Combining interface damage and friction in cohesive interface models using an energy based approach

Abstract

Cohesive zone models coupling interface damage and friction have been developed in the literature and are available in the commercial finite element package ABAQUS to consider the enhancing effect of through-thickness compression on interfacial fracture resistance. It is revealed in this paper that these models are extremely dependent on interface stiffness, because interface stiffness reduction factor is used to combine damage and friction in these models. The interfacial constitutive law converges but only when the interface is extremely stiff and an unrealistic evolution of the interface damage is produced. A new approach is then developed which uses a cohesive energy related parameter to combine interface damage and friction. The behaviour of the new coupled model is independent of the interface stiffness once the interface is moderately stiff. The new and existing damage/friction coupled models have been employed to simulate the shear failure of a composite specimen and the predictions are compared against the experimental data in the literature. The new model produces converged results over a wide range of interface stiffness and the predictions match the experiments quite well, better than the existing models.

Effect of friction and shear strength enhancement on delamination prediction

“…The cohesive model was developed to take into account the enhancing effect of through-thickness compression on Mode II (in-plane shear) fracture. The enhancement of interfacial shear strength in the damage model is defined as; 19 where τ2cn is an enhanced shear strength and η is an enhancement factor to take account of the through-thickness compression. τ2c is the interface shear strength of Mode II.…”

Progressive failure mechanism of laminated composites under fatigue loading

“…25 This criterion has been successfully utilized by many researchers e.g. Hameed et al., 26 Zou and Hameed, 27 Belnoue et al. 17 and Kawashita and Hallett, 12 and is written as; where τn,normal τs,normal τt are the normal, shear and tear stresses respectively and where the operator 〉〈|xnormal is defined as; …”

“…25 This criterion has been successfully utilized by many researchers e.g. Hameed et al, 26 Zou and Hameed, 27 Belnoue et al 17 and Kawashita and Hallett, 12 and is written as;…”

A new approach to the cohesive zone model that includes thermal effects

“…The materials properties of interfacing element, used in simulation, are listed in Table 2. According to (Zou and Hameed 2018), an interface stiffness of 1x10 14 N/m 3 was adopted in the finite element model. The element type adopted for the layers was the 4-node bilinear, CPS4, and for the adhesive layer the 4-node cohesive element COH2D4 was used.…”