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Hybrid Lattice Particle Modeling (HLPM) of Dynamic Fragmentation of Solids Investigator: Ge Wang (gewang0419@gmail.com)

MotivationsMechanical behavior of a solid material is controlled by its microstructure. Complex macroscopic behaviors, such as fracture and failure, arise from microstructure interactions. Thus, if the microstructure and the microstructural interactions within a numerical model could be correctly and accurately replicated, then that model should precisely reproduce the macroscopic behaviors. However, current computing power limits the size of the atomic ensemble to numbers of atoms that are too small to be useful for most engineering-scale systems. Hybrid Lattice Particle Modeling (HLPM) is developed to directly mimic microstructural features and can be executed in reasonable times on standard computers.

Model Introduction HLPM is a dynamic simulation that uses small discrete solid physical particle (or quasi-molecular particles) as a representation of a given fluid or solid. Different particle interaction schemes and mesh structures can be adopted.

Interactions of HLPM

Linear Non-linear: (a) Polynomial (b) Lennard–Jones

Validations of HLPM

(a) Epoxy in tension

Meshing structures

Applications of HLPMHigh strain rate loading:

Thermally induced fracture:

(a) Temperature (b) Fracture

Mixture of calcite and pyrite subject to a microwave

Blasting:

Crack propagation:

Spallation of plate impact:

Wave propagation:

3-D puncture and shock fracture:

AcknowledgementNSERC, COREM (Canada), SERRI, ONR (USA)

Material subject to heating:

Random meshing

(b) Indentation of polymeric materials

Load Energy

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Ge Wang’s other computational materials science related research work (gewang0419@gmail.com)

Projectile penetration of material Helmet impact

Bird impact on airplane wing Explosive in urban area

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HLPM Publications on Journals G. Wang, A. Al-Ostaz and A.H.-D. Cheng, (2011), Hybrid lattice particle modeling of retrofitting infrastructure

design under a blasting load, Journal of Nanomechanics and Micromechanics (revised) G. Wang, A.H.-D. Cheng, M. Ostoja-Starzewski, A. Al-Ostaz, and, P. Radziszewski (2010), Hybrid lattice particle

modeling Approach for Polymeric Materials Subject to High Strain Rate Loads, review paper invited to Polymers, 2, 3-30.

G. Wang, A. Al-Ostaz, A.H.-D. Cheng and P. Radziszewski (2009), Particle modeling and its current success in the simulations of dynamic fragmentation of solids, Strength of Materials (Edited By Gustavo Mendes and Bruno Lago), Nova Science Publishers, ISBN: 978-60741-500-8, chapter 5, 157-182.

G. Wang, A. Al-Ostaz, A.H.-D. Cheng and P.R. Mantena (2009), Hybrid lattice particle modeling of wave propagation induced fracture of solids, Computer Methods in Applied Mechanics and Engineering, 199, 197–209.

G. Wang, A. Al-Ostaz, A.H.-D. Cheng and P.R. Mantena (2009), A macroscopic-level hybrid lattice particle modeling of Mode-I crack propagation in inelastic materials with varying ductility, International Journal of Solids and Structures, 46, 4054-4063.

G. Wang (2009), Particle modeling of polymeric material indentation study, Engineering Fracture Mechanics, 76, 1386-1395.

G. Wang, A. Al-Ostaz, A.H.-D. Cheng and P.R. Mantena (2009), Hybrid lattice particle modeling: theoretical considerations for a 2-D elastic spring network for dynamic fracture simulations, Computational Materials Science, 44, 1126-1134.

G. Wang, A. Al-Ostaz, A.H.-D. Cheng and P.R. Mantena (2008), Particle Modeling of a Polymeric material (nylon-6, 6) due to the Impact of a Rigid indenter, Computational Materials Science, 44, 449-463.

G. Wang, P. Radziszewski and J. Ouellet (2008), Particle modeling simulation of thermal effects on ore breakage, Computational Materials Science, 43, 892-901.

M. Ostoja-Starzewski, G. Wang (2006), Particle Modeling of Random Crack Patterns in Epoxy Plates, Probabilistic Engineering Mechanics, 21, 267-275.

G. Wang, M. Ostoja-Starzewski, P. Radziszewski and M. Ourriban (2006), Particle modeling of dynamic fragmentation – II: fracture in single- and multi-phase materials, Computational Materials Science, 35, 116-133.

G. Wang, M. Ostoja-Starzewski (2005), Particle modeling of dynamic fragmentation – I: theoretical considerations, Computational Materials Science, 33, 429-442.

Contact address: gewang0419@gmail.com

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Ge Wang’s CFD and FSI related research work (gewang0419@gmail.com)

Atmospheric flow over a regional complex terrain and plume

dispersionA 3D time-dependent mesoscale meteorological model, HOTMAC (Higher Order Turbulence Model for Atmospheric Circulations), is applied to study the complex terrain airshed. The outputs from HOTMAC are used as inputs for the ‘puff dispersion’ model, RAPTAD (Random Particle Transport And Diffusion), to capture details of the pollutant motions.

Oscillatory flow

Cavitating flow

2D shallow water equations are employed.

AcknowledgementSERRI, SCERP, US Navy

Velocity vectors Spatial plume trajectory

A single fluid model of density-based sheet/cloud cavitation scheme is developed and incorporated into a weakly-compressible 3D FVM LES Navier-Stokes equations.

Sheet cavitation Cloud cavitation

2D FEM-FDM LES technique is developed.

Terrain

Flood inundation due to dam and levee breach

Prediction

Scoring and erosion of the foundation soils

Fluid-structure interaction

Material erosion due to cavitating flow

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CFD related Publications on Journals C.R. Song, J. Kim, G. Wang and A.H.-D. Cheng (2009), Reducing Erodibility of Soils

Using Engineered Flood Wall Sections, ASCE International of Geomechanics (In press). G. Wang, M. Ostoja-Starzewski (2007), Large eddy simulation approach of sheet/cloud

cavitation on a NACA0015, Applied Mathematical Modeling, 31, 417-447. G. Wang, M. Ostoja-Starzewski (2006), Meteorological simulations of atmospheric

flow and tracer transport in Phoenix, Arizona, Meteorological Applications, 13, 235-241.

G. Wang, M. Ostoja-Starzewski (2004), Influence of topography on the Phoenix CO2 dome: a computational study, Atmospheric Science Letters, 5, 103-107.

G. Wang, M. Ostoja-Starzewski (2004), A numerical study of plume dispersion motivated by a mesoscale atmospheric flow over a complex terrain, Applied Mathematical Modeling, 28, 957-981.

M.J. Brown, C. Muller, G. Wang and K. Costigan (2001), Meteorological simulations of boundary-layer structure during the 1996 Paso del Norte ozone study, The Science of the Total Environment, 276, (1-3), 111-133.

Y.C. Li, B. Chen and G. Wang (1996), Physical model test and numerical simulation of pipeline under wave action, Chinese Marine Science Bulletin, 4, 58-65.

G. Wang, Y.C. Li and G.Z. Lai (1994), FDM-FEM approach for numerical simulations of a circular cylinder in oscillatory plus constant flow coming from arbitrary directions, J. of Hydrodynamics (in Chinese), Ser. A Vol. 9, No. 2., 224-233.

Contact address: gewang0419@gmail.com