Fatigue Life Prediction for SiC/Al Materials Based on Path Planning Algorithm Considering Residual Stress

Abstract

To explore the influence of path deflection on crack propagation, a path planning algorithm is presented to calculate the crack growth length. The fatigue crack growth life of metal matrix composites (MMCs) is estimated based on an improved Paris formula. Considering the different expansion coefficient of different materials, the unequal shrinkage will lead to residual stress when the composite is molded and cooled. The crack growth model is improved by the modified stress ratio based on residual stress. The Dijkstra algorithm is introduced to avoid the cracks passing through the strengthening base and the characteristics of crack steps. This model can be extended to predict crack growth length for other similarly-structured composite materials. The shortest path of crack growth is simulated by using path planning algorithm, and the fatigue life of composites is calculated based on the shortest path and improved model. And the residual stress caused by temperature change is considered to improve the fatigue crack growth model in the material. The improved model can well predict the fatigue life curve of composites. By analyzing the fatigue life of composites, it is found that there is a certain regularity based on metal materials, and the new fatigue prediction model can also reflect this regularity.