A HYBRID/MIXED MODEL FINITE ELEMENT ANALYSIS FOR EIGENVALUE PROBLEM OF MODERATELY THICK PLATES

The buckling and free vibration problems of moderately thick plate are considered inthis paper by using the hybrid/mixed finite element model.A modified Reissner principlewhich only requires C~0 continuity is derived.No lockling phenomenon is observed.Linearinterpolation is used for all independent unknown function.Finally a displacementgeneralized eigenvalue equation is obtained,in which the stiffness matrix is symmetric andpositively definite.The calculated results show that the method proposed is simple,reliableand satisfactory.     

中厚板特征值问题的杂交/混合有限元分析

本文采用杂交/混合有限元对中厚板的屈曲问题和自由振动问题进行了分析,首先推导了一个修正的Reissner变分原理,它仅要求构造C0类场变量,避免了闭锁现象的产生。所有的场变量皆采用线性插值。最后得到一个矩阵型的位移广义本征值方程,刚度矩阵对称、正定。计算结果表明本文采用的方法简单、可靠,较为令人满意。     

A hybrid/mixed model finite element analysis for eigenvalue problem of moderately thick plates

The buckling and free vibration problems of moderately thick plate are considered in this paper by using the hybrid/mixed finite element model. A modified Reissner principle which only requires C⁰ continuity is derived. No lockling phenomenon is observed. Linear interpolation is used for all independent unknown function. Finally a displacement generalized eigenvalue equation is obtained, in which the stiffness matrix is symmetric and positively definite. The calculated results show that the method proposed is simple, reliable and satisfactory.