An Integrated Approach To Creep Fatigue Life Prediction PDF Download

There has been special interest recently in developing new, reliable analytical design methods for components under higher temperature conditions. However, at present, the use of material properties is still limited to arrays of single characteristics which do not interact with each other. In this work, several creep fatigue experiments on smooth specimens of IN 800 H have been carried out at 830°C. In some tests, these have also been combined with inside hysteresis loops to investigate the different effects on deformation and damage behavior which originate in a creep and fatigue environment. As a result of these tests, it has been found that the material behavior under creep-fatigue conditions can be significantly changed compared to the material behavior under simple load conditions. Therefore there is a need for life analysis methods to be expanded to include possible variations in properties; for greater accuracy, the material properties must be treated as a complex interacting system of parameters. The examination has been extended to a typical component used under high-temperature conditions. The results of the numerical analysis show that the stress-strain history in the critical area of that component is not simply strain controlled, as it is in the typical laboratory creep-fatigue interaction life test containing a tensile or compressive dwell at constant peak strain level. At high temperatures, the conditions in the component are more severe, causing the life to be reduced compared with the typical laboratory test. In this paper, these conditions are successfully simulated with the help of a generalized Neuber law: ? . ?p = constant. Based on this ratio, the engineering method for evaluating component geometry and loading conditions and their effects on material behavior can be established.