EXPLANATION AND ELIMINATION OF SHEAR LOCKING AND MEMBRANE LOCKING WITH FIELD CONSISTENCE APPROACH

In this paper, in the context of beam elements, shear locking and memb rane locking are explained and cured in a unified way with a field con sistence approach. In the view of field consistence approach, when tra nsverse displacements are coupled with section rotations in Euler-Lagr angian equations and low order interpolations are adopted,shear lockin g will occur. Similarly, when in-plane displacements are coupled with section rotations in Euler-Lagrangian equations and low order interpol ations are used, membrane locking will happen. The beam elements deriv ed by field consistence approach are not only free of shear lacking an d membrane locking but also highly efficient, compared with their isop arametric counterparts. Although theoretically the internal forces/gen eralized strains in mixed variational principles can vary independentl y, they are neither independent to each other nor independent of displ acement fields from the point of view of the field consistence approac h. (C) 1998 Elsevier Science S.A. All rights reserved.