A NEW HIGH-TEMPERATURE CREEP-FATIGUE DAMAGE RULE-BASED ON THE STRAIN RANGE PARTITIONING CONCEPT

A new life prediction model based on the strain range partitioned crac k growth rate equations is presented which can evaluate the material d amage and the residual life under variable creep-fatigue strainings. T wo-step sequential creep-fatigue straining tests such as High-Low and Low-High tests were conducted on Mod. 9Cr-1Mo steel and type 316LC sta inless steel in order to examine the validity of the proposed model. I t was found that the proposed model can be more successfully applied t o the creep-fatigue life prediction under variable strainings than the conventional life prediction methods.