اجزای محدود تطابقی دوبعدی به کمک GPGPU

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی خواجه نصیرالدین طوسی

چکیده

خطای گسسته‌سازی یکی از خطاهای رایج در روش اجزای محدود است. برای کاهش خطای گسسته‌سازی ممکن است از روش‌های تطابقی استفاده شود. روش‌های تطابقی عموماً حجم محاسبات زیادی دارند؛ یک روش‌ برای کاهش حجم این محاسبات، استفاده از عملگرهای انتقال داده است. حتی باوجود عملگرهای انتقال داده هنوز هم روش تطابقی زمان زیادی را از کاربران می‌گیرد. با توجه به امکانات و توانایی‌های جدیدی که پردازنده‌های گرافیکی به کاربران خود جهت انجام محاسبات همه‌منظوره تحت پلتفرم کودا می‌دهند و صرفه اقتصادی مناسب پردازنده‌های گرافیکی نسبت به پردازنده‌های معمولی، در این مقاله سعی شده است الگوریتمی ارائه شود که بتوان با استفاده از پردازش همه‌منظوره بر روی پردازنده‌های گرافیکی زمان انجام محاسبات را کاهش داد. الگوریتم ارائه‌شده بر اساس تحلیل اولیه اجزای محدود، با شبکه تقریبا یکنواخت شروع می‌شود و در هر مرحله بر اساس گرادیان جابه‌جایی و به‌صورت هوشمند، شبکه را ریزسازی می‌کند. الگوریتم معمول این شیوه در چند مرحله بهبود یافته است. مرحله تشکیل وصله به کمک روش  K همسایه پیاده‌سازی شده تا بتوان آن را به صورت مؤثرتر موازی نمود. در مرحله انتقال اطلاعات نیز از یک روش دینامیک جهت تعیین بهترین منحنی از دسته بهترین منحنی‌ها استفاده‌شده است. در پیاده‌سازی ایده‌ها از زبان پایتون استفاده‌شده است تا مخاطب بیشتر داشته و به‌صورت کد منبع باز منتشر شود. نتایج نشان می‌دهد که میزان تسریع این الگوریتم متناسب با تعداد المان‌ها افزایش می‌یابد. به‌ عنوان ‌مثال برای مسئله‌ای با تعداد 908 المان، سرعت پردازش برای مراحل یک الی سه از تظریف به ترتیب 6.6، 9.1 و 12.7 برابر شده است. مجموع زمان مورد نیاز برای پردازش هر سه مرحله در حالت سریال 96 ثانیه بوده که با پیاده سازی این الگوریتم به 8 ثانیه کاهش یافته است. نتایج نشان می‌دهد که این نرم افزار می‌تواند برای تسریع آنالیز به روش اجزای محدود تطابقی جهت کاهش خطای گسسته‌سازی استفاده شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Two-Dimensional Adaptive Finite Element Using GPGPU

نویسندگان [English]

  • Amir Hossein Khatami
  • Saeed Asil Gharebaghi
Civil Engineering Department, K. N. Toosi University of Technology
چکیده [English]

The discretization error is one of the most common errors in the finite element method. One way to reduce this error is by using adaptive methods. Adaptive methods generally involve a large computational load; a technique for reducing this load is the use of data transfer operators. Even with data transfer operators, adaptive methods still require significant time from users. Given the new capabilities provided by graphics processing units (GPUs) for general-purpose computing under the CUDA platform, and the economic efficiency of GPUs compared to standard processors, this paper aims to present an algorithm that can reduce computation time through general-purpose GPU processing. The proposed algorithm begins with an initial finite element analysis using a nearly uniform mesh and refines the mesh intelligently at each step based on the displacement gradient. The conventional algorithm has been improved at several points. The patch formation stage is implemented using the K-nearest neighbor method to facilitate more efficient parallelization. In the data transfer stage, a dynamic method is employed to select the optimal curve from a set of the best curves. The results show that the acceleration of this algorithm increases proportionally with the number of elements. For instance, for a problem with 908 elements, the processing speed for stages one through three increased by factors of 6.6, 9.1, and 12.7, respectively. The total time required for all three stages in serial processing was 96 seconds, which was reduced to 8 seconds using this algorithm.

کلیدواژه‌ها [English]

  • Data Transfer Operator
  • Adaptive Finite Element Method
  • GPU
  • GPGPU
  • KNN
[1] O.C. Zienkiewicz, J.Z. Zhu, A simple error estimator and adaptive procedure for practical engineerng analysis, in, 1987, pp. 337-357.
[2] L.Y. Li, P. Bettess, J.W. Bull, T. Bond, I. Applegarth, Theoretical formulations for adaptive finite element computations, Communications in Numerical Methods in Engineering, 11(10) (1995) 857-868.
[3] J. Grandy, Conservative remapping and region overlays by intersecting arbitrary polyhedra, Journal of Computational Physics, 148(2) (1999) 433-466.
[4] X. Jiao, M.T. Heath, Common‐refinement‐based data transfer between non‐matching meshes in multiphysics simulations, International Journal for Numerical Methods in Engineering, 61(14) (2004) 2402-2427.
[5] T. Arbogast, L.C. Cowsar, M.F. Wheeler, I. Yotov, Mixed finite element methods on nonmatching multiblock grids, SIAM Journal on Numerical Analysis, 37(4) (2000) 1295-1315.
[6] M.M. Rashid, Material state remapping in computational solid mechanics, International Journal for Numerical Methods in Engineering, 55 (2002) 431-450.
[7] M. Ortiz, J.J. Quigley IV, Adaptive mesh refinement in strain localization problems, Computer Methods in Applied Mechanics and Engineering, 90 (1991) 781-804.
[8] G.T. Camacho, M. Ortiz, Computational modelling of impact damage in brittle materials, International Journal of solids and structures, 33(20-22) (1996) 2899-2938.
[9] N.-S. Lee, K.-J. Bathe, Error indicators and adaptive remeshing in large deformation finite element analysis, Finite Elements in Analysis and Design, 16(2) (1994) 99-139.
[10] B. Boroomand, O.C. Zienkiewicz, Recovery procedures in error estimation and adaptivity. Part II: Adaptivity in nonlinear problems of elasto-plasticity behaviour, Computer Methods in Applied Mechanics and Engineering, 176 (1999) 127-146.
[11] M. Kitamura, H. Gu, H. Nobukawa, A study of applying the superconvergent patch recovery (SPR) method to large deformation problem, Journal of the Society of Naval Architects of Japan, 2000(187) (2000) 201-208.
[12] X. Tang, T. Sato, Adaptive mesh refinement and error estimate for 3-D seismic analysis of liquefiable soil considering large deformation, Journal of natural disaster science, 26(1) (2004) 37-48.
[13] H. Gu, Z. Zong, K.C. Hung, A modified superconvergent patch recovery method and its application to large deformation problems, Finite Elements in Analysis and Design, 40 (2004) 665-687.
[14] A. Khoei, S. Gharehbaghi, Modelling of localized plastic deformation via the adaptive mesh refinement, International Journal of Nonlinear Sciences and Numerical Simulation, 4(1) (2003) 31-46.
[15] S.A. Gharehbaghi, A.R. Khoei, Three-dimensional superconvergent patch recovery method and its application to data transferring in small-strain plasticity, Computational Mechanics, 41 (2008) 293-312.
[16] A.R. Khoei, S.A. Gharehbaghi, Three-dimensional data transfer operators in large plasticity deformations using modified-SPR technique, Applied Mathematical Modelling, 33 (2009) 3269-3285.
[17] A.R. Khoei, S.A. Gharehbaghi, A.R. Tabarraie, A. Riahi, Error estimation, adaptivity and data transfer in enriched plasticity continua to analysis of shear band localization, Applied Mathematical Modelling, 31 (2007) 983-1000.
[18] A.R. Khoei, S.A. Gharehbaghi, A.R. Azami, A.R. Tabarraie, SUT-DAM: An integrated software environment for multi-disciplinary geotechnical engineering, in, Elsevier, 2006, pp. 728-753.
[19] J. Peddie, The History of the GPU - New Developments, in, Springer International Publishing, 2023, pp. 1-410.
[20] K. Proudfoot, W.R. Mark, S. Tzvetkov, P. Hanrahan, A real-time procedural shading system for programmable graphics hardware, in, Association for Computing Machinery, 2001, pp. 159-170.
[21] M. Kronbichler, K. Ljungkvist, Multigrid for Matrix-Free High-Order Finite Element Computations on Graphics Processors, in, ACM PUB27 New York, NY, USA           2019.
[22] Y. Zhang, X. Yan, X. Ren, S. Wang, D. Wu, B. Bai, Parallel implementation and branch optimization of EBE-FEM based on CUDA platform, in, 2020, pp. 595-600.
[23] J. Zhang, D. Shen, GPU-based implementation of finite element method for elasticity using CUDA, in, IEEE Computer Society, 2014, pp. 1003-1008.
[24] S.A. Gharehbaghi, A.R. Khoei, Three-dimensional superconvergent patch recovery method and its application to data transferring in small-strain plasticity, in, Springer Verlag, 2008, pp. 293-312.
[25] O.C. Zienkiewicz, R.L. Taylor, J.Z. Zhu, , The finite element method [electronic resource] : its basis and fundamentals / O.C. Zienkiewicz, R.L. Taylor, J.Z. Zhu., in, Amsterdam ; Boston : Elsevier Butterworth-Heinemann, 2005., 2005.
[26] A.R. Khoei, A.R. Tabarraie, S.A. Gharehbaghi, H-adaptive mesh refinement for shear band localization in elasto-plasticity Cosserat continuum, in, Elsevier, 2005, pp. 253-286.
[27] A.R. Khoei, S.A. Gharehbaghi, The superconvergence patch recovery technique and data transfer operators in 3D plasticity problems, in, Elsevier, 2007, pp. 630-648.
[28] A.R. Khoei, S.A. Gharehbaghi, A.R. Tabarraie, A. Riahi, Error estimation, adaptivity and data transfer in enriched plasticity continua to analysis of shear band localization, in, Elsevier, 2007, pp. 983-1000.
[29] A.R. Khoei, S.A. Gharehbaghi, Three-dimensional data transfer operators in large plasticity deformations using modified-SPR technique, in, Elsevier, 2009, pp. 3269-3285.
[30] B. Boroomand, O.C. Zienkiewicz, Recovery procedures in error estimation and adaptivity. Part II: Adaptivity in nonlinear problems of elasto-plasticity behaviour, in, North-Holland, 1999, pp. 127-146.
[31] O.C. Zienkiewicz, B. Boroomand, J.Z. Zhu, Recovery procedures in error estimation and adaptivity Part I: Adaptivity in linear problems, Computer Methods in Applied Mechanics and Engineering, 176(1-4) (1999) 111-125.
[32] J. Barlow, Optimal stress locations in finite element models, in, John Wiley & Sons, Ltd, 1976, pp. 243-251.
[33] O.C. Zienkiewicz, J.Z. Zhu, The superconvergent patch recovery (SPR) and adaptive finite element refinement, in, 1992, pp. 207-224.
[34] O.C. Zienkiewicz, J.Z. Zhu, The superconvergent patch recovery and a posteriori error estimates. Part 2: Error estimates and adaptivity, in, John Wiley & Sons, Ltd, 1992, pp. 1365-1382.
[35] O.C. Zienkiewicz, J.Z. Zhu, The superconvergent patch recovery and a posteriori error estimates. Part 1: The recovery technique, in, John Wiley & Sons, Ltd, 1992, pp. 1331-1364.
[36] O.C. Zienkiewicz, M. Huang, M. Pastor, Localization problems in plasticity using finite elements with adaptive remeshing, in, John Wiley & Sons, Ltd, 1995, pp. 127-148.
[37] O.C. Zienkiewicz, R.L. Taylor, J.Z. Zhu, The finite element method [electronic resource] : its basis and fundamentals / O.C. Zienkiewicz, R.L. Taylor, J.Z. Zhu., in, Amsterdam ; Boston : Elsevier Butterworth-Heinemann, 2005., 2005.
[38] A.R. Khoei, Computational plasticity in powder forming processes, in, Elsevier, 2005, pp. 449.
[39] C. Geuzaine, J.F. Remacle, Gmsh: A 3-D finite element mesh generator with built-in pre- and post-processing facilities, in, John Wiley & Sons, Ltd, 2009, pp. 1309-1331.
[40] M. Cervera, N. Lafontaine, R. Rossi, M. Chiumenti, Explicit mixed strain–displacement finite elements for compressible and quasi-incompressible elasticity and plasticity, in, Springer Verlag, 2016, pp. 511-532.