A CLASS OF MIXED ASSUMED STRAIN METHODS AND THE METHOD OF INCOMPATIBLE MODES
A CLASS OF MIXED ASSUMED STRAIN METHODS AND THE METHOD OF INCOMPATIBLE MODES
复制标题
DOI：
10.1002/nme.1620290802
复制
发表时间：
1990-06-01
影响因子：
2.9
通讯作者：
RIFAI, MS
中科院分区：
文献类型：
--
作者：
SIMO, JC;RIFAI, MS
提出了一种位移、应力和增强应变场的三场混合公式，作为一种特殊情况，它包含了经典的非协调模式方法。在这个框架中，非协调单元作为增强应变场的特殊“协调”混合近似而出现。应力插值包含分段常数函数和与增强应变插值的L2-正交的条件，确保满足贴片试验，并允许从公式中消除应力场。上述条件是以特别便于元件设计的形式表示的。作为一个说明的方法，三个新的元素被开发，并表现出良好的性能：一个平面三维弹性/塑性QUAD，轴对称元素和厚板弯曲QUAD。本文所述的公式适用于非线性分析。
A three‐field mixed formulation in terms of displacements, stresses and anenhanced strainfield is presented which encompasses, as a particular case, the classical method of incompatible modes. Within this frame‐work, incompatible elements arise as particular ‘compatible’ mixed approximations of the enhanced strain field. The conditions that the stress interpolation contain piece‐wise constant functions and beL2‐ortho‐gonal to the enhanced strain interpolation, ensure satisfaction of the patch test and allow the elimination of the stress field from the formulation. The preceding conditions are formulated in a form particularly convenient for element design. As an illustration of the methodology three new elements are developed and shown to exhibit good performance: a plane 3D elastic/plastic QUAD, an axisymmetric element and a thick plate bending QUAD. The formulation described herein is suitable for non‐linear analysis.