Fatigue crack growth under variable-amplitude loading: Part II – Code development and model validation

Fatigue Crack Growth Simulation of Aluminium Alloy under Cyclic Sequence Effects

“…The changes of a stress ratio related to changing of minimum stress with a constant maximum stress. The data predicted using the Austen, modified Forman and NASGRO models are compared with those models performed by previous literatures [Ray & Patanker, 2001b;Huang, et al, 2005a;Huang, et al, 2005b]. The maximum differences in life predicting for the load cases for all models are 40% as a maximum compared to the test data.…”

“…Thus, the fatigue crack propagation models under VA loading are presented in this section based on the Austen, modified Forman and NASGRO models. For demonstrating the validation of these models predictions are compared with test data, FASTRN and AFGROW codes given in Ray and Patanker [2001b].…”

“…the effect of a load cycle on crack growth in later cycles. The programmable and VA load histories given by Ray and Patanker [2001b] and Huang et al[2005b] are used in this analysis with different load sequences from high to low or low to high shown in Fig. 4 (load cases 1 to 5).…”

“…However, the Willenborg model was found to be not reliable for predicting the overload retardation [Taheri, et al, 2003]. The second main category of retardation models, known as the crack closure models, is based on Elber's experimental observation [Elber, 1971], which used to model crack growth rates under VA loadings [Schijve, 1981;Newman, 1984;Ray & Patanker, 2001a;Ray & Patanker, 2001b]. As a result of the tensile plastic deformation left in the wake of a fatigue crack, a partial closure of the crack faces occurs during part of a fatigue load cycle.…”

Fatigue Life Prediction Using Hybrid Prognosis for Structural Health Monitoring

“…In contrast, the crack growth caused by variable amplitude loading is characterized by acceleration and retardation effects [1][2][3], which significantly affect the RUL. Currently there are many physics based models [1][2][3][4][5][6] to model crack growth with acceleration and retardation effects. These models capture the fatigue crack growth phenomena reasonably well under variable loading, but in a deterministic framework.…”