Prediction of delamination crack growth in carbon/fiber epoxy composite laminates using non-local interface damage model

Abstract

The use of composite laminates is increasing in these days due to desired directional properties and low densities in comparison of metals. Delamination is a major source of failure in composite laminates where a crack like entity can initiate and propagate between different layers of composite laminates under given loading conditions. Damage mechanics based theories are employed to simulate the delamination phenomena between composite laminates. These damage models are inherently local and can cause the concentration of stresses around the crack tip. In the present study integral type non-local damage formulation is proposed to avoid the localization problem associated to damage formulation. A comprehensive study is carried out for the selection of different non-local variables. Finite element simulations based on proposed non-local damage models and classical local damage model are performed and results are compared with available experimental data for UD IMS/924 Carbon/fiber epoxy composite laminate.

Mathematical modelling and simulation of delamination crack growth in glass fiber reinforced plastic (GFRP) composite laminates

“…The classical interface damage model shows the strain softening phenomenon during the degradation process (Borino et al, 2007;Ijaz et al, 2014). Due to this softening behaviour, the stress tends to localize in a narrow region in front of the crack tip.…”

“…This domain dependent characteristic length l will also simulate the fibre bridging behaviour since bridging occurs over a certain domain during delamination crack growth in composite laminates. Now one can write the average of damage variable d over the surrounding domain using the weight function α 0 (r) (Ijaz et al, 2014)…”

“…Borino gave the idea of using the integral type non-local damage model for the interface damage models for composite laminates (Borino et al, 2007). Ijaz used the idea of an integral type non--local interface damage model for the study of delamination crack growth in CFRP composite laminates (Ijaz et al, 2014). GFRP composite laminates also show a considerable amount of fiber bridging during crack growth (Davidson and Waas, 2012).…”

Non-coherent energetic interfaces accounting for degradation

“…[1,3,5,10,16,18,19,53,57,77] employed the continuum damage mechanics approach to model the degradation of non-coherent, cohesive interface elements. A formulation for a non-local damage-type cohesive zone model was provided by [14,42]. Within a thermomechanical framework [32,35,69,91]…”

“…and using the extended forms of divergence theorem (42) and (43), for various parts of the body results in…”