Service life prediction of powder metallurgy parts under cyclic stress based on improved Paris-Erdogan equation
The calculation accuracy of the service life of nickel-based superalloy fork manufactured by powder metallurgy is improved by modifying the Paris-Erdogan equation.In view of the charac-teristics of crack acceleration under high stress cycles,the number of stress cycles is introduced into the material exponent of Paris-Erdogan equation to compensate for the deviations at crack accelera-tion and propagation stage,and to accurately predict the service life of the fork.To verify the calcu-lation accuracy of service life,three types of notches with lengths of 2,5 and 8 mm are prefabricated at the vulnerable locations of the forks.A pulsating cyclic stress loading test is carried to measure the service life of the fork,and the test results are compared with the calculated results.The results show that the crack propagation direction is perpendicular to the loading direction,and the service life of the three kinds of prefabricated notch fork is 372 000,194 000 and 69 000 stress cycles,respectively.The service life calculation error of the improved model is less than 6.2％,and the calculation accuracy is improved by about 40％.
万方数据
维普
