Novel procedure to validate MPM results by means of PIV measurements

Abstract

The Particle Image Velocimetry is a powerful non-invasive technique to analyse displacements in experimental tests. Displacement increments elapsed between the capture of two digital images are commonly measured on points of a predefined grid fixed in the space. Therefore, tracking the movement of physical particles, which is interesting information especially in cases dealing with large displacements, is not possible when using this procedure. A post-processing code has been developed to get accumulated displacements, incremental and accumulated strains, as well as other variables such as velocity and acceleration, in points that represent a portion of the deformable object analysed. The procedure is of interest specially when dealing with large displacements. The method presented is especially useful to compare experimental measurements with MPM numerical results. The variables from the numerical model stored in material points can be directly compared with the experimental measurements obtained by means of the post-process code presented in the paper. The methodology is applied for the analysis of the failure of a dry granular slope performed in a 1 g scaled laboratory test which is numerically modelled with an MPM code (GeoPart). The aim of the paper is to show the capabilities of the new PIV interpretation procedure by comparing experimental and numerical results. The accuracy of the MPM model presented is not the main focus of the paper, but some limitations of the model are highlighted.