Predictive Engineering LS-DYNA DEM and SPH Simulation Project Work

Analysis
Objective
This case study presents several examples where we have used the discrete element method (DEM) and smooth particle hydrodynamics (SPH) to apply sand and rock, mineral, organic (bird strike) and fluid loading to complex nonlinear dynamic finite element models.
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.
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The video provides a graphical overview of the DEM and SPH process that has been used at Predictive Engineering with examples of project work with direct examples of:
- Using DEM as an integral part of a simulation to predict the cushioning effect of sand and rocks (DEM particles) when a very large rock (rigid body) is dropped onto an apron feeder (FEA) that is commonly used in an open pit mining operation;
- DEM impact simulation of dropped mineral cake onto conveyor;
- Mineral flow prediction on conveyor with knife gate with prediction of maximum forces onto the knife gate and if the gate would get buried by conveyed material;
- Virtual DEM angle-of-repose calibration to experimental test;
- SPH simulation of bird strike on composite radome;
- SPH fluid sloshing in ASME Section VIII, Division 2 pressure vessel.









