Deformation and fatigue of a particulate-reinforced metal matrix composite

The goals set forth in this research were to theoretically and experimentally investigate the deformation and fatigue of a particulate reinforced metal matrix composite subjected to axial, torsional and combined axial/torsional loadings.; An elastic-plastic, composite constitutive model was formulated and implemented for this research. This constitutive model was based on Eshelby's equivalent inclusion method, Mori and Tanaka's mean field theory and Li and Chen's incremental elastic-plastic formulation. The Fatemi-Kurath shear-based critical plane fatigue damage parameter and the Smith-Watson-Topper tensile-based critical plane fatigue damage parameter were implemented in an attempt to correlate the fatigue life data obtained for the composite material for the three loading cases tested in this research. Fatigue life calculations were also performed by relating these damage parameters to the fatigue life using uniaxial fatigue life parameters. For the purposes of this research, fatigue life was defined as complete specimen fracture for ail loading cases and specimen types tested.; A series of monotonic and fully-reversed cyclic uniaxial tests and fully-reversed cyclic torsional and combined axial/torsional tests were performed on an aluminum-based particulate reinforced metal matrix composite material. The monotonic elastic properties predicted by the model agreed quite well with the average experimental properties for the composite material. The tensile properties obtained from the simulated monotonic stress/strain curves agreed quite well with the average experimental properties for the composite material. Overall, the composite constitutive model used in this research simulated the cyclic stabilized response of the 6061/{dollar}rm Alsb2Osb3{dollar}/20p-T6 material fairly well for all loading cases.; The Fatemi-Kurath damage parameter (with k = 1), collapsed the experimental fatigue data of the 6061/{dollar}rm Alsb2Osb3{dollar}/20p-T6 material from all loading cases reasonably well. The SWT damage parameter did not collapse the data as well as the Fatemi-Kurath parameter. Using uniaxial strain-life parameters, both damage parameters produced fairly reasonable fatigue life calculations for the shorter fatigue lives, while producing increasingly conservative results for the longer fatigue lives.