Experimental and numerical investigation on compression after impact behavior of hygrothermal aged CFRP laminates

In the paper, a detailed experimental and numerical investigation of compression after impact (CAI) behavior of hygrothermal aged T300 985LV carbon/epoxy composites is presented. Rectangular fabric laminates are damaged by low‐velocity impact, and moisture absorption conditioning is carried out. The moisture absorption curves agree with Fick's law, with a moisture equilibrium rate of 0.84% at 1392 h. Then, CAI experiments are carried out on moisture saturated specimens at different temperatures. The effects of hygrothermal environments on CAI strength are obtained with an interpretation of corresponding mechanism. Furthermore, finite element analysis based on hygrothermal mechanics formulation and incremental Newton–Raphson mixed iteration equation is established. The numerical results are in good agreement with the experimental ones, with an accuracy of up to 92%, which demonstrates the effectiveness of the established numerical model. The results show that the CAI strength of 85 RH% hygroscopic saturated laminates is decreased by approximately 12% at 85°C and 17% at 128°C. Additionally, the allowable compression value of 3546 μɛ is obtained for T300 985LV composite laminates, which is useful for applications in civil aircraft design. This work investigates the effect of hygrothermal environments on the compression after impact (CAI) of CFRP laminates. The results show that the CAI strength of 85RH% hygroscopic saturated laminates is decreased by approximately 12% at 85°C and 17% at 128°C. The proposed research is of utmost importance for industrial applications since it provides the residual strength of the laminates as a function of environmental variability, which is an essential datum for design choice.