Can LS-DEM be Used to Simulate Cyclic Behavior of Sand?

Abstract

The suitability of LS-DEM to simulate drained and undrained cyclic behavior of sand is evaluated in this paper. A digital twin of a small specimen of the Hostun sand is used to simulate the cyclic average (macroscopic) response along idealized stress and strain paths, representing oedometer, drained and undrained triaxial conditions. The results are here only qualitatively evaluated based on comparison with real test data of different sands, since a) cyclic laboratory tests have not been performed on the actual specimen, and b) relatively low contact stiffness was used in this preliminary analysis in order to reduce the computational cost. The oedometer curves during virgin loading, unloading and re-loading and the cyclic secant stiffnesses during drained cyclic loading were captured qualitatively, but were significantly softer than the experimental ones. From the simulation of a drained cyclic triaxial test the development of accumulated volumetric strain seems reasonable, and the computed response during a cyclic constant volume (undrained) triaxial test looks very promising. Based on this initial study, more detailed LS-DEM simulations will therefore be carried out to improve the understanding of cyclic behavior of saturated sand.