Identification methodology and comparison of phenomenological ductile damage models via hybrid numerical–experimental analysis of fracture experiments conducted on a zirconium alloy

“…Several recent models have been extensively developed and validated for different applications, both for uncoupled models (e.g. Bai and Wierzbicki, 2008;Cao et al, 2015a,b, modified MohrCoulomb (Bai andWierzbicki, 2010;Dunand and Mohr, 2011;Cao et al, 2013)) and coupled models (e.g. Xue model -Xue, 2007;Cao, 2014; Lode-dependent enhanced Lemaitre model - Cao et al, 2014a).…”

Section: Introductionmentioning

confidence: 99%

A model for ductile damage prediction at low stress triaxialities incorporating void shape change and void rotation

Cao

Mazière

Danas

et al. 2015

International Journal of Solids and Structures

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International audienceDuctile fracture at the high triaxiality regime is well-known to be controlled by void nucleation, growth and coalescence. However, under low stress triaxiality conditions and general three dimensional finite deformations, damage is still poorly predicted due to the complex loading state and microstructural changes under such a condition. Experimental results have revealed not only void growth, but also important void shape change and void rotation under shear-dominated loading. The ability of ductile damage models to predict both void growth with shape change and void rotation is thus crucial for complex loading applications. In the present study, a Gurson-like nonlinear homogenization-based model (namely GVAR) is proposed and compared with the constitutive models for elasto-plastic porous materials developed in Kailasam and Ponte Castañeda (1998) (VAR model) and Danas and Aravas (2012) (MVAR model). The proposed model is based on ad hoc modifications of the VAR model, to give sufficiently accurate results for void growth at both low and high stress triaxialities and keeping the functional form of the original Gurson model. The VAR and MVAR models were based on rigorous linear comparison composite (LCC) homogenization methods, which can describe the evolution of microstructure of porous materials, represented by the void volume fraction, the aspect ratios and the orientations of general ellipsoidal voids. The proposed GVAR model thus inherits these characteristics and provides a sufficiently accurate void growth formulation (and simple at the same time). In addition, the loading direction is not necessary aligned with the ellipsoidal void axes. These models are implemented in an object-oriented finite element (FE) code. The identification of model parameters and the assessment of the proposed model are then carried out via 3D periodic unit-cell computations subjected to different stress states. Comparative results show that the present model predicts relatively accurately the evolution of void volume fraction, void aspect ratios and void rotation for different initial void shapes, void volume fractions and under different stress triaxiality levels. A qualitative application to a tensile test on a notched round bar shows the efficiency of the model to predict microstructure evolution (i.e. voids volume, shape and orientation) in a real-scale model simulation. This model with few parameters to be identified is thus promising to predict damage under complex loading paths and ready to be applied to complex FE simulations

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“…In the industry, predicting ductile fracture is usually based on simulations using macroscopic ductile damage models, which are calibrated using experiments where measures are also taken at the macroscale. Example of model which covers such use is the Lemaitre damage model, for which a detailed implementation from experimental calibration to numerical simulation can be found in [1]. In [2], this model was applied to several multi-pass industrial processes and compared to the Gurson-Tvergaard-Needleman microscopic ductile damage model [3,4].…”

Section: Introductionmentioning

confidence: 99%

A new body-fitted immersed volume method for the modeling of ductile fracture at the microscale: Analysis of void clusters and stress state effects on coalescence

Shakoor

Bernacki

Bouchard

2015

Engineering Fracture Mechanics

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International audienceIn this work, a new finite element framework is developed and applied to the study and modeling of ductile fracture mechanisms at the microscale. More particularly, a body-fitted meshing and remeshing methodology is introduced and applications to void coalescence are investigated. Though most studies focus on periodic arrangements of voids, it was proven in experiments as in simulations that random void clusters have a major influence on void growth and coalescence. With the method proposed in this paper, various void arrangements can be addressed and their effect on void growth and coalescence can be studied at large plastic strain and various stress states

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Identification methodology and comparison of phenomenological ductile damage models via hybrid numerical–experimental analysis of fracture experiments conducted on a zirconium alloy

Cited by 57 publications

References 45 publications

Characterization of ductile damage for a high carbon steel using 3D X-ray micro-tomography and mechanical tests – Application to the identification of a shear modified GTN model

Characterization of ductile damage for a high carbon steel using 3D X-ray micro-tomography and mechanical tests – Application to the identification of a shear modified GTN model

A model for ductile damage prediction at low stress triaxialities incorporating void shape change and void rotation

A new body-fitted immersed volume method for the modeling of ductile fracture at the microscale: Analysis of void clusters and stress state effects on coalescence

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