Simulation of the bending process of hardening metallic sheets using damage model. Part I: Theoretical development and numerical implementation

Bending is an important forming process for ultra-high strength steel (UHSS) because it is cost-effective, fast and in many cases it can be used to replace welding in a part manufacturing processes. One major challenge in air bending of UHSS is to predict the limits for bendability since the traditional methods for failure prediction, such as forming limit diagram (FLD), cannot generally be applied to bending process. In this paper, 3D FE-modelling coupled with a CDM-damage model is used to simulate the air bending process and to determine the bendability limits for a hot-rolled 960MPa grade. Damage parameters for the CDM-model are determined by using optical strain measurements and inverse modelling of the tensile test. Three point bending tests with optical strain measuring were carried out to determine the deformation field of the outer bend in different bending angles and the results of the bending simulation are compared with the strain measurements of the bending tests. The damage model is then calibrated using the experimental results of the bending tests to adjust the crack occurrence in the simulation. A good agreement was found between simulations and experimental measurements.

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On the numerical implementation of a finite strain anisotropic damage model based upon the logarithmic rate

Revue Européenne des Éléments Finis ◽

10.1080/12506559.2001.11869258 ◽

2001 ◽

Vol 10 (2-4) ◽

pp. 385-400

Author(s):

Otto Timme Bruhns ◽

Christian Ndzi Bongmba

Keyword(s):

Finite Strain ◽

Damage Model ◽

Anisotropic Damage ◽

Numerical Implementation ◽

Model Based

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A Coupled Elastoplastic Damage Model for Clayey Rock and Its Numerical Implementation and Validation

Geofluids ◽

10.1155/2020/9853782 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Shanpo Jia ◽

Zhenyun Zhao ◽

Guojun Wu ◽

Bisheng Wu ◽

Caoxuan Wen

Keyword(s):

Damage Model ◽

Clayey Rock ◽

Triaxial Tests ◽

Numerical Implementation ◽

Integration Algorithm ◽

Stress Criterion ◽

Proposed Model ◽

Maximal Tensile Stress ◽

Nonlinear Hardening ◽

Elastoplastic Damage

This paper presents a new constitutive model for describing the strain-hardening and strain-softening behaviors of clayey rock. As the conventional Mohr-Coulomb (CMC) criterion has its limitation in the tensile shear region, a modified Mohr-Coulomb (MMC) criterion is proposed for clayey rock by considering the maximal tensile stress criterion. Based on the results of triaxial tests, a coupled elastoplastic damage (EPD) model, in which the elastic and plastic damage laws are introduced to describe the nonlinear hardening and softening behaviors, respectively, is developed so as to fully describe the mechanical behavior of clayey rock. Starting from the implicit Euler integration algorithm, the stress-strain constitutive relationships and their numerical formulations are deduced for finite element implementation in the commercial package ABAQUS where a user-defined material subroutine (UMAT) is provided for clayey rock. Finally, the proposed model is used to simulate the triaxial tests and the results validate the proposed model and numerical implementation.

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Numerical Implementation of Spatial Elastoplastic Damage Model of Concrete in the Framework of Isogeometric Analysis Approach

Mathematical Problems in Engineering ◽

10.1155/2016/4273024 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13

Author(s):

Cheng Ma ◽

Wei-zhen Chen ◽

Jian-yuan Sun

Keyword(s):

Isogeometric Analysis ◽

Geometric Modeling ◽

Damage Model ◽

Internal Variables ◽

Flow Rule ◽

Equilibrium Path ◽

Numerical Implementation ◽

Mapping Algorithm ◽

Solution Algorithms ◽

Elastoplastic Damage

This paper is a study of the numerical implementation of the spatial elastoplastic damage model of concrete by isogeometric analysis (IGA) method from three perspectives: the geometric modeling and the numerical formulation via IGA method, the constitutive model of concrete, and the solution algorithms for the local and global problems. The plasticity of concrete is considered on the basis of a nonassociated flow rule, where a three-parameter Barcelona yield surface and a modified Drucker-Prager plastic potential are used. The damage evolution of concrete driven by the internal variables is expressed by a piecewise function. In the study, the return-mapping algorithm and the substepping strategy are used for stress updating, and a new dissipation-based arc-length method with constraint path that considers the combined contribution of plasticity and damage to the energy dissipation is employed to trace the equilibrium path. After comparisons between simulation results and experimental data, the use of the elastoplastic damage model in the framework of IGA approach is proven to be practical in reflecting material properties of concrete.

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