A Damage Tolerance Model for Plates with Surface Cracks Under Combined End Force and Bending

ABSTRACT

Reference stress statuses and the critical crack sizes are analyzed systematically and in detail for rectangle surface cracks in plates under combined endforce and cross-thickness bending loads via the ‘global’ reference stress method. The relationships of critical crack width and depth are obtained from the critical crack sizes analysis. Based on the net-section plastic collapse of the flawed component, a damage tolerance mathematical model for plates with single crack was built, which did not consider the contact of crack faces and it can be used for plates with a shallow crack or a deep crack under combined endforce and cross-thickness bending load. Using this mathematical model, the damage limits of aluminum alloy plates under different bending loads are obtained and a simplified damage tolerance model for aluminum alloy plates is established via regression analysis. The results obtained from the model and the regression model agree well with the experimental results especially when a/t<0.8. The test results show that the model can be fast and conveniently predict the damage limits for plates with surface cracks under bending.

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