CSE Symposium Keynote

Prof. Somnath Ghosh, Ohio State University

TITLE: Multi-Level Computational Models For Multiple Scale Analysis of Composite Materials

DATE: Friday, April 25, 2003
TIME: 9:00 A.M.
PLACE: 1005 Beckman Institute

ABSTRACT

In this work, a multiple scale computational model is developed to concurrently predict evolution of variables at the structural and microstructural scales, as well as to track the incidence and propagation of microstructural damage. The microscopic analysis is conducted with the Voronoi cell finite element model (VCFEM) while a conventional displacement based FEM code executes the macroscopic analysis.

Adaptive schemes and mesh refinement strategies are developed to create a hierarchy of computational sub-domains with varying resolution. Such hierarchy allow for differentiation between non-critical and critical regions, and help in increasing the efficiency of computations through preferential `zoom in' regions. Coupling between the scales for regions with periodic microstructure is accomplished through asymptotic homogenization, whereas regions of nonuniformity and non-periodicity are modeled by true microstructural analysis with VCFEM.

An adaptive Voronoi cell finite element model is also developed for micromechanical analysis. Microstructural damage initiation and propagation in the form of debonding and particle cracking are incorporated. Error measures, viz. a traction reciprocity error and an error in the kinematic relation, are formulated as indicators of the quality of VCFEM solutions. Based on a-posteriori evaluation of these error measures, element adaptation is executed by displacement function adaptations and enrichment of stress functions. The complete process improves convergence characteristics of the VCFEM solution. Aspects of parallel computing in the implementation of the codes will be discussed.

BIOGRAPHY

Dr. Ghosh's research focuses on the development of new frontiers in Computational Mechanics applied to the fields of material modeling, manufacturing, design and biological materials. His research group has developing integrated computational models for linking material characterization, multiple scale modeling, optimal design and processing of advanced materials. A major focus is on failure analysis and reliability of materials. Multi-scale simulation of manufacturing processes and design of processing conditions as well as design of biological implants are also an active research areas in his group. Dr. Ghosh and his students have developed the powerful Voronoi Cell Finite Element Method (VCFEM), which has gained international recognition. He has also contributed to the area of computational modeling of metal forming and casting processes. He is one of the first contributors in Arbitrary Lagrangian-Eulerian Finite Element Method for metal forming and casting analysis. He has also worked on optimal design of metal forming problems using Genetic Algorithms.

Prof. Ghosh is a Fellow of the American Society of Mechanical Engineers and is the Chairman of the Committee of Materials Modeling of the United States Association of Computational Mechanics. He received the National Science Foundation's prestigious Young Investigator Award in 1994. He received the Harrison faculty award for Excellence in Engineering Education in 2001 and the Lumley Research award in 1998 and 1994 from the OSU College of Engineering