Interaction of Matrix Cracking and Delamination in Cross-ply Laminates: Simulations with Stochastic Cohesive Zone Elements

Abstract

Two main damage mechanisms of laminates-matrix cracking and inter-ply delaminationare closely linked together (Joshi and Sun 1). This paper is focussed on interaction between matrix cracking and delamination failure mechanisms in CFRP crossply laminates under quasi-static tensile loading. In the first part of the work, a transverse crack is introduced in 90o layers of the cross-ply laminate [01/904/01], and the stresses and strains that arise due to tensile loading are analyzed. In the second part, the cohesive zone modelling approach where the constitutive behaviour of the cohesive elements is governed by traction-displacement relationship is employed to deal with the problem of delamination initiation from the matrix crack introduced in the 90o layers of the laminate specimen. Additionally, the effect of microstructural randomness, exhibited by CFRP laminates on the damage behaviour of these laminates is also accounted for in simulations. This effect is studied in numerical finite-element simulations by introducing stochastic cohesive zone elements. The proposed damage modelling effectively simulated the interaction between the matrix crack and delamination and the variations in the stresses, damage and crack lengths of the laminate specimen due to the microstructural randomness.

Numerical modelling of the damage modes in UD thin carbon/glass hybrid laminates

“…Therefore, this approach is suitable for investigating the stress concentration in the glass layer around the fragmented carbon layer. There are certain similarities with [15] in which the interaction of matrix cracking and delamination has been studied in cross-ply laminates. The transverse crack was assumed open and the delamination propagation modelled using cohesive elements.…”

The significance of nanoparticles on bond strength of polymer concrete to steel

“…Bilinear shear stress-slippage relationship was used to describe the contact element as shown in Fig.4(b) [29,30]. This relationship is based on pure in-plane shear fracture mode (mode II) and is defined in ABAQUS using damage and cohesive behavior interaction [31].…”

Micromechanical analysis of stochastic fiber/matrix interface strength effect on transverse tensile property of fiber reinforced composites

“…When investigating the stochastic fracture toughness effect on the delamination process of a DCB specimen, Ashcroft et al assumed the initial stiffness and fracture toughness to be proportional to the interface strength. [14][15][16][17] Similar approach was adopted in the present work (Figure 5), and the critical and failure separation of the cohesive interface were taken as 0 ¼ 10 À9 m and f ¼ 2 Â 10 À7 m (the two values were chosen by consulting parameter dimension in the literatures 7,9,10 ), respectively. To promote the solution convergence, a viscosity coefficient of 2 Â 10 À4 taken from O'Dwyer et al 7 was used.…”

“…Failure process of materials with stochastic local property is significantly different from that of identical cases. Ashcroft et al [14][15][16][17] investigated the random fracture toughness effect on the delamination process of a double cantilever beam (DCB) specimen with stochastic cohesive element and concluded that the microstructural randomness could significantly affect the macroscopic delamination process of composites.…”