Comparison of local and nonlocal regularization approaches in Eulerian-based finite element analyses

Abstract

Finite element (FE) results might suffer from significant mesh dependency, especially when modeling shear bands in strain-softening soils. On the other hand, the shear bands in the field are generally thin. The computational costs might dramatically increase when modeling such thin shear bands, especially for large-scale problems, such as progressive landslides. To overcome these issues, FE analyses are generally performed with larger shear band thicknesses by adopting ‘softening scaling’ rules based on local and nonlocal (averaged) strains at the shear bands. The present study compares the performances of local and nonlocal approaches, with a specific focus on softening scaling and large deformation. Analyses are performed using a Eulerian-based FE program, which can model large strains in the shear band without numerical issues related to mesh distortion. Implementing strain-softening behavior in local and nonlocal methods, two idealized cases are simulated: (i) biaxial compression test, (ii) slope failure due to upslope surface loading. FE simulations show that the macroscopic response (i.e., load–displacement behavior) can be modeled using both local and nonlocal regularization techniques. Shear band thickness increases with the progress of shearing. In local analysis, mesh orientation has a considerable effect on shear band thickness. The existence of neighboring shear bands could affect nonlocal strain calculation and the simulation results.