Research On Fatigue Cycle Counting Method And Life Prediction Under Multiaxial Random Loading

The majority of the loading acted on the components of engineering structure in service ismultiaxial, even random loading. Although there have got some progress in domestic and internationalresearch on multiaxial fatigue. But multiaxial fatigue damage mechanism is very complex. Thefatigue life is affected by many factors. The components of engineering structure and test pieces in thelaboratory are also different. Therefore, a systematic study on the multiaxial fatigue life predictionmethods has important theoretical significance and engineering application value.Cycle counting method is particularly important in predicting the fatigue life of engineeringstructure for we need to process large loading data. After we use a cycle counting method, we can getmany load cycles, and the value of the load cycle directly reflects the fatigue life. A new multiaxialfatigue life is proposed. In consideration of the peak and valley values of the loading strain in allloading directions, an equivalent strain is composed of these strains. Calculation process is simple.Applying an experiment conducted on304stainless steel, this method can get satisfied counting result.Applying an experiment conducted on304Lstainless steel, two multiaxial fatigue damageparameters are compared. Applying two experiments conducted on304stainless steel and En15R steel,the predicted life of the multiaxial cycle counting method presented in this paper is satisfied.