Creep-fatigue maps from multistage life prediction methods

The derivation of creep-fatigue maps can represent an useful application of multistage life prediction models. Computations directly provide, in suitable two-dimensional diagrams, the demarcation lines among zones where survival, rupture by static or cyclic creep, fatigue, and creep-fatigue interaction prevail. Moreover, inside some of the mentioned zones, lines can be defined for constant amounts of fatigue damage, or of creep life and/or fatigue cycles. The maps here discussed are based on load parameters and are usually drawn as a function of the frequency of the applied load. Both the mean applied load and the amplitude of the oscillation have been used as fundamental variables. The reported maps, beside offering a general overview of the material behaviour, provide an useful tool for increasing the agreement of the model with the experimental data in a very large range of load conditions.