MICROMECHANICS OF COMPOSITE-MATERIALS UNDER COMPRESSIVE LOADING

A common thread joining many engineered materials used dominantly unde r compressive loading is the presence of a high modulus secondary phas e, either fiber or particulate, embedded within a lower modulus matrix phase. To improve their toughness, a frictional or a less-than-cohere nt interface is strived for in the manufacture of these composite mate rials. To form a better understanding of the complex behavior of these materials, numerical and experimental models were developed by the U. S. Bureau of Mines that allowed a wide range of micromechanical and fr acture behavior to be investigated under compressive loading. Finite e lement modeling illustrates the effects of interfacial friction and el astic moduli mismatch between the reinforcement and the matrix. Additi onal results show that packing density or non-dilute concentration of reinforcements have little effect upon the micromechanical behavior un der uniaxial compressive loading. These numerical results were then su bstantiated:by crack initiation experiments on model composite materia ls.