Comparison of Two Mesh Regularization Approaches for Large Deformation Finite Element Analysis-Paper

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The study compares two methods for reducing mesh-dependent results in large-deformation finite-element (FE) analyses of strain-softening soils: element-size scaling and the nonlocal method. Both were implemented in an Eulerian-based FE approach, which allows soil to deform substantially without mesh distortion.<br /><br />The methods were evaluated under undrained conditions in two idealized problems: axial compression of a weak block and slope failure triggered by upslope loading. Without regularization, failure patterns and force–displacement responses varied considerably with mesh size. Both techniques substantially reduced this sensitivity and produced comparable force–displacement curves across mesh sizes.<br /><br />Element-size scaling adjusts the plastic strain required for strength degradation according to element thickness. It was relatively simple and computationally efficient, but did not control shear-band thickness as consistently as the nonlocal method. The nonlocal approach averages plastic shear strain over a surrounding region; it provided better control of shear-band width and reduced mesh sensitivity when the mesh was sufficiently fine. However, it was far more computationally demanding: in one slope analysis, a fine-mesh run took 11 hours with the nonlocal method, compared with 20 minutes using element-size scaling.<br /><br />Overall, both methods can improve large-deformation FE analyses of strain-softening soils. Element-size scaling may be more practical for large problems with limited computing resources, while the nonlocal method offers stronger control of localization at a substantial computational cost. The study is limited to two idealized examples; further comparisons with other numerical approaches are needed.

Keywords

finite element analysis

strain-softening soils

mesh dependency

element-size scaling

nonlocal method

Eulerian approach

large deformation

shear band

slope failure

undrained conditions