10 research outputs found

    The Challenge of Computational Mechanics

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    Equilibrated patch recovery error estimates: simple and accurate upper bounds of the error

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    [EN] This paper introduces a new recovery-type error estimator ensuring local equilibrium and yielding a guaranteed upper bound of the error. The upper bound property requires the recovered solution to be both statically equilibrated and continuous. The equilibrium is obtained locally (patch-by-patch) and the continuity is enforced by a postprocessing based on the partition of the unity concept. This postprocess is expected to preserve the features of the locally equilibrated stress field. Nevertheless, the postprocess phase modifies the equilibrium, which is no longer exactly fulfilled. A new methodology is introduced that yields upper bound estimates by taking into account this lack of equilibrium. This requires computing the L-2 norm of the error or relating it with the energy norm. The guaranteed upper bounds are obtained by using a pessimistic bound of the error L-2 norm, derived from an eigenvalue problem. Nevertheless, these bounds are not sharp. An additional strategy based on a more accurate assessment of the error L-2 norm is introduced, providing sharp estimates, which are practical upper bounds as it is demonstrated in the numerical tests.Contract/grant sponsor: Ministerio de Educación y Ciencia; contract/grant numbers: DPI2004-03000, CGL2004-06171-C03-01/CLI, DPI2004-07782-C02-02 Contract/grant sponsor: Universidad Politécnica de Valencia and Generalitat ValencianaDíez, P.; Ródenas, JJ.; Zienkiewicz, OC. (2007). Equilibrated patch recovery error estimates: simple and accurate upper bounds of the error. International Journal for Numerical Methods in Engineering. 69(10):2075-2098. https://doi.org/10.1002/nme.1837S207520986910. A Posteriori Error Estimation in Finite Element Analysis. Wiley: Chichester, 2000.. Adaptive Finite Element Methods for Differential Equations. Birkhäuser: Basel, 2003.Zienkiewicz, O. C., & Zhu, J. Z. (1987). A simple error estimator and adaptive procedure for practical engineerng analysis. International Journal for Numerical Methods in Engineering, 24(2), 337-357. doi:10.1002/nme.1620240206Zienkiewicz, O. C., & Zhu, J. Z. (1992). The superconvergent patch recovery (SPR) and adaptive finite element refinement. Computer Methods in Applied Mechanics and Engineering, 101(1-3), 207-224. doi:10.1016/0045-7825(92)90023-dZienkiewicz, O. C., & Zhu, J. Z. (1992). The superconvergent patch recovery anda posteriori error estimates. Part 1: The recovery technique. International Journal for Numerical Methods in Engineering, 33(7), 1331-1364. doi:10.1002/nme.1620330702Zienkiewicz, O. C., & Zhu, J. Z. (1992). The superconvergent patch recovery anda posteriori error estimates. Part 2: Error estimates and adaptivity. International Journal for Numerical Methods in Engineering, 33(7), 1365-1382. doi:10.1002/nme.1620330703Babuška, I., Strouboulis, T., & Upadhyay, C. . (1994). A model study of the quality of a posteriori error estimators for linear elliptic problems. Error estimation in the interior of patchwise uniform grids of triangles. Computer Methods in Applied Mechanics and Engineering, 114(3-4), 307-378. doi:10.1016/0045-7825(94)90177-5Babuška, I., Strouboulis, T., Upadhyay, C. S., Gangaraj, S. K., & Copps, K. (1994). Validation ofa posteriori error estimators by numerical approach. International Journal for Numerical Methods in Engineering, 37(7), 1073-1123. doi:10.1002/nme.1620370702Díez, P., JoséEgozcue, J., & Huerta, A. (1998). A posteriori error estimation for standard finite element analysis. Computer Methods in Applied Mechanics and Engineering, 163(1-4), 141-157. doi:10.1016/s0045-7825(98)00009-7Díez, P., Parés, N., & Huerta, A. (2003). Recovering lower bounds of the error by postprocessing implicit residuala posteriorierror estimates. International Journal for Numerical Methods in Engineering, 56(10), 1465-1488. doi:10.1002/nme.620Wiberg, N.-E., & Abdulwahab, F. (1993). Patch recovery based on superconvergent derivatives and equilibrium. International Journal for Numerical Methods in Engineering, 36(16), 2703-2724. doi:10.1002/nme.1620361603Wiberg, N.-E., Abdulwahab, F., & Ziukas, S. (1994). Enhanced superconvergent patch recovery incorporating equilibrium and boundary conditions. International Journal for Numerical Methods in Engineering, 37(20), 3417-3440. doi:10.1002/nme.1620372003Blacker, T., & Belytschko, T. (1994). Superconvergent patch recovery with equilibrium and conjoint interpolant enhancements. International Journal for Numerical Methods in Engineering, 37(3), 517-536. doi:10.1002/nme.1620370309Ramsay, A. C. A., & Maunder, E. A. W. (1996). Effective error sttimation from continous, boundary admissible estimated stress fields. Computers & Structures, 61(2), 331-343. doi:10.1016/0045-7949(96)00034-xLEE, T., PARK, H. C., & LEE, S. W. (1997). A SUPERCONVERGENT STRESS RECOVERY TECHNIQUE WITH EQUILIBRIUM CONSTRAINT. International Journal for Numerical Methods in Engineering, 40(6), 1139-1160. doi:10.1002/(sici)1097-0207(19970330)40:63.0.co;2-0Aalto, J. (1997). Built-in field equations for recovery procedures. Computers & Structures, 64(1-4), 157-176. doi:10.1016/s0045-7949(96)00159-9Aalto, J., & Isoherranen, H. (1997). An element by element recovery method with built-in field equations. Computers & Structures, 64(1-4), 177-196. doi:10.1016/s0045-7949(96)00155-1Aalto, J., & Perälä, M. (1999). Built-in field equations for patch recovery procedures using weighted residuals. Computers & Structures, 73(1-5), 91-118. doi:10.1016/s0045-7949(98)00283-1Aalto, J., & Åman, M. (1999). Polynomial representations for patch recovery procedures. Computers & Structures, 73(1-5), 119-146. doi:10.1016/s0045-7949(98)00282-xBOROOMAND, B., & ZIENKIEWICZ, O. C. (1997). RECOVERY BY EQUILIBRIUM IN PATCHES (REP). International Journal for Numerical Methods in Engineering, 40(1), 137-164. doi:10.1002/(sici)1097-0207(19970115)40:13.0.co;2-5Kvamsdal, T., & Okstad, K. M. (1998). Error estimation based on Superconvergent Patch Recovery using statically admissible stress fields. International Journal for Numerical Methods in Engineering, 42(3), 443-472. doi:10.1002/(sici)1097-0207(19980615)42:33.0.co;2-gPark, H. C., Shin, S.-H., & Lee, S. W. (1999). A superconvergent stress recovery technique for accurate boundary stress extraction. International Journal for Numerical Methods in Engineering, 45(9), 1227-1242. doi:10.1002/(sici)1097-0207(19990730)45:93.0.co;2-w, , . Modification of the SPR technique to ensure the fulfillment of imposed tractions in boundary nodes. In Adaptive Modeling and Simulation, (eds), vol. I. CIMNE, 2003., , . Improvement of the superconvergent patch recovery technique by the use of constraint equations: the SPR-C technique. Preprint.Abel, J. F., & Shephard, M. S. (1979). An algorithm for multipoint constraints in finite element analysis. International Journal for Numerical Methods in Engineering, 14(3), 464-467. doi:10.1002/nme.1620140312Farhat, C., Lacour, C., & Rixen, D. (1998). Incorporation of linear multipoint constraints in substructure based iterative solvers. Part 1: a numerically scalable algorithm. International Journal for Numerical Methods in Engineering, 43(6), 997-1016. doi:10.1002/(sici)1097-0207(19981130)43:63.0.co;2-bAinsworth, M., & Oden, J. T. (1992). A procedure for a posteriori error estimation for h-p finite element methods. Computer Methods in Applied Mechanics and Engineering, 101(1-3), 73-96. doi:10.1016/0045-7825(92)90016-d. Theory of Elasticity 2nd edn.McGraw-Hill: New York, 1951.. Finite Element Analysis 1st edn.Wiley: New York, 1991

    2nd International Conference on Finite Elements in Fluids

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