共查询到20条相似文献,搜索用时 48 毫秒
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运用体积微可压缩法的三维刚粘塑性有限元方法.对轴对称体的扭压成形变形规律进行了模拟分析.结果表明:与一般镦粗成形相比,扭压成形具有可促使变形均匀、增加变形量等优点. 相似文献
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本文采用刚塑性有限元理论,开发了一个二维数值模拟程序系统,对盒形件拉延成形中的法兰变形区进行了较全面的数值模拟,研究了冲压成过程中法兰变形区的金属流动规律。 相似文献
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Yeong-Bin Yang Jung-Huai Chou Liang-Jenq Leu 《International journal for numerical methods in engineering》1992,33(8):1597-1610
The purpose of the paper is to demonstrate how the concept of rigid body motions can be employed to derive the external stiffness matrix for an initially stressed finite element. Such a matrix is as important as the elastic and geometric stiffness matrices. It can be used not only in an eigenvalue analysis for testing the zero energy modes of a finite element under initial loadings, but for calculating the element forces in a step-by-step non-linear analysis. The two-dimensional beam element presented in this paper serves as a vehicle to demonstrate the concept involved. The principle of virtual work in its updated Lagrangian form has been adopted as the method of formulation. Several examples are provided to illustrate the adequacy of the present approach. 相似文献
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Meng Tao Dong Cuige Peng Chaoqun Wang Richu Feng Yan 《Journal of Materials Science》2022,57(1):717-730
Journal of Materials Science - The characterization of hot deformation behavior and determination of hot processing parameters of Mo-50Cu composites were studied by the isothermal compression tests... 相似文献
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Ehud Ben-Sabar Bruce Caswell 《International journal for numerical methods in engineering》1979,14(4):545-565
A finite element simulation of the equations of momentum and energy transport in fluids has been implemented with triangular elements. An attempt is made to single out the reasons for numerical instabilities reported by other investigators for convection–diffusion transport operations in fluid mechanics when the ratio of the convective to the diffusive terms, measured by the Reynolds and Peclét numbers, is of the order of a hundred. To this end, the equations are solved for several problems to permit a direct comparison with results of other formulations. It is shown that the appearance of instability can be delayed by a proper choice of boundary conditions, and its intensity can be reduced through the use of triangular finite elements. Results agree very well with theoretical solutions for particular test problems including flows with large convection effects, large dissipation effects and fluids with temperature dependent properties. 相似文献
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Harit K. Raval Anish H. Gandhi Mukesh M. Makwana Harshit K. Dave Yogesh K. Srivastav 《International Journal of Material Forming》2013,6(1):115-124
Hot forming is an important forming method for production of small and medium sized single-piece pressure vessel dish ends. Thinning of the blank material with increased degree of forming is quite obvious. Present work shows finite element (FE) analysis of hot forming of single-piece hemispherical dish end (SPHDE) for predicting maximum thinning of blank during forming. Thinning analysis is performed for SPHDE of two different ferrous material grades SA-387 Gr22 and SA-516 as per ASME, Section II, Part A (2004). Percentage thinning results of FE analysis are verified with the practical material thinning data. Based on the thinning analysis, empirical relation for calculation of percentage thinning as a function of different dish ends′ geometry parameters is proposed. Empirically predicted percentage thinning is observed to be in good agreement with practical and FE simulation results. Thinning results obtained based on proposed FE simulation and empirical model can be helpful to design engineer in selecting thickness of developed blank considering thinning allowance for hot forming of SPHDE. Thinning analysis data can be used for optimizing the dish end geometrical parameters for minimum thinning during forming. 相似文献
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依据有限元方法的基本物理思想,在某些不需要计算辐射声场的准确声学参数和波束特性的工程应用方面,对流体模型进行充分简化,提出了简化模型处理的有效方法,利用该方法对超声换能器进行模拟分析,并进行了样品的制作和测试,实测结果与模型简化分析处理的结果基本一致。可以证明,用该方法进行换能器的优化设计是可行和高效的。 相似文献
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Miguel A. Cavaliere Marcela B. Goldschmit Eduardo N. Dvorkin 《International journal for numerical methods in engineering》2001,52(12):1411-1430
In this paper we discuss our finite element procedure for simulating the hot rolling of flat steel products. We couple an Eulerian rigid‐viscoplastic model of the steel plates deformation to a Lagrangian elastic model of the rolls deformation. This latter model incorporates the bending deformation of the work rolls supported by the back‐up rolls and the flattening of the contact areas (Hertz problem) via an enhanced beam model. The finite element model is validated comparing its predictions with actual industrial measurements and then it is used to analyse different rolling set‐ups. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Darren L. Rice Edward C. Ting 《International journal for numerical methods in engineering》1993,36(22):3859-3881
An algorithm which combines the techniques of numerical analysis and numerical simulation in the study of transient dynamic structural response is proposed. This is achieved by incorporating the ability to create new surfaces and separate fragments according to a defined failure criterion into a finite element procedure which uses explicit time integration. Thus, the algorithm not only provides accurate prediction of the structural failure and fragmentation pattern, but also evaluates accurate stress, velocity, acceleration and displacement values of each fragmented component. To develop a viable fragmental algorithm, other than the expected modification in storage and node bookkeeping, we found it necessary to introduce an efficient algorithm to handle extremely large displacements resulting from the fracture. In that regard, an updated corotational approach is introduced. 相似文献
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The present article deals with micromechanical composite modeling. Both analytical and computational micromechanics approaches are described as well as micromechanical modeling of damage. Based on micromechanics of failure theory, a user subroutine including a progressive damage algorithm is programmed for finite element analysis. Three theory-experiment correlations of tubes under a three-point bending test have been carried out using the bi-phase material model developed along with this project. These studies include three-ply schedules. 相似文献
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J. P. Hennart R. England J. G. Martin L. Melendez L. 《International journal for numerical methods in engineering》1979,14(10):1449-1460
A numerical model is proposed to simulate the space-time behaviour of a low-density plasma in a linear multipole. Semi-discrete Galerkin techniques are used in conjunction with triangular finite elements. For both space and time discretizations, special techniques are developed to numerically separate the effect of rapid diffusion along the field lines from the slow perpendicular diffusion. Numerical results are exhibited to show how these techniques succeed in eliminating the problems caused by the strong anisotropy of the diffusion coefficient in the strongly curved and very inhomogeneous multipole configuration. 相似文献
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A new approach of dealing with mesh dependence in finite element modelling of fracture processes is introduced. In particular, in brittle fracture modelling, the stress concentration is mesh dependent as the results do not stabilise when refining the mesh. This paper presents an approach based on the explicit incorporation of mesh dependence into the computations. The dependence of the relevant stress is quantified on the finite elements at the crack tip upon the element size; when the dependence approaches a power law with the required accuracy, the mesh is called scalable. If the mesh is scalable and the exponent and pre-factor are known, then the results of the computations can be scaled to the size relevant to the scale of the physical microstructure of the material; the latter while not being modelled directly ultimately controls the fracture propagation. To illustrate this new approach, four 2D examples of a single straight crack loaded under tensile and shear tractions applied either to the external boundary or to the crack faces are considered. It is shown that combining the stresses at the crack tip computed using a set of similar meshes of different densities with the crack tip asymptotic allows accurate recovery of the stress intensity factors. 相似文献