An evaluation of the MPM for simulating dynamic failure with damage diffusion

Chen, Zhen; Hu, Wenqing; Shen, Luming; Xin, Xiangpeng; Brannon, Rebecca M.

doi:10.1016/s0013-7944(02)00066-8

Cited by 69 publications

(43 citation statements)

References 10 publications

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“…Therefore, the convergence behaviour of the integrator used is similar to that employed to integrate the corresponding equations in fem. However, according to Chen et al [36], no consistent theoretical results have been obtained for the convergence behaviour of time integrators when larger deformations occur and a reasonable time step is usually found through numerical experiments.…”

Section: Stabilitymentioning

confidence: 98%

Discrete and continuum modelling of soil cutting

Coetzee

2014

Comp. Part. Mech.

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Both continuum and discrete methods are used to investigate the soil cutting process. The Discrete Element Method (dem) is used for the discrete modelling and the Material-Point Method (mpm) is used for continuum modelling. Mpmis a so-called particle method or meshless finite element method. Standard finite element methods have difficulty in modelling the entire cutting process due to large displacements and deformation of the mesh. The use of meshless methods overcomes this problem. Mpm can model large deformations, frictional contact at the soil-tool interface, and dynamic effects (inertia forces). In granular materials the discreteness of the system is often important and rotational degrees of freedom are active, which might require enhanced theoretical approaches like polar continua. In polar continuum theories, the material points are considered to possess orientations. A material point has three degrees-of-freedom for rigid rotations, in addition to the three classic translational degrees-of-freedom. The Cosserat continuum is the most transparent and straightforward extension of the nonpolar (classic) continuum. Two-dimensional dem and mpm (polar and nonpolar) simulations of the cutting problem are compared to experiments. The drag force and flow patterns are compared using cohesionless corn grains as material. The corn macro (continuum) and micro (dem) properties were obtained from shear and oedometer tests. Results show that the dilatancy angle plays a significant role in the flow of material but has less of an influence on the draft force. Nonpolar mpm is the most accurate in predicting blade forces, blade-soil interface stresses and the position and orientation of shear bands. Polar mpm fails in predicting the orientation of the shear band, but is less sensitive to mesh size and mesh ori-C. J. Coetzee (B) Department of Mechanical and Mechatronic Engineering, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa e-mail: ccoetzee@sun.ac.za entation compared to nonpolar mpm. dem simulations show less material dilation than observed during experiments.

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Section: Stabilitymentioning

confidence: 98%

Discrete and continuum modelling of soil cutting

Coetzee

2014

Comp. Part. Mech.

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“…(Chen 1996;Chen et al 2005), the computational efficiency of decohesion modeling is improved by prescribing the critical normal and tangential decohesion strengths directly, without performing discontinuous bifurcation analysis in each time step, to predict the post-peak response with a single-processor personal computer. The MPM (Chen et al 2002;Sulsky et al 1994) is employed to simulate the three-dimensional evolution of failure from microcracking to macrocracking without the need for remeshing.…”

Section: Blind Predictionsmentioning

confidence: 99%

The Sandia Fracture Challenge: blind round robin predictions of ductile tearing

et al. 2014

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Existing and emerging methods in computational mechanics are rarely validated against problems with an unknown outcome. For this reason, Sandia National Laboratories, in partnership with US National Science Foundation and Naval Surface Warfare Center Carderock Division, launched a computational challenge in mid-summer, 2012. Researchers and engineers were invited to predict crack initiation and propagation in a simple but novel geometry fabricated from a common off-the-shelf commercial engineering alloy. The goal of this international Sandia Fracture Challenge was to benchmark the capabilities for the prediction of deformation and damage evolution associated with ductile tearing in structural metals, including physics models, computational methods, and numerical implementations currently available in the computational fracture community. Thirteen teams participated, reporting blind predictions for the outcome of the Challenge. The simulations and experiments were performed independently and kept confidential. The methElectronic supplementary material The online version of this article (doi:10.1007/s10704-013-9904-6) contains supplementary material, which is available to authorized users.Sandia National Laboratories, Albuquerque, NM, USA e-mail: blboyce@sandia.gov ods for fracture prediction taken by the thirteen teams ranged from very simple engineering calculations to complicated multiscale simulations. The wide variation in modeling results showed a striking lack of consistency across research groups in addressing problems of ductile fracture. While some methods were more successful than others, it is clear that the problem of ductile fracture prediction continues to be challenging. Specific areas of deficiency have been identified through this effort. Also, the effort has underscored the need for additional blind prediction-based assessments.

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“…Therefore, the convergence behaviour of the integrator used is similar to that employed to integrate the corresponding equations in FEM. However, according to Chen et al [14], no consistent theoretical results have been obtained for the convergence behaviour of time integrators when larger deformations occur and a reasonable time step is usually found through numerical experiments.…”

Section: Stabilitymentioning

confidence: 98%

The modelling of anchors using the material point method

Coetzee

Vermeer

Basson

2005

Num Anal Meth Geomechanics

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SUMMARYThe ultimate capacity of anchors is determined using the material point method (MPM). MPM is a socalled meshless method capable of modelling large displacements, deformations and contact between different bodies. A short introduction to MPM is given and the derivation of the discrete governing equations. The analysis of a vertically loaded anchor and one loaded at 458 is presented. The loaddisplacement curves are compared to that obtained from experiments and the effect of soil stiffness and anchor roughness is investigated. The results of the vertically loaded anchor are also compared to an analytical solution. The displacement of the soil surface above the anchor was measured and compared to the numerical predictions.Convergence with mesh refinement is demonstrated and the effect of mesh size and dilatancy angle on the shear band width and orientation is indicated.The results show that MPM can model anchor pull out successfully. No special interface elements are needed to model the anchor-soil interface and the predicted ultimate capacities were within 10% of the measured values.

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An evaluation of the MPM for simulating dynamic failure with damage diffusion

Cited by 69 publications

References 10 publications

Discrete and continuum modelling of soil cutting

Discrete and continuum modelling of soil cutting

The Sandia Fracture Challenge: blind round robin predictions of ductile tearing

The modelling of anchors using the material point method

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