1986 Volume 29 Issue 258 Pages 3986-3992
A series of creep-fatigue interaction tests were conducted in order to evaluate a criterion for failure taking into account the detrimental effect caused by the time dependent process. From the test data on commonly used high temperature materials for gas turbine and diesel engine in air, hydrogen gas and corrosive ash, we proposed a life estimation method under the combined creep-fatigue loadings. This method based on linear cummulative creep damage expressed by the equivalent hold time is stress dependent and independent of loading modes. We confirm by this method that the correlation between experimental data or available data in literatures and estimation is quite good for several types of loadings. Our experiments need no complicate testing to obtaining the material constants but require only the conventional simple low cycle fatigue tests with the effects of hole time considered at peak strain or stress and creep rupture tests.