Elastic-plastic analysis of biaxially loaded center-cracked plates

Center-cracked panels loaded in biaxial tension are examined in this paper. Calibration relations for the J integral and the Q constraint factor are presented fora Ramberg-Osgood power law hardening material under plane stress and plane strain loadings. Two cases are examined:an isolated crack and a periodic array of cracks both under biaxial loading conditions. The latter has previously been studied: for plane stress conditions. A number of different J estimation schemes are proposed based on the remote load and displacement and their dependence on geometry, biaxiality, and material properties is discussed. The variation of constraint, as characterised by Q, is also presented for plane stress and plane strain conditions. Simple slip line field solutions are derived for perfectly plastic conditions and the resulting limit load solutions are compared with numerically determined values. Implications for failure of cracked plates under biaxial loading are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.