引入旋转自由度的杂交混合单元

文中指出了一个杂交混合型含角点旋转的四边形单元。相容部分位移场以八结点Ｓｅｒｅｎｄｉｐｉｔｙ单元经一个坐标变换导出，不相容部分位移场和相应的内应力场被详尽讨论。特征值检验和路径实验说明新单元的有效，精选解例证明了新单元的杰出性能。

Quadrilateral Element with Drilling Rotation: Hybrid Mixed Formulation

In the present investigation, a guadrilateral element with drilling rotations is proposed based on hybrid mixed formulation. The compatible component of the interior displacement field can be derived from the eight node Serendipity element by employing a linear transformation. The incompatible displacement and stress field is defined as functions of a set of undetermined parameters. The eigenvalue test and patch test are passed, numerical results show that the element yield excellent accuracy.