CSAR Seminar

SPEAKER: Renfu Li, Millennium Dynamics Co., Atlanta

TITLE: Simulation of Lamb Wave Propagation in Structures with Damage by Parallel Hybrid FD and Singular FE Method

DATE: Wednesday, September 27, 2006
TIME: 12:00 Noon
PLACE: 2240 DCL
1304 W. Springfield Ave., Urbana, IL

ABSTRACT

The simulation of wave propagation in bounded plate-like structures with damage is investigated by a parallel hybrid finite difference (FD) and singular finite element (FE) approach. The geometric scales of the plate are considered to have finite thickness in one direction, (z) and bounded length in the other two directions, (x, y). The conditions for the separation forms to the displacements induced by the wave motion are derived, reducing the 3D problems to 2D ones. Then a combination of 2D FDM and 2D FEM is employed: the FD scheme is used to find the solution in the body as a whole, while singular FE is used to advance the field variables around the crack tip. The whole computational domain is partitioned into N blocks and assigned to N processes: one process is responsible for the computation of singular finite element, the other processes are responsible for computations of the finite difference method. The procedure can improve the efficiency of the computation and avoid computing the derivative across a singularity around the crack tip. The method was implemented using C++ and MPI.

Dr. Li will also discuss some of his other work, such as a unified dislocation-based approach to solve thermal interface crack/delamination and its branching problem in dissimilar anisotropic conventional/smart bi-materials, modeling face-core de-bonding by cohesive elements, spectral element method for damage detection, and non-local continuum elastic shell models for nano-composites.

BIOGRAPHY

Dr. Li graduated with his Ph.D. degree from the school of Aerospace Engineering of the Georgia Institute of Technology in December of 2004. In his Ph.D. thesis, Dr. Li addressed the interface thermal-mechanical failure modes for dissimilar anisotropic bimaterial media based on dislocation theory and complex analysis. After his graduation, Dr. Li worked as a post-doctoral fellow at Georgia Tech for one year, and is now a research scientist and project director at the center for aerospace structural health monitoring of Millennium Dynamics Co. in Atlanta, Georgia. Dr. Li also holds M.S. degrees in Mathematics and in Computer Science. His research interests include fracture/damage mechanics, structural dynamics, nano-mechanics, structural health monitoring, and computational mechanics. He has reviewed more than 20 papers for journals such as Journal of Applied Mechanics, International Journal of Non-linear Mechanics, International Journal of Nano-mechanics, International Journal of Solids and Structures, etc. Georgia Tech honored him with the Luther Long Award in 2005.