可扩展冲击-接触并行计算及其在汽车碰撞模拟中的应用
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
大型复杂结构系统的冲击接触,例如汽车碰撞,涉及大变形的几何非线性、弹塑性本构的材料非线性、多接触面的边界条件非线性,而且是高自由度系统的瞬态动力响应问题。此类问题的数值模拟通常要对数十万自由度系统进行数十万时间步的响应计算,对于计算机的存储量和计算时间都提出了很高的要求,在不具备超级计算机的条件下,通常很难获得满足工程需要的计算结果。为此本文研究了此类问题在微机机群环境下的可扩展并行算法,并改进了区域自动划分算法,并将这些算法应用到汽车碰撞的数值模拟,取得了比较满意的结果。本文主要内容包括如下几个部分:
    首先,为了有效地进行大型复杂结构系统的冲击接触数值模拟,需要保证包含诸多复杂因素的计算模型充分协调。为此,文中从推导变分方程开始,给出了包括接触边界条件、壳单元内力计算在内的全部列式,并列出了识别接触界面的搜索算法,接触力计算以及动力响应计算的时间积分算法的有关公式等等。本文的计算格式不仅使上述各部分之间协调相容,并且通过不同算例表明,它具有较高的计算效率。
    本文分别设计了内力计算、接触搜索和接触力的并行算法。内力计算部分和接触计算部分所基于的区域分裂都在单元级上完成,避免了以前冲击-接触并行计算时两部分之间的不相容性的问题。提出了一种修正的greedy算法以完成区域自动划分的任务,相对于传统的greedy算法,新算法使得分割子域具有更好的长宽比,且适用于不规则几何形状的有限元网格的区域划分。
    最后,在微机机群环境下采用上述模型和提出的算法实现了汽车碰撞模拟的大规模并行计算。计算中采用了双重动态区域划分技术,但内力计算和接触计算区域划分均在单元级上完成,从而保持了计算模型的一致性。实际车架和整车碰撞模拟的结果通过与试验结果的比较证明是合理的,关键结果曲线趋势吻合,数值接近。微机机群并行计算比单台微机计算能显著减少计算时间,并具有良好的可扩展性。在八结点机群环境下,并行加速比可达到5.5,对于150000自由度的整车碰撞问题,计算160000个时间步,计算时间仅为7.26小时。从而说明在机群环境下,通过并行计算,可以胜任汽车碰撞工程问题的数值模拟。
Contact-impact of large-scale complex structural system, such as car crash, is involved with geometric nonlinearity caused by large deformation, material nonlinearity due to elastoplastic constitutive relation, and boundary nonlinearity related to multiple contact surfaces; furthermore it is transient response of a system with large number of DOF. For the numerical simulation of such problem, in general, it is required to carry out the response computation of several hundred thousands time steps for a system with several hundred thousands DOF, which raises very high demand for the memory of computer and the computing speed. It was very difficult to obtain the satisfactory results required by the engineering practice without supercomputers. In order to improve such situation, it is dealt with the scalable parallel algorithm for the simulation of such problem on a PC cluster in this dissertation; an improved automatic domain-decomposition algorithm is presented as well. The presented algorithms are applied to the simulation of practical car crash problem, and some satisfactory results have been obtained.
    The dissertation consists of several parts as follows:
     At first, it is required to ensure the computational model containing many complex factors fully compatible, in order to carry out the numerical simulation of the impact response of such large-scale complex structural efficiently. Therefore it is started with the derivation of variational equation, full formulations including contact boundary conditions, internal forces of shell element are given, and the algorithms for contact-surfaces searching, contact-force computation, and even time integration for the response computation are listed as well. The computational model formulated is fully compatible, and numerical examples have shown rather high efficiency.
    Based on domain decomposition method, parallel algorithms for internal force computation, contact searching and contact force determination are developed, in which the domain decomposition approach on element level is adopted for both internal and contact force computation, and in this way the incompatibility of two parts of parallel computation encountered in literature has been avoided. The numerical examples have shown that the parallel algorithm presented for contact-impact simulation on a PC cluster exhibits good parallel efficiency and scalability. A new Modified Greedy Algorithm is presented in this paper which can obtain better length to width ratio through considering the information of nodes
    
    coordinate. The numerical examples have shown that the algorithm presented gives satisfactory results for several different meshes
    Finally, the large-scale parallel computation of car crash simulation is carried out on a PC cluster using the presented numerical model and algorithms. Dual dynamic domain decomposition technique is integrated into parallel algorithm, and the domain decomposition both for internal force computation and contact force computation is accomplished on element level, in order to keep the consistency of computational model. The simulation results of practical car case- and car-crash, in comparison with the corresponding experimental results, show that the numerical simulation is reasonable, the variation tendence of response curves and some key values of the numerical and experimental results at some key points have shown good agreement. In comparison with the computation on single PC, the parallel computing on PC cluster can reduce computing time significantly, and has good scalability. On a PC cluster with 8 nodes, the speedup can approximately reach 5.5, and for the whole car crash simulation of 150000 DOFs and 160000 time steps takes the computing time of 7.26 hours. In this way, the parallel computing on PC cluster consisted of 8 nodes can be applied to the numerical simulation of practical car crashworthiness.
引文
[1] Hibbitt H D, Marcal P V and Rice J R, A finite element formulation for problems of large strain and large displacement, Int J Solids Structures, 1970, 6: 1069-1086
    [2] Bathe K J, Ramm E and Wilson E L, Finite element formulations for large deformation dynamic analysis, Int J Nume Meth Engng, 1975, 9: 353-386
    [3] Bathe K J, Bolourchi S, A geometric and material nonlinear plae and shell element, Computers and structures, 1979, 11: 23-48
    [4] Key A W, HONDO -A finite element computer program for the large deformation dynamic response of axisymmetric solids, Sandia National laboratories, Albuquerque, NM, Rept No. 74-0039,1974
    [5] Key A W, A finite element procedure for large deformation dynamic response of axisymmetric solids, Comput Meth Appl Mech Eng, 1974, 4: 195-218
    [6] Yagawa G and Kanto Y, Finite element analysis of contact problems using penalty function method, In: Computational Methods in Contact mechanics, editors Aliabadi M H and Brebbia C A, 1993, 67-78
    [7] Bathe K J, Chaudhary A, Solution method for planar and axisymmetric contact problems, Int J Nume mech Engng, 1985, 21(1): 65-88
    [8] Hughes T J R and Taylor R L, A finite element method for a class of contact-impact problems, Comput Meth Appl Mech Engng, 1976, 8:249-276
    [9] Belytschko T, Lin J L, Tsay C S, Explicit algorithms for the nonlinear dynamics of shells, Comput Meth Appl Mech Engng, 1984, 42:225-251
    [10] Hallquist J O Goudreau G L and Benson D J, Sliding interfaces with contact-impact in large scale Lagrangian computations, Comput Meth Appl Mech Engng, 1984, 51:107-137
    [11] Zhong Z H, On contact-impact problems, Dissertation No.178, Linkoping: Linkoping University, 1988
    [12] Ahmad S,Irons B M and Zienkiewicz O C, Analysis of thick and thin shell structures by curved finite elements, Int J Nume Meth Engng, 1970, 2: 419-451
    [13] Ramm E, A plate/shell element for large deflections and rotations, In: Formulations and Computational Algorithms in Finite Element Analysis, Bathe K J, Oden J T and Wunderlich W(eds), MIT Press, 1977
    
    
    [14] Hughes T J R and Liu W K, Nonlinear finite element analysis of shells: Part I. Three-dimensional shells, Comput Meth Appl Mech Engng, 1981, 26: 331-362
    [15] Belytschko T, Wong B L and Chiang H Y, Advances in one-point quadrature shell elements, Comput Meth Appl Mech Engng, 1992, 96: 93-107
    [16] Dienes J K, On the analysis of rotation and stress rate in deformation bodies, Acta Mech, 1979, 32: 217-232
    [17] Atluri S N, Alternate stress and conjugate strain measures and mixed variational formulations involving rigid rotations for computational analyses of finitely deformed solid with applications to plates and shells, Comput Meth Appl Mech Engng, 1984, 8: 137-171
    [18] Johnson G C and Bammann D J, A discussion of stress rates in finite deformation problems, Int J Solids Structures, 1984, 20(8): 725-737,
    [19] Wilkins M L, Calculation of elastic-plastic flow, Methods in computational physics, In: Advances in research and applications, Vol 3 (ed.Alder B, Fernback S and Rotenberg M), Academic Press, New York, 1964: 211-263
    [20] Krieg R D and Krieg D B, Accuracies of numerical solution methods for the elastic-perpectly plastic model, J. of Pressure Vessel Tech, Tran. Of the ASME, 1977: 510-515
    [21] Simo J C and Taylor R L, A return mapping algorithm for plane stress elastoplasticity, Int. J. Nume. Meth. Engng., 1986, 22: 649-670
    [22] Matthies H and Strang G, The solution of nonlinear finite element equations, Int. J. Nume. Meth. Engng., 1979, 14: 1613-1626
    [23] Newmark N M, A method of computation for structural dynamics. J. Engng. Mech. Div., ASCE 85, 1959: 67-94
    [24] Wilson E L, Farhoomand I and Bathe K J, Nonlinear dynamic analysis of complex structures, Earthquake Engineering and Structural Dynamics, 1973, 1: 241-252
    [25] Hilber H M, Hughes T J R and Taylor R L, Improved numerical dissipation for time integration algorithms in structural dynamics, Earthquake Engineering and Structural Dynamics, 1977, 5: 283-292
    [26] Belytschko T, A survey of numerical methods and computer programs for dynamic structural analysis, Nuclear Engineering and Design, 1976, 37: 23-34
    [27] Goudreau G L and Hallquist J O, Recent developments in large-scale finite element Lagrangian hydrocode technology, Comput. Meth. Appl. Mech. Engng., 1982, 33: 725-757
    [28] Hallquist J O, DYNA3D course notes, Tech.. Rep. UCID-19899, Rev. 2, University of California, Lawrence Livermore National Laboratory, 1987
    Hallquist J O, NIKE3D: An implicit, finite deformation, finite element code for analyzing the
    
    [29] static and dynamic response of three-dimensional solids, Tech.. Rep. UCID-18822, Rev. 1, University of California, Lawrence Livermore National Laboratory, 1984
    [30] Bertholf L D and Benzley S E, TOODY II, A computer program for two-dimensional wave propagation, Sandia National Laboratories, Albuquerque, NM, Rept. SC-RR, 1968: 68-41
    [31] Maenchen G and Sack S, The TENSOR code, in: Alder B, Methods in Computational Physics, 1964, 3: 181-210
    [32] HKS Inc. ABAQUS Theory Manual, Version 5.5, 1996
    [33] HKS Inc. ABAQUS/Explicit User's Manual, Version 5.6, 1996
    [34] Benson DJ and Hallquist JO. A single surface contact algorithm for the post-buckling analysis of shell structures. Computer Methods and Applied Mechanics, 1990, 78: 141~150
    [35] 张汝清等. 并行计算结构力学. 重庆:重庆大学出版社,1993
    [36] Noor AK. New computing systems and future high-performance computing environment and their impact on structural analysis and design. Computers and Structures, 1997, 64(1): 1~30
    [37] Mackerle J. Parallel fnite element and boundary element analysis: theory and applications: A bibliography (1997~1999). Finite Elements in Analysis and Design, 2000, 35: 283~296
    [38] Law K H. A parallel finite element solution method. Computers and Structures,1986,23(6):845~858
    [39] Lui,E.M. Zhang,W.P. Parallel frontal solution for large-scale structure analysis. In: Proceedings of the 10th Conference on Electronic Computation. 1991. 329~336
    [40] Chiang KN and Fulton RE. Structural dynamics methods for concurrent processing computers. Computers and Structures, 1990, 36(6):1031~1037
    [41] C. Farhat,F.X. Roux. A method of finite element tearing and interconnecting and its parallel solution algorithm. International Journal for Numerical Methods in Engineering,1991,32:1205~1227
    [42] C. Farhat,L. Crivelli. A transient FETI methodology for large-scale parallel implicit computations in structural mechanics. International Journal for Numerical Methods in Engineering,1994,37:1945~1975
    [43] Yagawa, G. Large scale finite element analysis using domain decomposition method on a parallel computer. Computers and Structures,1991,38(5):615~625
    [44] Yagawa, G. Parallel finite element method with a supercomputer network. Computers and Structures,1993,47(3):407~418
    [45] M. EL Attar. Finite element analysis on distributed memory architectures. Applied Mathematics and Computation,1992,52:309~316
    
    
    [46] A. Meyer, Chemnitz. A parallel preconditioned conjugate gradient method using domain decomposition and inexact solvers on each subdomain. Computing, 1995, 45: 217~234
    [47] A. I. Khan,B. H. V. Topping. Parallel finite element analysis using Jacobi-conditioned conjugate gradient algorithm. Advances in Engineering Software,1996,25:309~319
    [48] Hojjat Adeli. Parallel processing in computational mechanics. Marcel Dekker Inc., 1992
    [49] Hojjat Adeli,Sanjay Kumar. Distributed computer-aided engineering. LLC:CRC Press,1999
    [50] H.S. Chada,J.W. Baugh Jr. Network-distributed finite element analysis. Advances in Engineering Software,1996,25:267~280
    [51] Plaskacz EJ. Parallel finite-element analysis via message passing. Microcomputers in Civil Engineering, 1997, 12(2): 101~118
    [52] 周树荃等. 有限元结构分析并行计算. 北京:科学出版社,1994
    [53] 周树荃,曾岚. 有限元方程组的并行EBE预处理共轭梯度法. 见:全国第四届并行算法学术会议论文集. 1993
    [54] 程建钢,李明瑞,黄文彬. 有限元分析的并行计算方法. 北京农业工程大学学报,1994,14(2):5~12
    [55] 程建钢,姚振汉,李明瑞.结构动力分析显式积分并行算法与实现.清华大学学报,1996,36(10): 80~85
    [56] 姚振汉,程建钢.并行计算模型与有限元并行算法设计.力学与工程应用,1996,6(9): 58~65
    [57] 王希诚,一种全耦合多相流分析的并行计算方法,力学学报,1999,3:45-52
    [58] 王希诚,一种粗粒度并行遗传算法及其应用,计算力学学报,2002,2:17-21
    [59] Belytschko T and Neal M O. Contact-impact by the pinball algorithm with penalty and Langrangian methods. International Journal for Numerical Methods in Engineering, 1991, 31: 547~572
    [60] Malone JG and Johnson NL. A parallel finite-element contact/impact algorithm for nonlinear explicit transient analysis, Part1: The search algorithm and contact mechanics. International Journal for Numerical Methods in Engineering, 1994, 37(4): 559~590
    [61] Malone JG and Johnson NL. A parallel finite-element contact/impact algorithm for nonlinear explicit transient analysis. Part2: Parallel implementation. International Journal for Numerical Methods in Engineering, 1994, 37(4): 591~603
    [62] Zhong ZH and Nilsson L. Contact-impact algorithms on parallel computers. Nuclear Engineering and Design, 1994, 150(2-3): 253~263
    Namburu RR, Turner DA and Tamma KK. Effective data parallel self-starting explicit
    
    [63] methodology for computational structural dynamics on the Connection Machine CM-5. Int. J. Numer. Meth. Engng, 1995, 38(19): 3211~3226
    [64] Danielson KT, Namburu RR. Nonlinear dynamic finite element analysis on parallel computers using FORTRAN 90 and MPI. Advances in Engineering Software, 1998, 29(3-6): 179~186
    [65] Watson BC, Noor AK. Large-scale contact/impact simulation and sensitivity analysis on distributed-memory computers. Comput. Methods Appl. Mech. Engrg, 1997, 141(3-4): 373~388
    [66] Attaway SW, Hendrickson BA, Plimpton SJ, et al.. Parallel contact detection algorithm for transient solid dynamics simulations using PRONTO3D. Computational Mechanics, 1998, 22(2): 143~159
    [67] Brown K, Attaway S, Plimpton S, et al.. Parallel strategies for crash and impact simulations. Comput. Methods Appl. Mech. Engrg., 2000, 184: 375~390
    [68] Nikishkov GP, Kawka M, Makinouchi A, et al.. Porting an industrial sheet metal forming code to a distributed memory parallel computer, Computers and Structures, 1998, 67: 439~449
    [69] Krysl P and Belytschko T. Object-oriented parallelization of explicit structural dynamics with PVM. Computers and Structures, 1998, 66(2-3): 259~273
    [70] Charbel Farhat. A simple and efficient automatic FEM domain decomposer, Computers and Structures,1988,28(5):579~602
    [71] C. Farhat,M. Lesoinne. Mesh partitioning algorithms for the parallel solution of partial differential equations. Applied Numerical Mathematics,1993,12:443~457
    [72] Charbel Farhat,Michel Lesoinne. Automatic partitioning of unstructured meshes for the parallel solution of problems in computational mechanics. International Journal for Numerical Methods in Engineering,1993,36:745~764
    [73] W. Rachowicz. An overlapping domain decomposition preconditioner for an anisotropic h-adaptive finite element method. Computer methods in applied mechanics and engineering,1995,127:269~292
    [74] Shang-Hsien Hsieh. Evaluation of automatic domain partitioning algorithms for parallel finite element analysis. International Journal for Numerical Methods in Engineering,1997,40:1025~1051
    [75] Shang-Hsien Hsieh,Glaucio H. Paulino,John F. Abel. Recursive spectral algorithms for automatic domain partitioning in parallel finite element analysis. Computer Methods in Appied Mechanics and Engineering,1995,121:137~162
    
    
    [76] Bruce Hendrickson,Tamara G. Kolda. Graph partitioning models for parallel computing. Parallel Computing,2000,26:1519~1534
    [77] Simon H D, Partitioning of unstructured problems for parallel processing, Comput.Systems.Eng., 2, 135-148, 1991
    [78] G. Karypis,V. Kumar. A fast and high quality multilevel scheme for partitioning irregular graphs. SIAM J. Sci. Comput.,1998,26(2):215~230
    [79] B. Hendrickson,R. Leland. The Chaco User's Guide: Version 2.0. Technical Report SAND94-2692, Sandia National Laboratories, Albuquerque, NM, 1994
    [80] A. Kaveh,A. Bahreininejad,H. Mostafaei. A hybrid graph-neural method for domain decomposition. Computers and Structures,1999,70:667~674
    [81] Frederik Jan Lingen. A versatile load balancing framework for parallel applications based on domain decomposition. International Journal for Numerical Methods in Engineering,2000,49:1431~1454
    [82] Kamal M M, Analysis and simulation of Vehicle to Barrier Impact, SAE Paper 700414, Detroit, MI, 1970
    [83] Trai M and Emori RI. A study on automobile crashworthiness. SAE Paper 700175, 1970
    [84] Nikravesh PE, Chung IS and Benedict RL. Plastic hinge approach to vehicle crash simulation. Computers and Structures, 1983, 16(1-4):395~400
    [85] Belytschko T, On computational methods for crashworthiness, Comput.Struct., 42(2),271-279,1992
    [86] Hallquist JO. LS-DYNA3D Theoretical Manual, Rev.2. Livermore: Livermore Software Technology Corporation, 1993
    [87] Hallquist JO. LS-DYNA3D User's Manual, Ver 940. Livermore: Livermore Software Technology Corporation, 1998
    [88] Whirley RG and Engelmann BE. Automatic contact in DYNA3D for vehicle crashworthiness. Crashworthhiness and Occupant Protection in Transportation Systems, Proceedings of the 1993 ASME Winter Annual Meeting, ASME Applied Mechanics Division, 1993, 15~29
    [89] Schweizerhof K, Nilsson L and Hallquist JO. Crashworthiness analysis in the automotive industry, International Jurnal of Computer Applications in Technology, 1992, 5(2-4): 134~156
    [90] Haug E, Clinckemaillie J and Ni XM. 汽车碰撞仿真与设计的最新进展和发展趋势. 机械工程学报, 1998, 34(1): 93~99
    [91] Schauer DA, Hoover CG, Kay GJ, et al.. Crashworthiness simulations with DYNA3D. Transportation Research Record, No.1528, 1996, 124~129
    
    
    [92] Elsner B, Galbas HG, Gorg B, et al.. A parallel multi-level approach for contact problems in crashworthiness simulation, 3rd International Conference in Computational Structures Technology, Budapest, Hungary, 1996
    [93] Lonsdale G, Petitet F and Zimmermann F. Programming crashworthiness Simulation for Parallel platform, Mathematical and Computer Modelling, 2000, 31: 61~76
    [94] 黄世霖,张金换,王晓冬,汽车碰撞与安全,清华大学出版社,2000
    [95] 钟志华. 汽车耐撞性分析的有限元法. 汽车工程, 1994, 16(1): 1~6
    [96] 林逸, 郭九大, 王望予. 汽车被动安全性研究综述. 汽车工程, 1998, 20(1): 1~9
    [97] 陈国良,并行计算——结构、算法、编程. 北京:高等教育出版社,1999.10
    [98] Hwang K and Xu Z. Scalable parallel computing: technology, architecture, programming. Beijing: China Mechanical Industry Press, 1999
    [99] Geist A, Beguelin A, Dongarra J, et al.. PVM: Parallel Virtual Machine - A User's Guide and Tutorial for Network Parallel Computing. MIT Press, Cambridge, MA, 1994
    [100] Geist A, Beguelin A, Dongarra J, et al.. PVM3 User's Guide and Reference Manual. Oak Ridge National Laboratory, 1994
    [101] Gropp W, Lusk E and Skjellum A. Using MPI - Portable, Parallel Programming with the Message-Passing System. MIT Press, Cambridge, MA, 1995
    [102] M. Fiedler. A property of eigenvectors of nonnegative symmetric matrices and its application to graph theory. Czechoslovak Math. J.,1975,25:607~618
    [103] C. Walshaw,M. Cross,M.G. Everett. A localised algorithm for optimising unstructured mesh partitions. Int. J. Supercomput. Appl.,1995,9(4):280~295
    [104] Frederik Jan Lingen. A versatile load balancing framework for parallel applications based on domain decomposition. International Journal for Numerical Methods in Engineering,2000,49:1431~1454
    [105] B. Hendrickson,R. Leland. The Chaco User's Guide: Version 2.0. Technical Report SAND94-2692, Sandia National Laboratories, Albuquerque, NM, 1994
    [106] A. Kaveh,A. Bahreininejad,H. Mostafaei. A hybrid graph-neural method for domain decomposition. Computers and Structures,1999,70:667~674
    [107] 王春雨. 应用有限元法研究碰撞过程中车架结构的变形及动态响应: [硕士学位论文]. 北京:清华大学汽车工程系, 1996
    [108] N. Touheed,P. Selwood,P.K. Jimack, et al. A comparison of some dynamic load-balancing algorithms for a parallel adaptive flow solver. Parallel Computing,2000, 26:1535~1554
    Arjen S. A framework for dynamic load balancing: A case study on explosive containment
    
    [109] simulation. Parallel Computing, 2000, 26: 737~751
    [110] 王福军. 冲击接触问题有限元法并行计算及其工程应用:[博士学位论文]. 北京:清华大学工程力学系,2000
    [111] Wang Fujun, Cheng Jiangang, Yao Zhenhan. A contact searching algorithm for contact impact problems. ACTA MECHANICA SINICA, 2000, 16(4): 374~382

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700