Abstract: On the basis of the Goodman stress diagram and the fourth strength theory,a method is suggested to get an equivalent stress for high-low frequency compound circulating stress,The stress and strength are simulated statisitcally with the Monte-Carlo method,and their distributions are fitted.The model of stress-strength interference is applied to the strength reliability calcula-tion,A method is put forward to calculate the yield,fracture and fatigue reliability of axial rnachine parts under single-working and multiworking conditions. and the calculation program is compiled.The calcuktion results indicate that the method is satisfactory.

Key words: high frequencies-low frequencies-cycles stress, shafts (maehina elements) strength-re-liability, Monte-Carlo method