Rapid S-N curve prediction of Q460 welded joints based on energy dissipation

In view of the characteristics of the traditional S-N curve requiring long test period and large number of samples,a three-parameter S-N curve rapid prediction model combined with the high cycle fatigue life,fatigue limit and statistics of welded joints was presented. Through determining the turning point of energy dissipation in stable temperature rise stage under gradually increasing of load,and this turning point was then regarded as an index for predicting the fatigue limit. Considering the cumulative damage threshold in the whole lifespan when the load was above the fatigue limit,a median S-N curve prediction model based on the energy dissipation threshold was established. Then,combined with the maximum likelihood method,the S-N curve prediction with the survival probability of 95% was completed. To verify the validity of the proposed model,the predicted S-N curve was compared with the experimental data. Results showed that the experimental data were basically distributed between the median S-N curve and the S-N curve with 95% survival probability,which verified the accuracy of the model.