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arXiv 2401.06280math.NAcs.NA
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用于可压缩与近不可压缩线弹性问题的六节点三角形网格应力杂交虚拟单元法

Stress-hybrid virtual element method on six-noded triangular meshes for compressible and nearly-incompressible linear elasticity

Alvin Chen, Joseph E. Bishop, N. Sukumar

AI总结:

针对可压缩与近不可压缩线弹性问题,提出六节点三角形网格上的 SH-VEM 及罚形式 PSH-VEM,并通过基准测试验证其最优或更快的收敛性能。

摘要:

本文提出了一种在线性平面弹性问题中基于六节点三角形网格的一阶应力杂交虚拟单元法(SH-VEM)。我们采用 Hellinger–Reissner 变分原理来构造弱平衡条件和基于应力的投影算子。将散度定理应用于弱应变–位移关系后,应力投影算子以节点位移表示,从而得到一种基于位移的格式。这种应力杂交方法假定位移场全局连续,而应力场在各单元之间不连续。应力场最初由基于 Airy 应力函数的无散度张量多项式表示。然而,为了在选择基函数时具有灵活性,我们还提出了一种使用罚项来强制满足单元平衡条件的格式。该方法被称为罚应力杂交虚拟单元法(PSH-VEM)。文中给出了 PSH-VEM 和 SH-VEM 的数值结果,并在线弹性基准问题上将它们的收敛性与复合三角形 FEM 和 B-bar VEM 进行了比较。SH-VEM 在位移的 L² 范数、能量半范数以及静水应力的 L² 范数下均达到最优收敛。此外,结果表明,PSH-VEM 在大多数情况下以快于预期最优收敛率的速度收敛,但它需要选取适当的罚参数。

英文摘要:

In this paper, we present a first-order Stress-Hybrid Virtual Element Method (SH-VEM) on six-noded triangular meshes for linear plane elasticity. We adopt the Hellinger--Reissner variational principle to construct a weak equilibrium condition and a stress based projection operator. On applying the divergence theorem to the weak strain-displacement relations, the stress projection operator is expressed in terms of the nodal displacements, which leads to a displacement-based formulation. This stress-hybrid approach assumes a globally continuous displacement field while the stress field is discontinuous across each element. The stress field is initially represented by divergence-free tensor polynomials based on Airy stress functions. However, for flexibility in choosing basis functions, we also present a formulation that uses a penalty term to enforce the element equilibrium conditions. This method is referred to as the Penalty Stress-Hybrid Virtual Element Method (PSH-VEM). Numerical results are presented for PSH-VEM and SH-VEM, and we compare their convergence to the composite triangle FEM and B-bar VEM on benchmark problems in linear elasticity. The SH-VEM converges optimally in the $L^2$ norm of the displacement, energy seminorm, and the $L^2$ norm of hydrostatic stress. Furthermore, the results reveal that PSH-VEM converges in most cases at a faster rate than the expected optimal rate, but it requires the selection of a suitably chosen penalty parameter.

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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