EVALUATION OF CREEP-FATIGUE DESIGN METHODS BY STRUCTURAL FAILURE TESTS UNDER THERMAL LOADS

Creep-fatigue tests were conducted under cyclic thermal stresses using two types of simple structural models, the free surface model and rin g cylinder model. All models were made of SUS304 stainless steel and s ome of the specimens had longitudinal welds. Failure lives were define d as the cycle at which small visible cracks were detected. Three kind s of life evaluations were made. Two of these were based on elastic an alysis and one of these was based on inelastic analysis. The estimated lives were compared with the experimental results and the results can be summarized as follows. (1) Life estimation based on inelastic anal ysis was adequate and the estimated lives agreed well with the experim ental results. (2) Life estimation by the Monju Design Guide based on elastic analysis gave conservative results, However, the accuracy of l ife estimation could be improved by using the elastic follow-up factor (q value) obtained from inelastic analysis.