Modeling & Simulation, Testing & Validation Co-Simulation of MBD Models with DEM Code to Predict Mobility on Soft Soil Brian Edwards – Pratt & Miller Engineering Sophie Broad – DEM Solutions 8/22/2018
Mobility of MBD Models on Modeling & Simulation, Testing & Validation Soft Soil • Pratt & Miller designs, builds and tests wheeled and tracked vehicles • Current full-vehicle simulation capabilities are limited to hard surfaces • Collaboration between Pratt & Miller, DEM Solutions, and MSC.Software to develop expertise in simulating full MBD models on deformable terrains 8/22/2018
Discrete Element Modeling of Modeling & Simulation, Testing & Validation Soft Soils Discrete Finite Element Analysis Element Modeling Discrete Element Modeling Captures the dual-nature of bulk materials that behave like both a solid and a fluid Computational Fluid Dynamics 8/22/2018
EDEM Bulk Material Modeling & Simulation, Testing & Validation Modeling Software Market-leading bulk materials simulation software Easy-to-use, GUI driven set-up Optimized GPU & CPU solvers Wide range of analysis tools 8/22/2018
Modeling & Simulation, EDEM Particle Model Testing & Validation Particle Model Poisson’s Ratio 0.25 Solids Density 2600 kg/m^3 Shear Modulus 1.0 E+07 Pa Particle to Particle Interaction Coeff. of Restitution 0.5 Coeff. of Static Friction 1.0 Coeff. of Rolling Friction 0.15 Particle to Geometry Interaction Coeff. of Restitution 0.75 Coeff. of Static Friction 0.44 Coeff. of Rolling Friction 0.20 8/22/2018
Adams MBD Models of Wheeled and Modeling & Simulation, Testing & Validation Tracked Vehicles HMMWV (Humvee) Medium-sized Tank Vehicle mass: 2700 kg 3.7m long by 1.5m wide by 1.3m tall Wheelbase: 2.23 m Track center-to-center: 1.2 m Track width: 1.30 m Track segment width: 0.3m Tires: 37x12 50R16 5 road wheels, idler, and 2 support rollers 35 psi on hard surface 84 track segments and connectors Rigid geometry on soft soil 8/22/2018
Modeling & Simulation, Soft Soil Terrains Testing & Validation Flat particle bed 30 percent side-slope Single hill terrain 20 percent grade climb Double hill terrain 8/22/2018
Adams/EDEM Co-Simulation Modeling & Simulation, Testing & Validation Process A configuration file defines interactions between Adams geometries and EDEM soil particles Adams calculates body displacements and passes geometry positions to EDEM, which calculates bulk particle forces and returns them to Adams 8/22/2018
Wheeled Vehicle Co- Modeling & Simulation, Testing & Validation Simulation Results HMMWV on Flat Terrain at 20kph HMMWV on Double-Hill at 25mph HMMWV on 30% Side Slope at 15mph 8/22/2018
Tracked Vehicle Co- Modeling & Simulation, Testing & Validation Simulation Results Tank Single Hill at 10mph Tank Double Hill at 9mph Tank Double Hill at 7mph 8/22/2018
Tracked Vehicle Co- Modeling & Simulation, Testing & Validation Simulation Results Tank Pivot Steer at 3mph Tank on 20% grade at Half Throttle Tank 2 nd Pass at 3mph Tank Draw-Bar Pull at Full Throttle 8/22/2018
Modeling & Simulation, Physical Test Bed – Small Robotic Platform Testing & Validation Test Bed: • 27 feet by 27 feet by 2 feet • Pea stone ¼ inches to ¾ inches • 2 foot tall concrete blocks on sides Side Hill Straight-line Turning Radius 8/22/2018
Modeling & Simulation, DARPA GXV-T METS Soft Soil Modeling Testing & Validation • G round X - V ehicle T echnologies • M ulti-mode E xtreme T ravel S uspension 8/22/2018
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