A Stress Gradient Failure Theory for Textile Structural Composites
Final technical rept. 1 Sep 2002-31 Aug 2005
FLORIDA UNIV GAINESVILLE MECHANICAL AND AEROSPACE ENGINEERING
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Micromechanical methods for stiffness and strength prediction are presented, the results of which have led to an effective failure theory for prediction of strength. Methods to account for analysis of multi-layer textile composites are also developed. This allows simulation of a single representative volume element RVE to be applicable to a layup of an arbitrary number of layers, eliminating the need for further material characterization. Thus a practical tool for failure analysis and design of a plain weave textile composite has been developed. These methods are then readily adaptable to any textile microarchitecture of interest. A micromechanical analysis of the RVE of a plain-weave textile composite has been performed using the finite element method. Stress gradient effects are investigated, and it is assumed that the stress state is not uniform across the RVE. This is unlike most models, which start with the premise that an RVE is subjected to a uniform stress or strain. For textile geometries, non-uniform stress considerations are important, as the size of a textile RVE will typically be several orders of magnitude larger than that of a unidirectional RVE.