additional insight to the TICT concept. The charge transfer nature of the excited state has been found to directly depend on the torsional angle of the N,N-dimethylamino group with respect to the benzonitrile moiety. It is suggested that solvent coupling is essential to initiate twisting by affecting the intramolecular degrees of freedom and the existence of the highly dipolar excited state is a result of such twisting of the donor–acceptor bond. Theoretical calculations have been performed to explain the observed changes in dipole moment values.
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Petazzoni, Massimo, Fabio Carli, Micheal Kowaleski, and Roberto Tamburro. "Comparison of Rotation Force to Maintain Acetabular Ventroversion after Double Pelvic Osteotomy and 2.5 Pelvic Osteotomy in a Canine Cadaveric Model." Veterinary and Comparative Orthopaedics and Traumatology 31, no. 01 (2018): 062–66. http://dx.doi.org/10.3415/vcot-16-09-0135.
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Objective The aim of this article was to compare the force required to maintain the acetabular ventroversion after double pelvic osteotomy (DPO) and modified triple pelvic osteotomy (2.5PO). Methods Unilateral DPO (group A) and unilateral modified DPO (group B = 2.5PO) were performed on cadaveric canine pelves (n = 10/group). The twisting moment required to maintain fragment position for DPO and 2.5DPO was compared. Results Mean twisting moment for the DPO group [5.92 N/m ± 2.59 (range, 2.61–12.17 N/m)] and the 2.5PO group [2.11 N/m ± 0.93 (range, 0.63 -3.85 N/m)] was significantly different (p < 0.01). Conclusion Dorsal cortex osteotomy of the ischium decreases the acetabular segment rotation force. Decreased force may facilitate acetabular rotation during DPO procedure.
Dissertations / Theses on the topic "Twisting moment"
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Jurnečka, Ladislav. "Torzní tuhost rámu Formule Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231527.
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Diploma thesis deals with detection of torsional stiffness with using photogrammetric equipment TRITOP device and subsequent comparison with created computational model in FEM software. Measurement and calculations were accomplished according to tutorials, which are the most effective and giving the most accurate results. Next the optional method of measurement of torsional stiffness in practice is formed for future formula series called Dragon. The reasons of different results and suggestion of optimalization are sum up in the end of the thesis.
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Lodi, Sarosh Hashmat. "Reinforced concrete slab elements under bending and twisting moments." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/1192.
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Li, Hong-Chi, and 李弘基. "On an Elastic Rod inside a Tube under End Twisting Moment." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/01600304560041128854.
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碩士臺灣大學
機械工程學研究所
98
In this paper we study the deformation of a thin elastic rod constrained inside a cylindrical tube and under the action of an end twisting moment. The ends of the rod are clamped in the lateral direction at the centers of the tube. Unlike the previous works of others, in which only the fully-developed line-contact spiral was considered, we present a complete analysis on the deformation when the dimensionless twisting moment Mx is increases from zero. It is found that the straight rod buckles into a spiral shape and touches the inner wall of the tube at the midpoint when Mx reaches 8.987. As Mx increases to 11.472 the contact point in the middle splits into two, leaving the midpoint floating in the air. As Mx increases to 13.022, the midpoint returns to touch the tube wall and the two-point-contact deformation evolves to a three-point-contact deformation. Starting from Mx=13.098, the point contact in the middle evolves to a line contact, and the deformation becomes a point-line-point contact configuration and remains so thereafter. In the case when the line-contact pattern is fully developed, it is possible to predict the spiral shape analytically. The numerical results are found to agree very well with those predicted analytically. Finally, an experimental set-up is constructed to observe the deformation evolution of the constrained rod under end twist.
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Ramos, James Silva. "Avaliação teórica do comportamento à torção de lajes de betão armado." Master's thesis, 2013. http://hdl.handle.net/10316/38476.
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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraNeste trabalho é feita uma avaliação teórica do comportamento à torção de lajes de Betão Armado (BA). Em virtude dos resultados obtidos em ensaios experimentais, sabe-se que a curva que define a resistência à torção de lajes de BA é constituída por três fases distintas: A fase linear elástica, não fissurada; a fase não linear, de desenvolvimento de fissuras até se atingir a cedência e por último, a fase de plastificação das armaduras até se atingir a rotura no ponto de carga máxima. Um aspecto relevante para a análise da curva momento torsor-rotação unitária T-θ, é a diminuição acentuada da rigidez ao se passar da fase inicial para a segunda fase. Assim, a avaliação consiste na análise de resultados experimentais, de lajes quadradas ensaiadas à torção pura, e na análise de resultados obtidos com modelos numéricos, recorrendo a dois programas computacionais distintos. Com o objectivo de caracterizar o comportamento genérico de lajes de BA sujeitas à torção, são feitos testes paramétricos, a nível numérico, relativos à geometria, às características do betão e às características do aço, constituintes das lajes. Os resultados obtidos são confrontados com os experimentais a fim de se chegar a relações que permitam a caracterização de cada uma das fases da curva do comportamento. Por um lado, são propostos parâmetros adimensionais, designados de momentos torsores reduzidos, que reúnem as relações paramétricas e facilitam a obtenção dos momentos torsores nos pontos característicos das curvas. Por outro lado, são propostas equações simples para a obtenção da rotação unitária nos mesmos pontos. Assim se define a pretendida curva genérica do comportamento. É verificada a aplicabilidade e a fiabilidade dos resultados ao serem confrontados com os exemplos experimentais disponíveis. Os resultados obtidos são analisados e discutidos. Apresentam-se também as principais conclusões a que se chegaram bem como as sugestões para a continuação do desenvolvimento deste tema no futuro.
This work comprises a theoretical evaluation of the torsion behaviour of Reinforced Concrete (RC) Slabs. Experimental tests have shown that the curve that defines the resistance to torsion of RC slabs is composed by three different stages: the elastic non-cracked linear stage; the linear cracked stage, characterized by the development of cracks until yielding of steel is reached and, finally, the stage of the steel plastification until rupture is reached at the maximum load value. A relevant aspect concerning the T-θ rotation-torque curve is the clear reduction of stiffness at the transition point from the initial phase to the second stage. Thus, the evaluation consists on an analysis of the experimental results regarding square slabs tested under pure torsion, and of a further analysis of the results obtained with numeric models by using two distinct computing programs. Aiming at characterizing the generic behaviour of concrete slabs subject to torsion, parametric tests are carried out at the numeric level regarding the geometry and characteristics of the type of concrete and steel that the slabs are made of. The results obtained are compared to the experimental results in order to find the relations that best reflect each of the stages of the behaviour curve. Non-dimensional parameters, herein termed reduced torque, are proposed to gather the parametric relationships that would lead to the generic wanted curve. The rotation value can be obtained from simple equations also proposed. The applicability and reliability of the reduced moment are checked when these are applied to the available experimental examples. The results are analyzed and discussed. The main conclusions as well as the suggestions to continue the development of this topic in the future are also presented.
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Yao, Kuang-Ta, and 姚光大. "The effect of clockwise and counterclockwise twisting moments on abutment screw loosening." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31336440845312698220.
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碩士國立陽明大學
臨床牙醫學研究所
99
Objectives： Abutment screw loosening is one of the most common complications of dental implants. When occlusal loading is applied, bending and twisting moments are counteracted by the implant-abutment connection held with the abutment screw. Restorations in different quarters of the oral cavity might bear clockwise or counterclockwise twisting moments that result from a regular chewing pattern. Because the most convenient way to loosen the screw is reversing, the directions of twisting moment might have an influence on screw loosening. The aim of this study was to investigate the effect of different directional twisting moments on abutment screws. Material and methods： Twenty 3i implants were divided into four groups of C, R, L, and O. Each assembly consisted of an implant, abutment, abutment screw, and superstructure. For group C, a cyclic load of 10 to 100 N for 106 cycles was applied centrally and perpendicular to the long axis of the implant, whereas for groups R and L, the same load conditions were applied eccentrically in clockwise and counterclockwise directions, respectively. Group O was left unloaded. The difference between the initial torque and post-loading reverse torque was defined as the total torque loss. The data were analyzed by Kruskal-Wallis test. The surfaces of the abutment hexagon corners were examined with SEM after loading. Results： No abutment screw loosening was found after loading. Total torque loss of groups C, R, L, and O were 10.50±0.58, 9.56±1.01, 9.98±1.81, and 9.58±0.94 Ncm, respectively. There were no statistical differences among the four groups. SEM observations showed marked burnishing at the hexagonal corners on the compression sides of the R and L groups. Conclusions： Within the limitations of this study, there was little effect of twisting moment direction on the total torque loss of an internal hexagon connection implant system. This could be attributed to the anti-twisting mechanism of the internal hexagon connection.
Books on the topic "Twisting moment"
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Tupling, Susan Janet. Segmental angular momentum analysis of somersaulting and twisting movements. 1989.
Find full textBook chapters on the topic "Twisting moment"
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"FIGURE 14.3 Evaluation of twisting moment." In Finite Element Analysis, 199–205. CRC Press, 2003. http://dx.doi.org/10.1201/9780203009512-38.
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Woloch, Isser. "The Roosevelt Era: From the New Deal to D-Day." In The Postwar Moment, 86–136. Yale University Press, 2019. http://dx.doi.org/10.12987/yale/9780300124354.003.0003.
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This chapter looks at the progressive forces in the U.S. In the U.S., Franklin Roosevelt's presidency became the prime force for progressive gains. In the New Deal's ascendant phase from 1932 to 1936, the agricultural and industrial recovery strategies of the “Hundred Days” came first and foundered. Later, Roosevelt's administration enacted social security, inventive new programs for work relief, and the Wagner labor relations act that changed the rules of the game for trade unions. Once the European war began in 1939, the U.S. gradually became “the arsenal of democracy.” However, only on a fraught and twisting path did Roosevelt finally lead America into the crucible of World War II. Meanwhile, a new social movement reinforced the progressive thrust of Roosevelt's presidency—the rise of new trade unions in the mass production industries impelled by the CIO (Congress of Industrial Organizations), a new labor federation.
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Kakavas, P. A., A. P. Vassilopoulos, and J. Boviatsis. "Prediction of the twisting moment and the axial force in a circular rubber cylinder for combined extension and torsion based on the logarithmic strain approach." In Constitutive Models for Rubber IV, 421–24. Routledge, 2017. http://dx.doi.org/10.1201/9781315140216-69.
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Eimeleus, K. B. E. E. "Skis as a Brake." In Skis in the Art of War, translated by William D. Frank and E. John B. Allen, 70–72. Cornell University Press, 2019. http://dx.doi.org/10.7591/cornell/9781501747403.003.0020.
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This chapter discusses using skis as a brake. For a skier-sportsman, braking with skis is a more suitable solution, but it requires better command over one's equipment than braking with poles. A skier can brake with both skis, or just one (in two distinct styles). When braking with two skis, the tips draw together while the tails tend to split apart. This method works well on hard snow; in soft snow, one must employ it gradually, otherwise a large pile of snow accumulates in front of the skis, movement stops abruptly, and a skier tumbles forward from their momentum. A variation of this is braking with one ski, which offers two possibilities: both of them are twisting motions.
Conference papers on the topic "Twisting moment"
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Lachenal, Xavier, Stephen Daynes, and Paul Weaver. "Concept for a Bistable Composite Twisting Structure." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5070.
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A novel type of morphing twisting structure capable of large deformations is investigated. The structure consists of two flanges subject to a uniform distributed bending moment along their length and joined to introduce two stable twisted configurations. These equilibria are positioned symmetrically with regards to the vertical axis of the device and the structure can be twisted between these configurations by a snap-through action. By tailoring the design parameters of the structure, different twist angles and snap-through moments can be achieved. An analytical model and finite element model (FEM) are presented. A prototype made of carbon-fibre reinforced plastic (CFRP) was manufactured and tested. Agreement in terms of angle of twist, axial force and stiffness is found. Moreover, comparison between the two models confirms their validity in terms of snap-through moment, torsional stiffness and strain energy levels. The influence of the lay-up employed and design parameter is also investigated. Potential applications include deployable and morphing structures.
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Okayama, Koichi, and Toshimichi Fukuoka. "Three-Dimensional Finite Element Analysis of Rigid Flanged Shaft Coupling Subjected to Twisting Moment." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97482.
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A reamer bolt is commonly used when clamping a rigid shaft coupling subjected to large shear force. Although some joint design procedures assume that the applied shear force transmits only through the reamer surface, it is also supported by the friction force on the contact surfaces. Accordingly, to design the coupling clamped by reamer bolts, it is important to evaluate the ratio of the shear forces supported by the reamer surface and the friction force, which is defined as shear force transfer ratio (SFTR) here. In this study, distributions of SFTR and the bending stresses along the reamer surface are analyzed by three-dimensional FEM, focusing on the effects of the fit between the reamer bolt and bolt hole, the scatter of initial bolt stress and the misalignment of the connecting shafts. Numerical results quantitatively clarify how the amounts of the SFTR and the bending stresses as the friction coefficients, the fit and the magnitude of misalignment are changed. As for an offset misalignment, it is found that its effect on the bending moment generated in the shaft body is negligibly small, if the offset between two shafts in radial direction is less than 10mm which is 1% of the total shaft length.
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Mohammad, Fouad, and Emmanuel Ayorinde. "Simplified Procedure to Estimate the Wind Turbine Blade Aerodynamic Loadings Without Using CFD." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65427.
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The aerodynamic loadings that act on the blade of a horizontal axis wind turbine change as a function of time due to the instantaneous change of the wind speed, the wind direction and the blade position. The new contribution in this study is the introduction of a simplified non CFD based procedure for the calculation of all the aerodynamic loadings acting on a wind turbine blade. The premise of the current simplified model is that (a) the forces can be modeled by a set of point loads rather than distributed pressures, and (b) the magnitudes of these point loads can be estimated using the below load formulas, (c) an interpolation scheme needed to have all computed forces and moments as a function of the blade lengthwise x. Considering a 14m blade length and utilizing a time dependent set of parameters such as angle of attack, material and air density, wind and blade speed, flow angle, yaw, pitch angles, the centrifugal forces (along x-direction of the blade length), the cross-sectional forces (Fy and Fz) and the twisting moment of the blade (about the x-direction) were calculated for each of all the given time steps. After that the authors explain how to interpolate the calculated loadings (forces and twisting moment) and the right formulas to compute the aerodynamic load vector (the right side of the dynamic equations of motion).
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Hase, Aniket Anil, and Jen-Yuan (James) Chang. "Multiple Point Loading on Thin Cantilever Rectangular Plate Subjected to Pure Bending." In ASME 2021 30th Conference on Information Storage and Processing Systems. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/isps2021-65262.
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Abstract In the applications of pure bending of thin cantilever plates, unlike a beam, twisting arises with the bending unless it is accomplished to pure bending. This paper emphases the theoretical study of the integration of multiple point loadings (vertical and Inclined) over the thin plate to eliminate the twisting and predict the definite bending for the linearly elastic material. The cantilever plate is further studied through numerical simulations using finite element analysis (FEA) in ANSYS. This FEA helps to finalize the type of modelling approach that predicts large deflection’s behaviour agreeing closely with theoretical solutions. Also, in the experimental procedure, various artificial intelligence (A.I.) techniques can reduce complexity; minimize the dependence on humans, and improve design efficiency. The process presented in this paper is inspired by Euler’s classical beam theory (moment-curvature relationship) and ANN, which approximates the problem and compensates the errors.
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Gnanavel, B. K., G. Raja, and D. Chandramohan. "Effect of Interfacial Contact Forces and Lay Ratio in Cardiac Lead Outer Insulation due to Internal Cable Motion." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23091.
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Abstract Wearing cardiac lead implanted may result in various failures, including in-appropriate or missing treatments. Contacts are used on the lateral and radial link in the multi-layered (1 + 6 + 12) pacemaker lead cable. The effect of the coupling mode, however, is not the same as it does when the lateral and radial contact combine. On the transverse wire the forces and moments developed along the regular, bi-natural, and axial directions on a helical wire of the multi-faceted pacemaker cable. The equilibrium equations derived from Love’s thin rod theory (1944) shall provide geometric nomenclatures of the cabling generated by axial stress and rotational pressures from the multi-layered pacemaker lead. A steepness matrix is derived for multi-layered pacemakers leading cable elements, leading to strand strength, a twisting moment, axial strand strain and rotational strain.
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Jackson, Peter. "An Improved Upwind Sail Model For VPP's." In SNAME 15th Chesapeake Sailing Yacht Symposium. SNAME, 2001. http://dx.doi.org/10.5957/csys-2001-002.
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In velocity prediction programs for yachts the problem of modelling sail forces is greatly complicated by the fact that the sail shapes are not fixed. For a given sail plan, alterations in sail trim produce a wide range of combinations of lift, drag and heeling moment. While the original solution to this problem using the well-known parameters flat and reef has been very successful, it has some obvious defects. In particular, it does not correctly model the practice of twisting a sail to reduce heeling moment. This paper therefore sets out an improved model which satisfies the essential requirements for upwind sails; namely that the model is based upon fundamental aerodynamic principles, allows all the unknowns to be determined from tests (full scale or wind tunnel) and permits the best sail trim to be selected for optimization of performance. The essential new step is to introduce a new trim parameter twist which correctly accounts for the practice of allowing the head of a sail to twist off in order to reduce heeling moment.
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Brockmeyer, Landon, Aleksandr Obabko, Elia Merzari, and Yassin Hassan. "Analysis of Pressure Field on Wire-Wrapped Pin Bundle Surface for Concerns of FSI." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83521.
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Wire wrapped fuel pins, typical of sodium fast reactor designs, introduce a strong secondary rotational flow and enhanced mixing compared to bare pins found in many other nuclear reactor designs. The transverse flow is created by deflection off of the helical wires, exerting a force onto the wires. The resulting pressure field can be more intricate than found for bare fuel pins. There is an increased concern for fluid structure interactions such as twisting, bending, and vibration due to the fluid deflection and increased transverse flow. The present study uses LES to simulate the fluid flow in a wire-wrapped fuel pin bundle. The simulation is performed using Nek5000, a spectral element LES/DNS code. The time-dependent, fluctuating pressure field at the surface of select fuel pins are specifically captured for analysis. Statistical analysis is performed on the pressure data to find areas of persistent force or bending moment, which over large periods of time may result in deformation of the pins. Further, the pressure data is analyzed in search of areas with large fluctuations in pressure, which may result in flow induced vibrations. Frequency spectra of the force fluctuations are analyzed.
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Aziz, Saad, John Gale, Arya Ebrahimpour, and Marco P. Schoen. "Passive Control of a Wind Turbine Blade Using Composite Material." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63899.
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The weight and the cost of a wind turbine are two important factors that make wind energy competitive with other energy sources. The weight of the rotor is typically 40–80% of the total weight of the system. Thus, lowering cost by reducing the weight of the blade is an important consideration. Another significant factor is the operational life of the machine. At present, a wind turbine’s life span is about 108 cycles or 20 years of continuous service. Innovative design solutions are needed in order to meet the criteria of improved stiffness, fatigue life, reliability, and efficiency. The directional property of an anisotropic composite material can be used to passively control wind turbine blade geometry in fluctuating wind speeds. Anisotropic materials show various levels of elastic coupling, based upon the ply angle in the layers. Structural behavior that exhibits both bending and twisting due to a pure bending load is known as twist-bend coupling. This type of behavior can be used for load reductions, particularly fatigue loads. The idea is to allow the blade to unload (reducing the speed) by allowing the wind induced bending moment to twist the blade. Increments in bending moment produce an increment in the twist that lowers the aerodynamically produced load. Higher blade stiffness can be achieved by full or partial replacement of glass fiber with carbon fiber. Carbon fibers are not used extensively on commercial wind turbine blades as they are more costly than glass fiber. The main objectives of this work are: (1) design a baseline model (made from glass fibers) of the wind turbine blade in accordance with published airfoil data; (2) conduct a finite element analysis of the blade and determine stresses, and strain within the blade; (3) develop a hybrid blade design by replacing the glass fibers with carbon fibers in the spar cap; and (4) validate the feasibility of implementing bend-twist coupling in the wind turbine blade by studying stresses, and strain behavior. By giving different orientation in the carbon fiber and changing the fiber layer, different designs are analyzed with regard to the above listed criteria.
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Ramos, Roberto, Clo´vis de Arruda Martins, Celso Pupo Pesce, and Francisco E. Roveri. "A Case Study on the Axial-Torsional Behavior of Flexible Risers." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57514.
Full textAbstract:
Flexible risers are complex structures composed of several concentric polymeric and steel armor layers which withstand static and dynamic loads applied by the floating production vessel and by the ocean environment. Determining the axial and torsional stiffness values of such structures is an important task for the global structural analysis, since it provides a probable value that can be used in this analysis to predict the load distribution along the line and permitting, thus, to estimate the expected life of the structure. Although such stiffness values may be provided by the manufacturer, it is quite desirable that they can be estimated by analytical models instead. However, any analytical model proposed for such a task must be checked with well-conducted experimental results in order to be considered as an acceptable analysis tool. The aim of this work is to present the main results involving axial-torsional tests in a 2.5" flexible riser, carried out at the Technological Research Institute of Sa˜o Paulo (IPT). Besides presenting full data concerning the internal structure of the riser, this paper describes the experimental procedures used to perform the tests and the main obtained results (e.g., Force × Displacement and Twisting moment × Displacement curves). Tests involving internal pressure were also performed and the obtained results are also presented in this work. Comparisons between analytically calculated values of the axial and torsional stiffnesses with those obtained experimentally are made and discussed. A brief discussion about the validity of some hypotheses which are usually assumed by analytical models found in the technical literature is made at the end of the work.
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Reddy, Sohail R., George S. Dulikravich, and Helmut Sobieczky. "Bladelets-Winglets on Blades of Wind Turbines: A Multiobjective Design Optimization Study." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70220.
Full textAbstract:
The work presented in this paper used rigorous 3D flow-field analysis combined with multi-objective constrained shape design optimization for the design of bladelet (winglet) configurations for a three-blade propeller type wind turbine. The fluid flow analysis in this work was performed using 3D, steady, incompressible, turbulent flow Reynolds-averaged Navier-Stokes equations in the rotating frame of reference for each combination of a given wind turbine blade and a varying bladelet geometry. The free stream uniform wind speed in all cases was assumed to be 9 m s−1 and rotational speed was 12 rpm. These were off-design conditions for this rotor. The three simultaneous design optimization objectives were: a) maximize the coefficient of power, b) minimize the coefficient of thrust, and c) minimize twisting moment around the blade axis. The bladelet geometry was fully defined by using a small number of parameters. The optimization was carried out by creating a multi-dimensional response surface for each of the simultaneous objectives. The response surfaces were based on radial basis functions, where the support points were designs analyzed using the high fidelity CFD analysis of the full blade + bladelet geometry. The response surfaces were then coupled to a multi-objective optimization algorithm. The predicted values of the objective functions for the optimum designs were then again validated using the high fidelity computational fluid dynamics analysis code. Results for a Pareto optimized bladelet on a given blade indicate that more than 4% increase in the coefficient of power at minimal thrust force penalty is possible compared to the same wind turbine rotor blade without a bladelet.