A Computational-Experimental Program for Multiple Scale Modeling of Failure in Non Uniform Composite Materials
Sponsor: : Air Force Office of Scientific Research
PI: S. Ghosh
Keywords: Multi-Scale Analysis, Damage Evolution, Interfacial Debonding, VCFEM
Abstract:
This is a research program on ` A Computational-Experimental Approach to Hierarchical Modeling of Damage and Failure in Non-Uniform Composite Materials’ at the Ohio State University, for which S. Ghosh is the principal investigator. The research has developed an integrated computational experimental research program aimed at improving reliability and performance of composite structures. This is accomplished by advancing a system of adaptive multiple scale computational models and codes for modeling fiber reinforced organic matrix composite components, with emphasis on predict failure as a consequence of evolving microstructural damage. The program complemented ongoing research thrusts in composite failure at AFRL Materials Directorate, under the direction of N. J. Pagano. Partnership with Ohio Super-Computer Center (OSC) imparted comprehension needed for analysis and design of commercial composites and introduce state of the art techniques of high performance computing for optimal performance. Various developmental modules are:
• The Computational Module
· An Adaptive Multi-level Computational Model: to concurrently predict variables at the micro-, meso- and macro-scales, and model the composite failure process as a phenomenon of incidence, interaction and propagation of microstructural cracks. Adaptivity created a hierarchy of computational sub-domains that will impart preferential resolution and zoom in at `damage hotspots' for microscopic simulations. Both the macroscopic and microscopic modules are equipped with modeling and numerical error-based adaptivity, for optimal efficiency and accuracy. Pollution and local error measures, together with hp-adaptivity have been implemented for solutions with high gradients.
· The Voronoi Cell FE Model (VCFEM) for Microstructural Damage Evolution: has been developed, based on actual microstructural morphology of organic matrix composites and will account for precise microstructural geometry and interactions. The present Voronoi cell element formulations of damage by fiber cracking and fiber-matrix interfacial decohesion, will be advanced to model initiation, growth and link-up of matrix cracking. Cohesive zone models, in terms of interfacial tractions and separation, will be used in this formulation. VCFEM has been augmented with adaptive stress and displacement enhancements to improve accuracy in regions of intense damage.
· Parallelization of Codes for High Performance Computing: has been achieved. Novel paradigms with emphasis on optimal load balancing strategies and scalable parallel I/O schemes have been developed.
• The Experimental Module
· Mechanical Tests with Fiber Reinforced Organic Matrix Composite Systems: Laboratory scale mechanical tests will be performed with commercial and model composite systems to aid in the development of the computational models. The tests will investigate the effects of microstructure on stress-strain and damage response.
In summary, the research has blended novel computational and experimental methods to advance the state of the art in complex failure modeling that govern reliable analysis and design methodology of composite materials and structures. This program has followed the directives of the Air Force's Affordable Composites Initiative, for large unitized and shape controlled composite structures.
OSU Research Team
Professor: S. GhoshGraduate Student: P. Raghavan, S. Li, S. Swaminathan and Y. Ling