The dynamic response of edge clamped plates loaded by spherically expanding sand shells

• Published in: International journal of impact engineering 2013-12, Vol.62, p.182-195
• Main Authors: Dharmasena, Kumar P., Wadley, Haydn N.G., Liu, Tao, Deshpande, Vikram S.
• Format: Article
• Language: English
• Subjects: Computer simulation; Deflection; Discrete particle simulation; Drying; Finite element analysis; Fluid–structure interaction; Impulse loading; Plates; Sand; Sandwich construction; Sandwich panels; Shells; Simulation
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2013.06.012

The dynamic deformation of both edge clamped stainless steel sandwich panels with a pyramidal truss core and equal mass monolithic plates loaded by spherically expanding shells of dry and water saturated sand has been investigated, both experimentally and via a particle based simulation methodology. The spherically expanding sand shell is generated by detonating a sphere of explosive surrounded by a shell of either dry or water saturated synthetic sand. The measurements show that the sandwich panel and plate deflections decrease with increasing stand-off between the center of the charge and the front of the test structures. Moreover, for the same charge and sand mass, the deflections of the plates are significantly higher in the water saturated sand case compared to that of dry sand. For a given stand-off, the mid-span deflection of the sandwich panel rear faces was substantially less than that of the corresponding monolithic plate for both the dry and water saturated sand cases. The experiments were simulated via a coupled discrete-particle/finite element scheme wherein the high velocity impacting sand is modeled by interacting particles while the plate is modeled within a Lagrangian finite element setting. The simulations are in good agreement with the measurements for the dry sand impact of both the monolithic and sandwich structures. However, the simulations underestimate the effect of stand-off in the case of the water saturated sand explosion, i.e. the deflections decrease more sharply with increasing stand-off in the experiments compared to the simulations. The simulations reveal that the momentum transmitted into the sandwich and monolithic plate structures by the sand shell is approximately the same, consistent with a small fluid–structure interaction effect. The smaller deflection of the sandwich panels is therefore primarily due to the higher bending strength of sandwich structures. •Lattice core sandwich panel responses to impact by sand shells is investigated.•The effects of varying the stand-off distance and sand moisture are reported.•The deflections of sandwich panels are less than those of equivalent solid plates.•Coupled particle-FEM simulations are used to analyze the experiments.•The study shows that the modeling approach is very successful for dry sand loadings.