An integrated continuous–discontinuous approach towards damage engineering in sheet metal forming processes

Mediavilla, J.; Peerlings, R.H.J.; Geers, M.G.D.

doi:10.1016/j.engfracmech.2005.10.011

Cited by 60 publications

(46 citation statements)

References 37 publications

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“…Avoiding penetration requires a self-contact algorithm, which was not available in the present framework. However, computations done using a similar model [43], in an operator-split implementation, showed that the influence of contact between the crack faces is only limited and hardly influences the crack growth direction. Therefore, the simulations shown here were done without self-contact, but the penetration is eliminated in each remeshing step.…”

Section: Arcan Testmentioning

confidence: 99%

Discrete crack modelling of ductile fracture driven by non‐local softening plasticity

Mediavilla

Peerlings

Geers

2006

Numerical Meth Engineering

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SUMMARYA combined approach towards ductile damage and fracture is presented, in the sense that a continuous material degradation is coupled with a discrete crack description for large deformations. Material degradation is modelled by a gradient enhanced damage-hyperelastoplasticity model. It is assumed that failure occurs solely due to plastic straining, which is particularly relevant for shear dominated problems, where the effect of the hydrostatic stress in triggering failure is less important. The gradient enhancement eliminates pathological localization effects which would normally result from the damage influence. Discrete cracks appear in the final stage of local material failure, when the damage has become critical. The rate and the direction of crack propagation depend on the evolution of the damage field variable, which in turn depends on the type of loading. In a large strain finite element framework, remeshing allows to incorporate the changing crack geometry and prevents severe element distortion. Attention is focused on the robustness of the computations, where the transfer of variables, which is needed after each remeshing, plays a crucial role. Numerical examples are shown and comparisons are made with published experimental results.

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Section: Arcan Testmentioning

confidence: 99%

Discrete crack modelling of ductile fracture driven by non‐local softening plasticity

Mediavilla

Peerlings

Geers

2006

Numerical Meth Engineering

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“…Practically this last system is resolved every 100-1000 explicit steps. Such a staggered techniques was previously proposed in [29].…”

Section: Finite Element Formulationmentioning

confidence: 99%

“…Moreover, because of the non-local or gradient enhanced formulation, the excessive strain on the fictitious crack surface leads to an unrealistic extension of the damage field. These problems motivated the introduction of a crack when using a non-local CDM, either by remeshing techniques when the damage is close to one [28,29], or by having recourse to an xFEM scheme [30,31,32], but with a loss of energy. The remeshing technique or a method implying a loss of energy can remain accurate when the crack introduction physically occurs for damage values close to one, but this is not necessarily the case for ductile materials for which the failure was observed experimentally for lower values of the damage.…”

Section: Introductionmentioning

confidence: 99%

“…The consistent and computationally efficient implementation of the non-local implicit CDM-CZM hybrid method is developed within a DG framework in Section 3. A staggered explicit-direct resolution scheme [29] of the finite element model which comprise displacement and non-local degrees of freedom is then proposed in a parallel setting in Section 4. Section 5 illustrates the efficiency of the hybrid non-local implicit DG/ extrinsic cohesive law framework on two standard problems.…”

Section: Introductionmentioning

confidence: 99%

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Elastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework

Becker

Noels

2014

Computer Methods in Applied Mechanics and Engineering

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One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially in their non-local formulation which avoids the loss of solution uniqueness, can capture the material degradation process up to the localization of the damage, but are unable to represent a discontinuity in the structure. On the other hand cohesive zone methods can represent the process zone at the crack tip governing the crack propagation, but cannot account for the diffuse material damaging process.In this paper we propose to combine, in a small deformations setting, a non-local elastic damage model with a cohesive zone model. This combination is formulated within a discontinuous Galerkin finite element discretization. Indeed this DG weak formulation can easily be developed in a non-local implicit form and naturally embeds interface elements that can be used to integrate the traction separation law of the cohesive zone model. The method remains thus consistent and computationally efficient as compared to other cohesive element approaches.The effects of the damage to crack transition and of the mesh discretization are respectively studied on the compact tension specimen and on the double-notched specimen, demonstrating the efficiency and accuracy of the method.

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“…These models, in which the damage is not coupled to the plasticity, have the advantage of being simple to implement in finite element codes and have a small number of parameters to identify. However, it has been shown experimentally that they overestimate the punching loads and are not capable of predicting the damage for complex loading paths and large plastic strain, which is the case for the punching process ( [6,[11][12][13][14][15][16]). …”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical analysis of micromechanical damage in the punching process for High-Strength Low-Alloy steels

Achouri

Germain

Santo

et al. 2014

Materials & Design (1980-2015)

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. b s t r a c tSequential sheet metal forming processes can result in the accumulation of work hardening and damage effects in the workpiece material. The mechanical strength of the final component depends on the ''evolution'' of these two characteristics in the different production steps. The punching process, which is usually in the beginning of the production chain, has an important impact on the stress, strain and damage states in the punched zones. It is essential that the influence of these mechanical fields be taken into account in the simulation of the forming sequence. In order to evaluate the evolution of each phenomenon, and in particular damage accumulation in the forming process, it is essential to characterize the punching process. The objective of this work is to understand and identify the physical damage mechanisms that occur during the punching operation and to establish relevant numerical models to predict the fracture location. The effect of the punch-die clearance on mechanical fields distribution is also discussed in this work.

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An integrated continuous–discontinuous approach towards damage engineering in sheet metal forming processes

Cited by 60 publications

References 37 publications

Discrete crack modelling of ductile fracture driven by non‐local softening plasticity

Discrete crack modelling of ductile fracture driven by non‐local softening plasticity

Elastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework

Experimental and numerical analysis of micromechanical damage in the punching process for High-Strength Low-Alloy steels

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