Stiffness reduction, creep, and irreversible strains in fiber composites tested in repeated interlaminar shear

Pettersson, Kaj; Neumeister, Jonas M.; Gamstedt, E. Kristofer; Öberg, Hans

doi:10.1016/j.compstruct.2006.06.021

Cited by 17 publications

(12 citation statements)

References 10 publications

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“…The reason is believed to be due to the formation of micro cracks and shear hackles (cf. Pettersson et al, 2006). At h = 0°, 15°and 30°, the R n (w)-curves almost coincide.…”

Section: Stress-deformation Relationsmentioning

confidence: 90%

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Mixed mode modeling of a thin adhesive layer using a meso-mechanical model

Salomonsson

2008

Mechanics of Materials

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“…The reason is believed to be due to the formation of micro cracks and shear hackles (cf. Pettersson et al, 2006). At h = 0°, 15°and 30°, the R n (w)-curves almost coincide.…”

Section: Stress-deformation Relationsmentioning

confidence: 90%

“…The buildup of ''adhesive" in the lower right corner of the RVE is experimentally referred to as shear hackles or cusps (cf. Pettersson et al, 2006). The corresponding cracks, for these different mode mixes, orient themselves towards the horizontal plane with increasing mode mix and the shear hackles reduce.…”

Section: The Fracture Processmentioning

confidence: 95%

Mixed mode modeling of a thin adhesive layer using a meso-mechanical model

Salomonsson

2008

Mechanics of Materials

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“…if w = 0. This explains the peel deformation observed in ENFexperiments (Leffler et al 2007), and the shear hackles or cusps observed on fracture surfaces (Pettersson et al 2006). Moreover, if it is assumed that the plasticity is time dependent in nature, it also explains the difference in influence of strain rate on cohesive laws in peel and shear; experiments indicate a much larger rate dependence on the peak stress in shear than in peel (Carlberger et al 2009).…”

Section: Mesomechanical Modellingmentioning

confidence: 91%

Some aspects of cohesive models and modelling with special application to strength of adhesive layers

et al. 2010

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An overview of recent development of cohesive modelling is given. Cohesive models are discussed in general and specifically for the modelling of adhesive layers. It is argued that most cohesive models model a material volume and not a surface. Detailed microscopic and mesomechanical studies of the fracture process of an engineering epoxy are discussed. These studies show how plasticity on the mesomechanical length scale contributes to the fracture energy in shear dominated load cases. Methods to measure cohesive laws are presented in a general setting. Conclusions and conjectures based on experimental and mesomechanical studies are presented. The influence of temperature and strain rate on the peak stress and fracture energy of cohesive laws indicates fundamentally different mechanisms responsible for these properties. Experiments and mesomechanical studies show that in-plane straining of an adhesive layer can give large contributions to the registered fracture energy. Finite element formulations including a method to incorporate this influence are discussed.

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“…For high-cycle fatigue, since individual loading cycles are not analyzed and damage accumulates over several cycles, this assumption of a linear secant behavior is not an issue. For low-cycle fatigue, however, Pettersson et al (2006) report that friction-like processes (sliding, viscosity) contribute to irreversible strains during cycle-by-cycle shear loading experiments, leading to non-secant behavior. The damage mechanics framework employed in the DDZM provides the flexibility to incorporate such non-secant (plastic) unloading behavior.…”

Section: Remarkmentioning

confidence: 94%

A discrete damage zone model for mixed-mode delamination of composites under high-cycle fatigue

et al. 2014

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A discrete damage zone model (DDZM) is developed within the fi nite element framework to simulate mode-mix ratio-and temperature-dependent delamination in laminated composite materials undergoing high cycle fatigue loading. In the DDZM, discrete spring elements are placed at the fi nite element nodes along the laminate interface. Static and fatigue damage laws are used to defi ne the behavior of the spring elements and model irreversible damage growth. The static damage model parameters are obtained from known material properties and fracture mechanics principles. The fatigue damage model parameters are obtained by calibrating the model to fi t published experimental data, and the variation of fatigue parameters with mode-mix ratio is given by a quadratic relation. The DDZM predicts crack growth rates that are in agreement with those given from published literature in which a quadratic relation is used to obtain Paris law parameters for different mode-mix ratios, thus validating the approach. Temperature dependance is implemented using an Arrhenius relation for fatigue damage model parameters, and the critical fracture energy varies with temperature as well. Although the model captures the temperature effects on delamination for mode I and 50% mode II, the prediction deviates from experiments for pure mode II, because the corresponding damage mechanism entirely changes with temperature. The DDZM converges upon mesh refi nement, given that the mesh size used for calibrating model parameters is suffi ciently small. The mechanisms driving static and fatigue damage for different static model parameters (i.e., initial stiffness and critical separation) and their infl uence on overall damage growth are also investigated. It was found that for a low initial spring stiffness fatigue damage dominates the total damage growth, whereas for a large initial stiffness static damage dominates. For intermediate initial stiffnesses, the growth of static and fatigue damage becomes sensitive to mesh size, and model convergence is diffi cult to attain.

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Stiffness reduction, creep, and irreversible strains in fiber composites tested in repeated interlaminar shear

Cited by 17 publications

References 10 publications

Mixed mode modeling of a thin adhesive layer using a meso-mechanical model

Mixed mode modeling of a thin adhesive layer using a meso-mechanical model

Some aspects of cohesive models and modelling with special application to strength of adhesive layers

A discrete damage zone model for mixed-mode delamination of composites under high-cycle fatigue

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