Damage modelling in woven-fabric CFRP laminates under large-deflection bending

In this paper, various damage modes in woven carbon fabric reinforced polymer (CFRP) laminates are studied using experimental material characterisation and numerical simulations. Experimental tests are carried out to assess the mechanical behaviour of these materials under tension, compression and large-deflection bending. To obtain in-plane shear properties of laminates, tensile tests are performed using a full-field strain-measurement digital image correlation technique. Two-dimensional finite-element models are implemented in the commercial code Abaqus to study the deformation behaviour and damage in large-deflection bending of CFRP laminates. In these models, multiple layers of bilinear cohesive-zone elements are employed between elements of each fabric ply to analyse the onset and progression of inter-ply delamination. Intra-ply fabric fracture is modelled by inserting a transverse layer of cohesive elements at the laminate centre. The developed numerical models are capable to simulate these damage features as well as their subsequent mode coupling observed in tests. The obtained results of simulations show good agreement with experimental data, thus demonstrating that the proposed methodology can be used for simulations of discrete damage mechanisms and their interaction during the ultimate fracture of composites in bending.