In view of the materials fatigue life prediction problem under step blocks specturm

especially the calculation parameters of the existing nonlinear models depend on a large number of test data or it is difficult to select a suitable reference value

which leads to the limitation in practical engineering application.A new effect coefficient αi=(Si+1/Si)1/b lg K based on adjacent load was proposed

in which the two parameters b

K were derived from the fatigue life relation S=KN-b.The fatigue damage models and the results which combined with the previous experimental results of two-

three-and four-stage loading were calculated and compared.The results show that the new model has better fatigue life/damage predicted results than Miner model

Manson model

Subramanyan model and Hashin model

which can be predicted more accurately in fatigue life/damage under step blocks spectrum.