Inverse first-order reliability method for probabilistic fatigue life prediction of composite laminates under multiaxial loading

Inverse first-order reliability method for probabilistic fatigue life prediction of composite laminates under multiaxial loading Yibing Xiang and Yongming Liu* Department of Civil and Environmental Engineering Clarkson University Potsdam NY.13699, USA Abstract: Multiaxial fatigue reliability is a challenging problem despite extensive progress made during the past few decades. Anisotropic materials, such as composite laminates, are under general multiaxial stress state even if the applied loading is uniaxial. A general methodology for multiaxial fatigue reliability analysis of composite laminates is proposed in this paper. The proposed methodology is based on a unified multiaxial fatigue model for both isotropic and anisotropic materials and the inverse first-order reliability method (Inverse FORM) for probabilistic life prediction. The current fatigue model is a critical plane-based model. The critical plane orientation is theoretically determined by minimizing the damage introduced by the hydrostatic stress amplitude. One of the advantages of the multiaxial fatigue model is that it has almost no applicability limitations with respect to different materials. A time dependent limit state function of material failure is developed based on the proposed mechanism model for probabilistic life prediction. Inverse FORM method is proposed to calculate the fatigue life under a specified failure probability. Various uncertainties from materials properties, ply configurations, and volume fractions are included in the proposed methodology. A wide range experimental fatigue data of composite laminates is used to validate the proposed methodology. It is observed that the proposed methodology gives a satisfactory