An economical assumed stress brick element and its implementation

Abstract

In this paper, a highly economical 8-node brick element consolidated from the previous work on admissible matrix formulation and selective scaling is discussed. The element is modified from the Pian-Tong element in a way that the latter's good bending response, applicability in nearly incompressible materials and insusceptibility to mesh distortion are retained. Moreover, the selective scaling technique is incorporated such that the element can also be used thin plate/shell analysis. Focus is on systematic and economical construction of the element stiffness matrix. Using the present implementation which employs numerical integration, it is found that the element is less costly than the 8-node displacement element. CPU time comparisons, benchmark problems and FORTRAN-subroutines are presented.