构造含结点旋转单元的坐标变换法

Coordinate Tranformation to Construct Element with Vertex Rotations

Allman提出了带角结点旋转的三角形单元及相应的四边形单元，法向位移的二次插植保证了该单元的精度，但带来了构成单元的复杂．本文把Allman单元看成对一个有边中结点单元进行坐标变换的结果，大大提高了计算效率．

Allman has introdced triangular and quadrilateral element including vertex rotations.Tests show the elements to be of acceptable accuracy but complex constructing. In Presentpaper the Allman element is regarded as a result of applying a coordinate transformation toan element that has midside nodes. This method is simple and efficient.