An 8-node low-order Hexahedral Incompatible Element Insensitive to Mesh Distortion

Although many 3D 8-node hexahedral elements have appeared, the sensitivity problem to mesh distortion for 3D elements is still a problem to be solved, especially for low-order element models. In this paper, a low-order hexahedral incompatible element OCH8 is successfully established with the principle of minimum potential energy. In order to avoid the loss of element accuracy caused by coordinate transformation, the basic displacement field and internal parameter displacement field are both expressed by the 3D local oblique coordinate. Compared with traditional 8-node hexahedral elements, the performance of this element does not depend on the shape of meshes, and it can still keep high precision for various severely distorted meshes even when four nodes on the element plane are not coplanar.