MICRO/MACRO MECHANICS FOR COMPOSITE FRACTURE CRITERIA

ALTHOUGH STRONG IN THE LAMINATE PLANE, COMPOSITES EXHIBIT WEAK INTERLAMINAR PROPERTIES. AS A RESULT, DELAMINATIONS CAN OCCUR DURING MANUFACTURING OR IN SERVICE ENVIRONMENTS. THIS PROPOSAL ADDRESSES A NEED FOR FRACTURE CRITERIA MODELS FOR BOTH ORGANIC AND METAL MATRIX COMPOSITES. A MAJOR OBJECTIVE IS TO ANALYZE AND COMPARE FRACTURES IN MICROSCOPIC AND MACROSCOPIC GEOMETRIES USING A SINGULAR FINITE ELEMENT METHOD. THE RESULTS OF THIS ANALYSIS WILL BE USED TO DEVELOP A MIXED-MODE, MACROSCOPIC FRACTURE CRITERIA ANALYTICAL MODEL THAT INCORPORATES MICROSCOPIC TOUGHENING MECHANISMS.