Strategies for stiffness analysis of laminates with microdamage: combining average stress and crack face displacement based methods

Vārna, Jānis

doi:10.1002/zamm.201400296

Cited by 20 publications

(14 citation statements)

References 30 publications

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“…On the other hand, samples of recent results for the damage-mechanics-based approach may be found, e.g., in [11] for a multicrack elastoplastic damage model; in [12] for micro-mechanical studies of damage; in [13] for stiffness degradation analysis of laminates with micro-damage; and in [14] for ductile damage accumulation; and many others.…”

Section: Introductionmentioning

confidence: 99%

Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Zhan

Wang

et al. 2019

Z Angew Math Mech

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A new finite strain elastoplastic 2 -flow model is proposed toward directly simulating cyclic and non-cyclic failure effects of metals. The main novelties of this model are as follows:(1) The usual notion of yielding is rendered irrelevant in a more realistic sense of representing elastoplastic behaviors of metals up to failure;(2) The thermodynamic consistency requirement from the second law may be identically fulfilled;(3) Failure effects under cyclic and non-cyclic conditions may be automatically incorporated as inherent constitutive features, with involving neither additional variables nor ad hoc failure criteria;(4) Hardening-to-softening effects of metals up to failure may be effectively characterized in a unified manner.Simulation results are provided and compared with experimental data for monotonic and cyclic failure effects for both uniaxial and torsional deformation modes. In particular, both the Swift effects and the failure effects of twisted metal tubes are simultaneously simulated for four cases of finite torsion, including free-end and fixed-end torsion under monotonic and cyclic loadings, and accurate agreement with finite strain data for both torsional modes is accomplished for the first time.

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Section: Introductionmentioning

confidence: 99%

Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Zhan

Wang

et al. 2019

Z Angew Math Mech

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“…This configuration will be used in this article to produce numerical data needed for CSD analysis and for validation. Therefore, we present the expressions obtained by analytical treatment of expressions in “Formulation of the problem and summary of results of the GLOB-LOC approach” section for this relatively simple case of damaged laminates (Loukil et al., 2013; Pupurs et al., 2016; Varna, 2015) …”

Section: Determination Of Thermo-elastic Constants In Glob-loc Formulmentioning

confidence: 99%

“…Therefore, approximate fitting expressions for COD and CSD based on finite element method (FEM) results were suggested in Lundmark and Varna (2005, 2006). Instead of COD and CSD the average perturbation stresses can be used as an input in GLOB-LOC: they are linearly linked to the COD and CSD (Varna, 2015). This finding allows using any approximate analytical model for determination of the whole set of laminate thermo-elastic constants.…”

Section: Introductionmentioning

confidence: 99%

Crack face sliding displacement (CSD) as an input in exact GLOB-LOC expressions for in-plane elastic constants of symmetric damaged laminates

Loukil

Vārna

2019

International Journal of Damage Mechanics

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The crack opening and crack sliding displacements of both faces of an intralaminar crack are the main parameters defining the significance of each crack in laminate stiffness degradation, according to the previously published GLOB-LOC approach for symmetric laminates with an arbitrary number of cracks in all plies. In the exact stiffness expressions of this approach, the crack density is always multiplied by crack opening displacement and crack sliding displacement. The dependence of crack opening displacement on geometrical and elastic parameters of adjacent plies was studied previously and described by simple fitting functions. The crack sliding displacement has been analyzed for low-crack densities only and the proposed finite element method-based fitting expressions are oversimplified not including the out-of-plane ply stiffness effects. Based on finite element method analysis, more accurate expressions for so-called non-interactive cracks are suggested in the presented article. For the first time the shear stress perturbations are analyzed and interaction functions are presented with the feature that they always lead to slightly conservative predictions. The presented simple fitting functions, when used in the GLOB-LOC model, give predictions that are in a good agreement with finite element method results and with experimental data for laminates with damaged off-axis plies in cases when crack face sliding is of importance. The significance of including crack sliding displacement in stiffness predictions is demonstrated.

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“…for cohesive zone models and for non‐cohesive interface models; in Stoughton and Yoon for failure criterion for sheet metals; in Sun et al . for fatigue crack growth rate in metallic materials; in [] for crack face displacement based methods in stiffness analysis of laminates; in [] for propagation of a curvilinear crack with interfacial bonds; and many others.…”

Section: Introductionmentioning

confidence: 99%

“…for a modified damage model; in Malcher et al . for a study of ductile fracture; in [] for stiffness analysis of laminates with microdamage; and many others.…”

Section: Introductionmentioning

confidence: 99%

Direct simulation of thermo‐coupled fatigue failure for metals

Zhan

Wang

et al. 2018

Z Angew Math Mech

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A new finite strain elastoplastic J2−flow model with thermo‐coupled effects is proposed for the purpose of simulating cyclic and non‐cyclic thermo‐coupled fatigue failure behavior of metals. Novelties in four respects are incorporated in the proposed model: (i) the usual notion of yielding is rendered irrelevant with a smooth transition from the elastic to the plastic state; (ii) the thermodynamic consistency stipulated by the second law is identically ensured; (iii) asymptotic loss of the strength in cyclic and non‐cyclic thermomechanical processes is incorporated as inherent constitutive features; and, accordingly, (iv) the fatigue failure behavior may be derived as direct consequences of the proposed model, without involving any additional failure criteria and any additional variables. Thermo‐coupled responses of a metal bar with two fixed ends under cyclic heating and cooling over various temperature ranges are studied based on a simple case of the proposed model. Results are obtained for the maximum tensile and compressive stresses changing with the cycle number and, in particular, for the thermal fatigue life versus the temperature amplitude. Model predictions compare well with test data.

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Strategies for stiffness analysis of laminates with microdamage: combining average stress and crack face displacement based methods

Abstract: Region of very high crack density is often called saturation region because due to interaction of stress perturbations cracking stops. The saturation spacing between cracks is approximately equal to t k and, hence, the maximum possible normalized crack density ρ knmax ≈ 1.

Cited by 20 publications

References 30 publications

Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Crack face sliding displacement (CSD) as an input in exact GLOB-LOC expressions for in-plane elastic constants of symmetric damaged laminates

Direct simulation of thermo‐coupled fatigue failure for metals

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Strategies for stiffness analysis of laminates with microdamage: combining average stress and crack face displacement based methods

Abstract: Region of very high crack density is often called saturation region because due to interaction of stress perturbations cracking stops. The saturation spacing between cracks is approximately equal to t k and, hence, the maximum possible normalized crack density ρ knmax ≈ 1.

Cited by 20 publications

References 30 publications

Innovative elastoplastic J2‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Innovative elastoplastic J2‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Crack face sliding displacement (CSD) as an input in exact GLOB-LOC expressions for in-plane elastic constants of symmetric damaged laminates

Direct simulation of thermo‐coupled fatigue failure for metals

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Product

Resources

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Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features

Innovative elastoplastic J₂‐flow model incorporating cyclic and non‐cyclic failure effects of metals as inherent constitutive features