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Progressive Failure Analysis of a Stack of Aligned Prepreg Platelets



A computational, three-dimensional model for simulation of progressive failure in a stack of aligned prepeg platelets was developed. The model was based on a representative volume element (RVE). Two possible failure mechanisms were considered for the platelet stack: (i) the failure of platelets and (ii) the dis-bonding between platelets. Continuum and discrete damage mechanics models were used to represent the constitutive behavior of RVE elements during the progressive failure of a stack. Direct coupling of the two failure models was accomplished by incorporating both damage models within a single finite element model. A numerical study was conducted to investigate the effect of platelet geometry and stack topology on the macroscopic failure response of the platelet-stacked, composite system. Increased platelet length-to-thickness ratio and platelet overlap length were found to improve the homogenized tensile strength of a stack. Enhanced stress sharing between platelets was shown to be responsible for stack strength improvements. In such a case, the platelet stack failure was governed by the platelet fracture rather than platelet disbonding. Critical platelet aspect ratio and overlap length ratio were determined from the analysis.

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