Failure Analysis On Thermal Shock

This dissertation includes three parts. In the first part, the line spring model(LSM) considering arbitrary distrib ted loads on crack surfaces and the corresponding constitutive relations are proposed. It is used to analyze a surface-cracked plate subjected to thermal shock. The mathematical formulation for this problem is reduced finally to two-coupled integral equations. The model is also installed into ADINA code as an additional element to analyze surface cracks in cylindrical shells under thermal loading conditions. The behavior of an inner-surface crack in pressure vessels subjected to thermal shock is investigated.The second part of this dissertation presents the analyses for Warm Prestressing (WPS). Chell's theory is re-examined and it is found that the J(?) defined by Chell should be reformulated. As a new control parameter, the integral Jwis proposed to explain the WPS phenomenon. By comparison with published WPS data, Jwintegral is more available.In the third part of this dissertation, the temperature field near the crack tip due to irreversible energy dissipation are studied within the framework of thermodynamics including internal variable descriptions. For Mode III stationary crack, the temperature elevations in the plastic zone of a crack are calculated in elastic perfectly-plastic and power hardening materials. For Mode I stationary crack, the temperature distribution considering damage effect is carried out.