Mechanical Engineering ETDs

Publication Date



The general interests of engineers in fracture mechanics are oriented through their interest in the structural strength. The studies branched into two major areas in fracture theory, namely the initiation problem and the stability problem. Although some of the initiation problems could be approached through the existing failure theories, other aspects are still active research subjects, such as the statistical theory of fracture. In the stability problem, we are faced with a situation in which the adverse condition already exists because cracks are present. Whether the presence of the crack under the loading condition is insignificant or critical is the realm of interest in the stability analysis of fracture mechanics. The classical theory of Griffith [1, 2] could yield general guideline for fracture stability, but failed to prescribe a definite configuration of fracture. Such configuration, at the macroscopic level in a homogeneous material, is more or less determined by the local strain field in the neighborhood of a crack-tip [3]. Numerous efforts were directed toward obtaining the strain field measurement in that region both analytically and experimentally. A few successful experimental measurements all indicated a large plastic region which could not be correlated to the few analytical solutions which were based on the elastic fracture concept. The difficulty came about because, when low-ductility materials were used, the crackings were invariably in the 'catastrophic' manner. Immediate consequences were that it was difficult to measure the strain field and that even when the measurement had been possible, the deviation of the measurement from the critical state could not have been evaluated.

Degree Name

Mechanical Engineering

Level of Degree


Department Name

Mechanical Engineering

First Committee Member (Chair)

Frederick Dsuin Ju

Second Committee Member

Richard Charles Dove

Third Committee Member

James Tsu-Ping Yao

Document Type