Computational Physics GroupKarel Matous 


Cohesive Modeling of Dewetting in Particulate Composites: Micromechanics vs. Multiscale Finite Element AnalysisH.M Inglis^{1}, P.H. Geubelle^{2}, K. Matous^{2,3}, H. Tan^{1} and Y. Huang^{1} ^{1}Department of Mechanical Engineering ^{2}Department of Aerospace Engineering ^{3}Center for Simulation of Advanced Rockets University of Illinois at UrbanaChampaign Urbana, IL 61801, USA. Abstract
Conclusions
the effect of dissimilar particle sizes. The 2D micromechanics model developed by Tan et al. (2005a) is effective at capturing key features of the macroscopic stressstrain response for minimal computational effort. The shortcomings of this model are that it cannot capture the instability inherent in the system or the heterogeneous stress and strain fields. In a highly filled composite, interactions between particles are a significant contributor to failure through local stress concentrations and the occurrence of localization. The micromechanics model does not capture these interactions during the failure process, and hence ceases to be predictive under high volume fraction, f > 0:5, when stress concentrations begin to play a significant role in the solution, or when the particle distribution is random, resulting in localization. Both models demonstrate that, for large differences in particle diameters, it is unnecessary to model the debonding of smaller particles, but is sufficient to represent their contribution to damage nucleation and to the stiffness of the matrix. The ability of the MTHFE code to function as a direct numerical simulation for validation of simpler models has been demonstrated. The MTHbased code has an ability to capture a richness of detail about the physical response of the system. The method is capable of solving more complex loading cases, and can be extended to include different material models. AcknowledgmentThis work was supported by the Center for Simulation of Advanced Rockets (CSAR) under contract number B341494 by the U.S. Department of Energy. K. Matous and P. H. Geubelle also acknowledge support from ATK/Thiokol (Program Managers, J. Thompson and Dr. I. L. Davis). H. Tan and Y. Huang acknowledge additional support from ONR Composites for Marine Structures Program (Grant N000140110205, Program Manager Dr. Y.D.S. Rajapakse). © 2009 Notre Dame and Dr.
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