Highsmith dissertation defense
The document summarizes Shelby Highsmith's doctoral thesis defense on crack path determination for non-proportional mixed-mode fatigue. The project objectives were to assess and validate models of crack path selection under complex mixed-mode loading and contribute to material databases. Early models predicted crack trajectory based on stress or strain energy criteria. Under non-proportional loads, crack path is difficult to predict as load mixity changes. Experiments on Inconel 718 specimens under various proportional and non-proportional load cases aimed to enhance understanding of modal transitions and crack path behavior. Results from in-phase tests showed crack deflection followed expected criteria and transitioned as load mixity increased.
