Michigan Technological University
Department of Physics

is pleased to announce a colloquium

with

Xin-Lin Gao

Micromechanical Modeling of Graphitic Carbon Foams

Microcellular graphitic carbon foams first developed at the Air Force Research Laboratory (AFRL) in the 1990s are rapidly emerging as a new class of ultra-light cellular materials for structural and thermal management applications because of their excellent physical properties. These 3-D open-cell carbon foams, like other cellular solids, are topology-sensitive and, therefore, their physics-based modeling requires the incorporation of microstructural features of cells.

AFRL graphitic carbon foams are blown from anisotropic pitch through a bubble forming process, and, as a result, microstructures of the solidified carbon foams are controlled by the principle of minimum surface energy. As a first approximation, a regular tetrakaidecahedron containing 36 struts and 24 vertices can be adopted as a repeating unit to represent the 3-D open-cell foam microstructure. Tetrakaidecahedron is known to be the only polyhedron that can pack with identical units to fill space and nearly minimize the surface energy.

In this talk, two micromechanical models recently developed at MTU for 3-D open-cell foams utilizing tetrakaidecahedral unit cells will be discussed. One model is based on Castigliano’s second theorem, and the other is developed using the matrix method for space frames. The former provides closed-form formulas, while the latter furnishes a computerized procedure.

Biography

Xin-Lin Gao is an Assistant Professor in the ME-EM Department, MTU. He received his M.Sc. degree in Engineering Mechanics in May 1997, and a Ph.D. degree in Mechanical Engineering in May 1998, both from the University of Wisconsin-Madison. He is the author of 37 journal papers and over 20 conference publications. The journals that have published his papers include Int. J. Solids Struct., ASME J. Appl. Mech., Z. angew. Math. Phys., IMA J. Appl. Math., Math. Mech. Solids, Mech. Res. Comm., Int. J. Pres. Ves. Piping, and Compos. Sci. Tech.. The subjects covered in his publications include elasticity, plasticity, applied mathematics, icromechanics, composites, mechanics of nanotubes, failure mechanics, and thermodynamics. His current work on micro/nano-mechanics and nanostructured materials is being funded by NSF and AFOSR.

Thursday, September 25, 2003

4:00 p.m., Fisher 139

Refreshments will be served

MTU | Physics | Colloquium