A FAILURE CRITERION FOR BIMATERIALS WITH CRACKS AT THE INTERFACE OF DISSIMILAR MATERIALS
D.A. Kuznetsov, V.D. Kurguzov
Lavrentyev Institute of Hydrodynamics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: bimaterial, interface crack, crack path kinking, mixed-type loading, failure criterion
Abstract
The propagation of a rectilinear crack at the interface of dissimilar materials is investigated. A two-parameter (dual) elastic-plastic failure criterion for mixed-type cracks is proposed. This criterion includes a deformation criterion formulated at the tip of the initial crack and a force criterion formulated at the tip of a fictitious crack. The lengths of the initial and fictitious cracks differ by an amount equal to the length of the process zone. Because the crack path at the interface between materials is curved, the fracture angle is determined using the maximum tangential stress criterion based on the asymptotic expansion of the stress field in the vicinity of the crack tip, taking into account non-singular terms. A modified Leonov-Panasyuk-Dugdale model of the end zone of a sharp internal crack is used to describe the process zone. The parameters entering the resulting analytical model are analyzed. The dimensionless geometric parameters of the structure are determined numerically using the finite element method. A system of two nonlinear equations is obtained for the critical length of the process zone and the critical load under mixed-type (complex) stress state conditions. The shape and dimensions of the process zone in the vicinity of the crack tip in a nonlinear elastic material are determined using the von Mises criterion.
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