Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical Engineering


The Bodner-Partom model of nonlinear time-dependent material behavior was incorporated into a finite element code to predict the strain response at the notch root of an Inconel 718 specimen subjected to cyclic tension-compression at 649(DEGREES)C. A numerical minimization technique was developed to establish the parameters in the Bodner-Partom model. This technique was applied to creep and stress strain data obtained from button-head test specimens tested at 649(DEGREES)C. These parameters were found to be in general close agreement with those obtained by other investigators. The test specimen for the experimental phase of this research was double notched with an elastic stress concentration factor of 1.94. It was subjected to cyclic plastic loads at 649(DEGREES)C which were large enough to generate plastic deformation at the notch root on the tensile portion of the cycle. This behavior was then predicted by incorporating the Bodner-Partom model into a finite element code. The predicted strain response and the experimentally measured (using a laser-based technique) strain response agreed reasonably well.