Failure mechanisms based degradation model of unidirectional fiber reinforced polymer composites

Based on the failure mechanisms and mechanics of composite, a new degradation model for unidirectional fiber reinforced polymer composites was established to describe the degradation behavior of different failure modes. The difference between the tensile and compressive modulus, the different degradation of damage on the tensile and compressive modulus, the crack closure and the influence of the lateral supports were considered in the proposed model. The proposed model is convenient to use because only fundamental material properties are required. The degradation model for T800/X850 carbon fiber/epoxy composite was established and the progressive failure analyses of typical bolted composite joints were performed. The numerical predictions of failure load, failure patterns, and load-displacement curve were compared with results obtained from static tests. Good agreements between numerical failure predictions and experimental outcomes indicate the effectiveness and suitability of the proposed model.