Fatigue crack growth in Ti-6242 under elasto-plastic loading conditions

The applicability of LEFM is investigated in this paper. Experiments with loads corresponding to load controlled LEFM conditions and LCF strain controlled conditions were carried out and the crack propagation was monitored. The experiments were evaluated according to standard procedures for crack propagation testing, ASTM E 647. The results from the LCF experiments were evaluated using linear elastic representation of the load in the crack vicinity i.e. KI. The results show that although essentially elastic stress response is observed the use of LEFM and material data obtained under LEFM loading situations resulted in non conservative crack propagation rate predictions for LCF loads. However, the LEFM methodology could be used to accurately describe the fatigue crack growth behavior using material data from the LCF tests but further work is needed for such methodology to be implemented in a life calculation system.