Cohesive zone modeling of thin aluminium sheets

Abstract

Single edge notch(SEN) aluminium specimens of widths (D): 20, 40 and 50mm are tested under uniaxial tensile loading for a strain rate of 0.005/minute. The notch depth to width ratio (a/D=0.25) and the gauge length to width ratio (L/D=2.5) are constant for these tested specimens. The load versus deflection curves are analyzed using cohesive crack model. The peak stress data are analyzed using equivalent elastic crack model. The fracture energy Gf obtained from these approaches are compared. Uniaxial tensile testing of 50mm width SEN specimens(L/D=2.5) with ligament lengths of 2.5, 5, 7.5, 10, 12.5 and 15mm is carried out. A linear regression fit between work of fracture per unit ligament area and ligament length is used to determine the essential work of fracture. An energy based approach involving fixed point iteration method to calculate the crack length at peak load is proposed.