Investigation of analytical model of crack propagation under multi axial fatigue in fiber metal laminate

Abstract

Mostly the aerospace and other applications parts during their service life are subjected to the multi axial fatigue with non-proportional loading. In this study, the fatigue crack growth in glass laminate aluminum reinforced epoxy subjected to special case of non-proportional multiaxial fatigue (cyclic tension with constant shear) has been investigated. New prediction analytical model used empirical Paris equation has been adopted. Crack-growth rate was in relation with the equivalent stress-intensity factor for mixed mode at the crack-tip. Bridging stress-intensity factor was superimposed with the far-field stress-intensity factors to evaluate the equivalent stress-intensity factor. Bridging stress distribution, crack opening contour, delamination shape and its growth have been estimated simultaneously to evaluate the bridging stress-intensity factor. The obtained results indicated that there was a considerable enhancement in the crack growth rate (193.8%), number of cycles required to full failure (192%) and other performance characteristic as compared with the monolithic aluminum. Numerical simulation by ABAQUS 2021 software has been implemented to verification of the analytical model. A significant convergence in behavior between the extracted results from both analytical model and numerical simulation with maximum deviation reach to 8.2%.

Keywords

• Multi axial fatigue, Crack growth rate
• GLARE
• Delamination growth
• Bridging stress
• Equivalent stress intensity factor