Seminar Series - 2003-2004

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

Somnath Ghosh
Professor of Mechanical Engineering and Materials Science & Engineering
The Ohio State University, Columbus, OH 43210
ghosh.5@osu.edu

Date:  Tuesday, November 11, 2003
Time:  3:00 p.m.
Place:  105 Othmer Hall



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.

Professor Somnath Ghosh’s research is in the field of computational mechanics for modeling of materials and manufacturing processes. He has made contributions to the field of computational-experimental modeling of heterogeneous materials like composites, porous, polycrystalline, and bio-material materials through the integrated use of quantitative metallography, microstructural characterization, microstructural modeling and adaptive multiple scale modeling. For image-based microstructural modeling, he has developed the Voronoi Cell Finite Element Method for efficient and accurate modeling. Professor Ghosh was a recipient of the NSF National Young Investigator (NYI) Award, the Harrison Faculty Award for Excellence in Engineering Education and three times the Lumley research award for outstanding research at the Ohio State University. He is a fellow of the American Society for Mechanical Engineers. He is a member of the executive council of US Association for Computational Mechanics.

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