DEM and SPH are both visualized as small discrete spheres but that is about all they have in common since DEM is often used for modeling discrete particles such as rocks or pea pods while SPH is used for modeling continua such as fluids and solids. Where we have found DEM and SPH useful is as a method to apply dynamic loads to structures. For DEM simulations, the ability to simulate granular media from sand and rocks or to friable compressed mineral cake or to food products, has allowed us to create FEA simulations that are far more accurate than what can be achieved by any combination of time varying force, acceleration or pressure loading arrangement. With SPH and its ability to simulate the mechanical response of highly deformable media (e.g., hail or frozen birds) during impact or fluids sloshing within a tank with good accuracy and low numerical cost provides a ready means for performing bird strike analyses or hail impact analyses or fluid sloshing analyses.
This case study is provided as a standalone document but is best accompanied by the video we have posted on YouTube which provides an overview of the DEM and SPH process and some examples of how we have used it at Predictive Engineering.
Keywords: Femap, LS-DYNA, discrete element method (DEM), smooth particle hydrodynamics (SPH), finite element analysis, drop-test, bird strike analysis, hail impact analysis, DEM analysis of rock and sand, DEM calibration to experimental tests, finite element analysis, nonlinear analysis, FSI Analysis, DEM to FEA, ASCE 4-98, sloshing analysis of ASME Section VIII, Division 2 pressure vessel, off-shore platform mounted pressure vessels,