Progressive matrix cracking induced delamination: A comparison of finite element modelling techniques

One of the major failure modes in composite laminates is interlaminar delamination which can initiate from stress concentration at transverse matrix crack tips. This failure interaction is referred to as Matrix Cracking Induced Delamination (MCID). MCID in [90/0/90] HTA/6376 carbon fibre reinforced cross-ply laminates subjected to four-point bending is numerically investigated. Failure interaction is quantitatively studied in a Finite Element (FE) framework by means of two different modelling techniques in the standard FE analysis software Abaqus. One modelling technique includes user-defined Advanced Phantom Node Method (APNM) elements which allow for arbitrary fracture modelling while preserving elemental locality. Another model exclusively uses built-in functions and pre-inserted matrix cracks in Abaqus. Numerical results are compared to experimentally obtained fracture measures. Both models are able to predict the overall load response, matrix crack density and progressive MCID growth in the interface with reasonable accuracy. However, APNM does not require a priori knowledge about location of matrix cracks and a number of assumptions and simplifications in the advanced model reduces runtime analysis by up to 50%. It is concluded that APNM is a promising effective numerical tool which is applicable to standard FE software packages