Quasistatic crack propagation in nonlinear structures

Abstract

'Quasistatic' is used in the sense that negligible generation of kinetic energy occurs during cracking. ‘Nonlinear’ is used to describe structural behaviour for which reversible deformation at constant crack area is not proportional to force. Common examples are structures in which membrane stresses at greater loads reinforce initial bending resistance; and the inverse effect (buckling) when bending resistance at larger deflexions reinforces initial membrane action. Throughout the paper irreversible deformation is limited to a boundary layer along the crack surface. Within this limitation, a general theory of quasistatic crack propagation is developed, and applied to the cracking of strips, plates and cylindrical shells. Experiments to support and illustrate the theory are described.