Reduced integration with scaled boundary parametrization for virtual elements at finite strains
有限应变下基于缩放边界参数化的虚拟单元减缩积分
Njomza Pacolli, Bjorn Sauren, Jannick Kehls, Sven Klinkel, Stefanie Reese, Hagen Holthusen
AI总结 提出一种基于减缩积分与缩放边界参数化的虚拟单元法稳定技术,通过泰勒展开实现弱形式解析积分,仅需每段一个积分点,数值算例验证了精度。
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本文提出了一种基于减缩积分与缩放边界参数化的虚拟单元法(VEM)替代稳定技术。为此,对截面中心的本构量进行泰勒级数展开,实现了弱形式的解析积分,并将每段所需的积分点减少至仅一个。通过多个数值算例(包括非线性分片测试)展示了所提公式的精度。考虑了不同加载条件(如大变形压缩)和材料条件(如超弹性各向异性和弹塑性)。使用双二次Serendipity有限元公式(Q2)和带沙漏稳定的低阶有限元公式(Q1STc+)进行比较。虽然高阶形函数未满足分片测试,但该公式得到了良好结果并能准确捕捉结构响应。此外,当物理单元类似于预分配母单元时,该公式表现更佳。弹塑性材料行为下的非对称缺口试件算例表明,所提公式能够捕捉非弹性行为。
This contribution presents an alternative stabilization technique for the virtual element method (VEM) based on reduced integration combined with a scaled boundary parametrization. To this end, a Taylor series expansion of the constitutive quantities with respect to the sectional center is carried out, enabling analytical integration of the weak form and reducing the need for integration points to only one per section. The accuracy of the proposed formulation is shown by several numerical examples, including a non-linear patch test. Different loading, e.g. compression under large deformations, and material conditions, such as hyperelastic anisotropy and elasto-plasticity, are considered. The biquadratic serendipity finite element formulation (Q2) and the low-order finite element formulation with hourglass stabilization (Q1STc+) are used for comparison. While the patch test was not fulfilled using higher order shape functions, the formulation led to good results and was able to capture the structure's response accurately. Furthermore, the formulation performed better when the physical element resembled the pre-assigned parent elements. The example of the asymmetrically notched specimen under elasto-plastic material behavior showed that the proposed formulation is able to capture inelasticities.