一种含Allman型转角自由度的杂交元

A Kind of Hybrid Element Including Allman Type Drilling Degrees Of Freedom

基于组合杂交变分原理,使用单元内部位移提高含转角自由度的插值阶次,并由此优化线性应力,得到CHDB单元.它既满足杂交方法所要求的inf-sup条件,又有较高的位移、应力精度;和普通的八节点二次单元相比计算花费少;对单元几何形状不敏感;能很好地模拟弯曲变形;克服Poisson Locking.

A new element （ CHDB ） is proposed in this paper based on combined hybrid variational principle. Inner displacements are used to improve the interpolation order of displacements include drilling degrees of freedom and optimize the linear stress. The new dement not only satisfies inf-sup condition but also achieves high accuracy of both displacements and stresses. Compared with 8-node quadrilateral element, the computational cost of CHDB is lower. Moreover, it is insensitive to mesh distortion as well as simulating bending problems accurately, conquer Poisson Locking.