First, it is pointed out that the damage law of evolution for high cycle fatigue advanced by Lemaitre is only applied to the loading of equal amplitudes on equivalent stress cycles.

Based on the modified Miner linear accumulative damage theory and S-N curve of drill sting,two parameters of fatigue damage in one stress cycle and fatigue accumulative damage strength of drill sting were defined.

A study of ratchetting behaviour under proportional and nonproportional cyclic stressing;

The ratcheting and low-cycle fatigue (LCF) properties of the material were investigated in uniaxial cyclic stressing.

Experimental study on shearing deformation behavior of saturated clay under cyclic stress;

The cyclic stress?strain curves of ZA27 alloy with different treatment have been obtained in constant strain amplitude condition and the corresponding microstructure,the fractograyh obtained under different treatment condition are presented.

The cyclic stress strain properties of ZA27 alloy and ZCuSn10P1 at ambient temperature were studied in this paper The cyclic stress strain curves of them are obtainaed The results show alloy ZA27displayed the cyclic softing character.

Bolted flanged connections are liable to failure, which work for a long time under the operating conditions that pressure and temperature change frequently By means of the application of the constitutive equation of gaskets to the load deformation equation of bolted flanged connections, a method to calculate the cyclical stress of bolts is put forward when the pre tightening conditions are know

By fixing the maximum values of tensile stress in all tests but changing the minimum values of tensile stress in various tests, the effect of cyclic stress amplitude or mean stress and their interaction on the damage of materials may be differentiated.