Fatigue behavior and modeling of chopped carbon fiber reinforced sheet molding compound composites

Abstract The quasi‐static and fatigue behavior of chopped carbon fiber reinforced sheet molding compound (SMC) composite was investigated. The microstructure of material was inspected by X‐ray Computerized Tomography (XCT) and the fiber orientation distribution was analyzed. Quasi‐static tensile test was performed on specimens with different gauge length to study the size effect on mechanical properties and digital image correlation system was applied to record the strain distribution. The fatigue behavior of material was evaluated under both tension‐tension (R = 0.1) and tension‐compression (R = −1) loadings, in which XCT scanned specimens were tested to characterize the microstructure at failure location. Interrupted fatigue test was performed to observe the damage evolution process on the side surface of specimen by optical microscope and the dominant fatigue failure modes were identified. A representative volume element based modeling methodology was modified and applied to establish the relationship between heterogenous microstructure and macroscopic mechanical behaviors. The simulation results show good consistency with experimental observations which demonstrates the effect of local fiber orientation on durability performance of material.