无锁定的退化的等参壳元

Locking-Free Degenerated Isoparametric Shell Element

构造了一个无锁定的 8节点退化的等参壳元· 在自然坐标系中 ,对横向剪应变项插值修正使单元满足必要的模式 (平移、转动和纯弯曲 )以消除“剪切锁定” ;在局部坐标系中 ,对薄膜应变插值修正以消除“薄膜锁定”· 这样构造的 8节点单元的刚度矩阵具有正确的秩 ,同时具有恰当的零特征值和相应的刚体位移模式· 这种单元对大跨_厚比情形既无“剪切锁定”又无“薄膜锁定” ,无虚假的零能模式和机构出现 。

An 8_noded locking_free degenerated isoparametric shell element is presented. A revised interpolation for shear strain terms was constructed in natural co_ordinate system such that all necessary modes (translation, rotation and constant curvature) are preserved, which can be used to eliminate shear locking. A revised interpolation for membrane strains was produced in the local Cartesian co_ordinate system to overcome membrane locking behavior. The new 8_noded element has the proper rank, with the requisite number of zero eigenvalues each associated with a rigid mode. The element does not exhibit membrane or shear locking for large span_thickness ratio. The element does not form element mechanisms or extra spurious zero energy modes. Therefore, it can be used for both thin and thick shells.