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arXiv 2109.01491math.NAcs.CEcs.NA
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三维非线性弹性力学的有限元外演算混合法

A mixed method for 3D nonlinear elasticity using finite element exterior calculus

Bensingh Dhas, Jamun Kumar, Debasish Roy, J N Reddy

摘要:

本文讨论了一种基于Hu-Washizu(HW)型变分原理的三维非线性弹性力学混合有限元方法。在这里,变形的配置和从它的余切丛的部分被视为额外的输入参数。HW泛函的临界点除了机械平衡和本构关系之外,还强制这些截面与配置的兼容性。本FE近似区分一个向量从1-从,一个功能不常见的FE近似。这种观点使我们能够构造性能优越的有限元。利用有限元外演算的思想,构造了变分原理中微分形式的离散逼近。通过对离散泛函关于适当的自由度进行外化,得到了描述力学平衡、协调性和本构规则的离散方程,然后用牛顿法求解。然后将这种混合有限元技术应用于基准问题,其中传统的基于位移的近似遇到锁定和棋盘。

英文摘要:

This article discusses a mixed FE technique for 3D nonlinear elasticity using a Hu-Washizu (HW) type variational principle. Here, the deformed configuration and sections from its cotangent bundle are taken as additional input arguments. The critical points of the HW functional enforce compatibility of these sections with the configuration, in addition to mechanical equilibrium and constitutive relations. The present FE approximation distinguishes a vector from a 1-from, a feature not commonly found in FE approximations. This point of view permits us to construct finite elements with vastly superior performance. Discrete approximations for the differential forms appearing in the variational principle are constructed with ideas borrowed from finite element exterior calculus. The discrete equations describing mechanical equilibrium, compatibility and constitutive rule, are obtained by extemizing the discrete functional with respect to appropriate DoF, which are then solved using the Newton's method. This mixed FE technique is then applied to benchmark problems wherein conventional displacement based approximations encounter locking and checker boarding.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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