fatigue analysis of structures requires nowadays specific numerical tools able to take account of complex multiaxial loadings generated by the use of fem structural calculations. traditionally fatigue is studied in different ways depending on the fatigue regime and the field of interest: fatigue limit analysis, life prediction in high or low cycle fatigue, thermal fatigue？ the application of the shakedown theory to the analysis of the fatigue problems permits to present a unified theoretical background to both high and low cycle fatigue. this point of view allows interpreting all types of industrial problems of fatigue in an efficient manner. the description of the stabilised mechanical state after shakedown at macroscopic and mesoscopic scales gives access to engineering values which will drive the fatigue damage of the structure. the formulations are intrinsic and suffer no ambiguities. some examples of fatigue analysis for different industrial areas are presented.