On cohesive element parameters and delamination modelling

Lü, Xin; Ridha, M.; Chen, B. Y.; Tan, V.B.C.; Tay, T.E.

doi:10.1016/j.engfracmech.2018.12.009

Cited by 107 publications

(33 citation statements)

References 89 publications

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“…Total 395,032 full integrated Lagrangian solid elements discretized the GLARE laminate. Keeping the interfacial strength, the finer CZEs fail faster [45]. The tendency is opposite when the CZEs are coarser [45].…”

Section: Discretizationmentioning

confidence: 97%

“…Though, cross-ply GF/EP laminates were incorporated in the stacking sequence, the insertion of isotropic Al-layers resulted in a quasi-isotropic behavior of the GLARE laminate. The delamination shape of each inter-ply interface, therefore, was not necessarily oriented in the fiber direction of the lower ply, which is frequently seen in monolithic composite laminates [45].…”

Section: • C (G C80 = G C0 + (45%*g C0 ))mentioning

confidence: 99%

“…Keeping the interfacial strength, the finer CZEs fail faster [45]. The tendency is opposite when the CZEs are coarser [45]. This non-physical effect of discretization tailbacks to the parameters govern the damage initiation of a cohesive element.…”

Section: Discretizationmentioning

confidence: 99%

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Interface Failure of Heated GLARETM Fiber–Metal Laminates under Bird Strike

Hasan

2020

Aerospace

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Many high-strength composite materials have been developed for aircraft structures. GLAss fiber REinforced aluminum (GLARE) is one of the high-performance composites. The review of articles, however, yielded no study on the impact damage of heated GLARE laminates. This study, therefore, aimed at developing a numerical model that can delineate the continuum damage of GLARE 5A-3/2-0.3 laminates at elevated temperatures. In the first stage, the inter-laminar interface failure of heated GLARE laminate had been investigated at room temperature and 80 °C. The numerical analysis employed a three-dimensional GLARE 5A-3/2-0.3 model that accommodated volumetric cohesive interfaces between mating material layers. Lagrangian smoothed particles populated the projectile. The model considered the degradation of tensile and shear modulus of glass fiber reinforced epoxy (GF/EP) at 80 °C, while incorporated temperature-dependent critical strain energy release rate of cohesive interfaces. When coupled with the material particulars, an 82 m/s bird impact at room temperature exhibited delamination first in the GF/EP 90°/0° interface farthest from the impacted side. Keeping the impact velocity, interface failure propagated at a slower rate at 80 °C than that at room temperature, which was in agreement with the impact damage determined in the experiments. The outcomes of this study will help optimize a GLARE laminate based on the anti-icing temperature of aircraft.

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Section: Discretizationmentioning

confidence: 97%

Section: • C (G C80 = G C0 + (45%*g C0 ))mentioning

confidence: 99%

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Interface Failure of Heated GLARETM Fiber–Metal Laminates under Bird Strike

Hasan

2020

Aerospace

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“…where E is the Young's modulus of the material along the laminate thickness direction, t is the sub-laminate thickness , and M is a non-dimensional number that is to be chosen much larger than one. For cohesive interfaces in non-laminates t is not defined, so in (25) it can be replaced by a certain length measure h of the bulk material [78] or the finite element mesh size. Taking M = 100, E = E 22 = 1.05 × 10 4 N/mm 2 and t = 1.55 mm for the delamination tests (see Section 4), we estimate α 0 ≈ 10 6 N/mm 3 .…”

Section: Cohesive Zone Model Parametersmentioning

confidence: 99%

A Stabilized Finite Element Method for Modeling Mixed-mode Delamination of Composites

Ghosh¹,

Annavarapu²,

Jiménez³

et al. 2017

American Society for Composites 2017

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Delamination of composite materials is commonly modeled using intrinsic cohesive zone models (CZMs), which are generally incorporated into the standard finite element (FE) method through a zero-thickness interface (cohesive) element; however, intrinsic CZMs exhibit numerical instabilities when the cohesive stiffness parameters is assumed to be large relative to the elastic stiffness of the composite material. To address this numerical instability issue, we propose a stabilized finite element method by combining the traditional penalty method with the Nitsche's method that is equally effective for any specified initial stiffness of the cohesive (traction-separation) law. The key advantage of the proposed method is that it generalizes the Nitsche's method to any tractionseparation law with arbitrary large values of initial stiffness and provides a unified way to treat cohesive fracture problems in a variationally consistent and stable manner. We implemented the stabilized method in the commercial finite element software Abaqus via the user element subroutine and simulated benchmark tests for mode I and mixed-mode delamination in isotropic materials to establish the viability of the approach. Ongoing work is aimed at extending the method to model delamination in transversely isotropic laminated composites.

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“…With this modified formulation of the cohesive constitutive law, the dependence of the macro-scale response on the inter-laminar strength can be eliminated but only during the delamination propagation after the peak load. The peak load is still affected by the inter-laminar strength, which is against the conclusion of the study of Lu et al (2019). Lu et al systematically analyzed the effect of inter-laminar strength on the delamination behavior, and it was found that in the presence of a stress concentration, such as a predelamination, the structural response is strength independent including both peak load and the response in the propagation part.…”

Section: Introductionmentioning

confidence: 95%