Rapid Analysis Method for Composite Compression after Impact Strength Prediction

摘要

Fiber-reinforced composite structures are often subjected to accidental impact loads that may result in significant surface and sub-surface damage. In the case of low-velocity (and low-energy) impact, the surface damage may be small but the sub-surface damage - in the form of delaminations, matrix cracking, and fiber breakage - can be significant. Irrespective of the type of impact damage, it is essential to determine the post-impact residual properties of the material so that appropriate safety margins can be incorporated into the structural design. One of the key properties of interest is the Compression after Impact (CAI) strength as compressive strength is typically lower than tensile strength and the detrimental effect of impact on its magnitude is more severe. CAI strength is often measured experimentally by subjecting the laminates of interest to an expected level of impact energy or damage followed by a compression test. However, this approach is time-consuming and expensive and in turn limits the design space. In order to improve the efficiency of composite laminate design based on CAI strength, a rapid analysis framework is developed. Because this analysis tool utilizes analytical or simple numerical solutions for the prediction of CAI strength, its computational efficiency permits its use in the early design process. The developed tool is called upon to predict the CAI strength for various scenarios including different material systems, layups, and impact damage type, size, and morphology. Predictions are shown to be sufficiently accurate for use in preliminary design and enhancements to the model are presented that improve its generality.