非线性有限元模拟中的应力、应变关系

提出一种方法,可以确定直至结构破坏时,与单元长度相关的应力、应变关系,并适用于有限元分析模型。采用已测出的表面位移计算结构直至破坏时的应变。从颈缩处已测出的力和横截面面积可以推导出应力的数值。此外,由于光学测量的数字特性,将应变的参考长度清晰地定义为像素的函数。在数值模拟中有限单元的长度与这个参考长度相等。此法可以对拉伸试验进行精确的数值模拟,除非在结构破坏时曲线无法拟合,或者缺少根据所取的分隔尺寸来调整材料关系的迭代方法。精确的材料关系有助于提高非线性数值模拟的准确性。

Strain and Stress Relation for Non-Linear Finite Element Simulations

This paper presents a procedure to determine an element-length dependent strain and stress relation until fracture that is suitable for implementation in finite element models. This material relation is obtained experimentally with an optical measuring system. The strain until fracture is calculated from the measured surface displacements. The stress is derived from the measured force and the cross-sectional area in the necking region. Furthermore, because of the digital nature of the optical measurements, ...