高-低载荷下振动疲劳损伤累积的试验研究

In order to explore the law of vibration fatigue damage accumulation under high-low load,the axial vibration fatigue test system is designed based on the vibration table.The axial vibration fatigue test is carried out on 7050-T7451 aluminum alloy specimens,and the results are compared with the normal fatigue test results on the high frequency testing machine.The results show that both vibration fatigue and normal fatigue tests show “coaxing effect”.In the vibration fatigue test,the cumulative damage values increase with the increase of the difference between high and low loading amplitudes,the “coaxing effect” is gradually obvious; there is a critical value 0.483 of the maximum stress ratio under high-low load; when the stress ratio?σ'<0.483,the vibration fatigue loading shows more obvious “coaxing effect” than the normal fatigue loading.