奇应变拟协调元

由于奇应变元与常规元在接触面上的位移往往是不协调的,因而用这两种单元结合的有限元法来确定应力强度因子的情况下,就不能按虚功原理进行计算.为此,本文引进了拟协调条件,构造出一个奇应变拟协调元,并计算出它的刚度矩阵.两刚算例所得的结果与其他方法得到的基本相同.通过计算还可发现:奇应变拟协调元的尺寸也此通常的奇应变元要大得多,从而就可以避免使用过渡单元.此外,本文还对常用的几种奇应变元的协调性进行了讨论.

Singular Strain Quasi Conforming Elements

In determining the stress intensity factors with the combined singular strain elements and ordinary elements,the principle of virtual work cannot be used, because of the unconformity of the displacements on the interfaces between the two kinds of elements. For this reason, this paper introd- uces the quasi-conforminy condition. A singular strain quasi-conforming element is constructed and its stiffness matrix is worked out. Two examples of calculaton with this method are given. The comparison between the results obtained using this method with those obtained usiny other methods shows that they are basically the same, The size of the singular strain quasi-conforming element is much larger than that of the ordinary sinyular strain element, hence the use of the transition element can be avoided. Futhermore, this paper also discusses the conformity of some ordinary singular strain elements.