International collaboration within the project:

1. Materials World Network:Multi-Scale Study of Chemical Vapor Infiltrated Carbon/Carbon CompositesIgor Tsukrov, University of New Hampshire,DMR-Award 0806906 Chemical vapor infiltrated carbon/carbon composites have a complex hierarchical microstructure that has to be considered on submicron (nanotextured pyrolytic carbon, PyC), micro (transversely isotropic infiltrated fiber bundles) and meso (porous fiber-PyC system) length scales. One of this year’s thrusts has been on characterization and modeling of porosity in the composite. Due to highly irregular pore shapes, conventional micromechanical models based on Eshelby solution for ellipsoidal defects have limited applicability for porous carbon/carbon composites manufactured by chemical vapor infiltration. Recent paper submitted by the project team reports the accuracy of conventional approaches to be within 20% of exact models. A methodology combining transmission electron microscopy (to characterize PyC texture) and X-ray computed microtomography (to determine the morphology of porous space) with advanced micromechanical modeling techniques is developed to evaluate contribution of pores of irregular shapes to the overall mechanical properties of carbon/carbon composites. Porosity in carbon/carbon composites is characterized by X-ray computed microtomography and modeled by a combination of finite element analysis and micromechanical methods

2. Materials World Network:Multi-Scale Study of Chemical Vapor Infiltrated Carbon/Carbon CompositesIgor Tsukrov, University of New Hampshire,DMR-Award 0806906 a b This Materials World Network project involves intensive collaboration and student exchange between the University of New Hampshire (UNH, USA) and Karlsruhe Institute of Technology (KIT, Germany). During the last year, the project team organized a minisymposium at the IV European Congress on Computational Mechanics in Paris, a special session at the 81st Annual Meeting of the International Association of Applied Mathematics and Mechanics in Karlsruhe, Germany, and presented their results at six international conferences. Two project meetings were held: in the US (2009) and in Germany (2010). Two American graduate students participated in the research program at KIT, and one German student conducted his Diploma research at UNH. c • International collaboration within the project: • (a) A visiting student from Germany, M. Buck, helps perform nano- • indentation measurements at the UNH AFM Laboratory;(b) N. Timoshchuk (UNH) and Dr. Reznik(KIT) performing micro- • indentation at KIT, Germany; • American and German teams during the project meeting in USA