Elastic modulus reduction method for limit analysis of thin plate and shell structures

The paper proposes an efficient numerical method, namely, the elastic modulus reduction method (EMRM) to calculate lower-bound limit loads of thin plate and shell structures. To determine the elastic modulus adjustment parameter q in a rational way, the precisions and convergent properties of four different strategies of elastic modulus adjustment (SEMAs) combined with the EMRM are investigated. Furthermore, to take into consideration the plastic resistances as well as the internal forces in the processes of elastic modulus adjustment, the element bearing ratio (EBR) of thin plate/shell element is defined as the governing parameter based on the generalised yield criterions. The flexibility and accuracy of the proposed EMRM combined with both the strain energy equilibrium principle (SEEP) and the fixed strain method (FSM) are demonstrated in the numerical example. (C) 2009 Elsevier Ltd. All rights reserved.