Micromechanical characterization of cyclic plasticity of IM7/5260 composite at various temperatures

摘要

Uniaxial cyclic tests were performed on composite IM7/5260 and matrix Narmco 5260 specimens at 24 degrees C (75 degrees F), 107 degrees C (225 degrees F) and 149 degrees C (300 degrees F). Based on the test results, a constitutive model was obtained to describe matrix cyclic plasticity. Subsequently, by assuming linear elastic behavior for fiber IM7 and perfect bonding between fiber and matrix, a simple micromechanical model was used to predict the cyclic behavior of the composite. For initial loading, model predictions agree with experimental results very well. For the subsequent cyclic loading, the model underestimates the average stiffness over a cycle, and the matrix properties require adjustments to yield satisfactory results. [References: 12]