Non-linear material characterization of CFRP with FEM utilizing cohesive surface considerations validated with effective tensile test fixturing

Abstract

Modelling the effect of fibre orientation in carbon fibre reinforced plastic (CFRP) on mechanical behaviour is critical for component design and manufacturing process optimization. The objectives of this paper are to simulate the mechanical properties of CFRP to fracture and design a tensile test rig that could induce fracture at the specimen gauge section consistently. Finite element solver ABAQUS Explicit was used to simulate the effects of mass/time scaling, different failure models and cohesive surfaces. Failure models evaluated were Hashin, MCT, LaRC02, maximum strain, Tsai-Wu, Tsai-Hill, Christensen and Puck. The fibre orientations investigated were parallel, 45° and perpendicular to the tensile loading condition. Extensive design of the tensile test rig was briefly described. Experimental results showed that with the newly designed test rig, the failure occurred in the gauge region, regardless of the fibre orientation. When the fibre orientation was parallel to the tensile load, all the failure models show similar rate of force increment with respect to displacement. Puck's failure model most accurately predicts the fracture force and displacement versus experimental data. With fibre orientations at 45° and 90°, the maximum strain and LaRCO2 failure models were more suitable in terms of accuracy and simulation convergence. Incorporating cohesive surfaces between instances to predict nonlinearity in the loading response is critical. Significant reduction in failure force was predicted when test was setup at angles between parallel to 45°. The model was capable of predicting the effects of fibre orientation and laminate thickness on fracture force agreeing with published experimental results.