Dynamic Effects on Fatigue Crack Growth

Abstract

The influence of dynamic (inertial) effects on fatigue crack growth is studied in this paper. The crack growth zone is modeled by cohesive interfaces whose separation process is described by a fatigue cohesive zone model. Two different loading types are considered: one in which the loading increases to a maximum value in a certain time interval and the other one where loading is cyclic. Quasi-static and dynamic solutions are compared to establish the conditions in which the dynamic effects become important in the analysis. It is discussed how loading speed and frequency can modify crack growth characteristics such as, growth rate, crack extension and time for the beginning of the growth process. It is observed that loading speed and frequency may even change the failure mode of cracked structures from crack propagation to uniform debonding. Stress distribution and crack evolution through time are also investigated.