Probabilistic approach for residual compressive strength of CFRP laminates, following low velocity impact

The impact sensitivity of FRP laminates constitutes a major concern to designers, as it may result in substantial reduction of both tensile and compressive strength, without warning. In particular, for CFRP laminates used primarily in the aerospace industry, reliable predictive tools are required to allow optimized damage tolerant designs. This work presents an elaboration of a model earlier developed by one of the authors which has proven to have extended applicability to CFRPs. Probabilistic definitions of the prepreg material properties, on which model predictions are strongly dependent are embedded in the definition of the bending mismatching coefficient, a fundamental dimensionless quantity of the model. The predictions yielded by the model are based on a previously experimentally obtained nomograph, accounting for the influence of 0°, ±45° and 90° prepreg plies volume contents on the laminate impact energy absorption capacity. Deterministic and probabilistic predictions are compared against experimental residual compressive strength results for UD, angle ply, quasi-isotropic and cross-ply laminates made of the BASF Rigidite 5212 material system. The quality of both prediction types and practical aspects of the probabilistic approach are discussed.