Crack growth analysis and residual life estimation of structural elements under mixed modes

Attention in this work is focused to crack growth analysis and residual life estimation of metal structural components under mixed modes I/II. Primary attention of this investigation is numerical simuation crack growth trajectory. For this purpose FEM is used together with the maximum tangential stress (MTS) criterion. To determine crack growth trajectoties of cracked structural components under mixed modes convencional singular finite elements are used. In this investigation specimen with two holes and crack between its is considered. The crack between two holes is defined to achieve mixed mode I/II crack growth trajectory.The main objective of this work is to develop a computational analysis methodology to simulate realistic crack growth and to predict remaining life and residual strength of complex aircraft and another flight structures. Modern aircraft structures are designed using damage tolerance philosophy. This design philosophy envisions sufficient strength and structural integrity of the aircraft to sustain major damage and to avoid catastrophic failure. An special attention in this work is focused to study the effects of initial angle of crack between two holes on crack growth trajectories. Computation crack growth trajectories are compared with own experimental results. There are good agreements in determining the path of the crack growth and life estimation. Good agreement between computation and experimental crack growth trajectory is obtained