多轴应力响应下结构振动疲劳寿命预估的时域方法研究

应用Von Mises应力准则将多轴应力响应等效合成为单轴应力,给出了基于功率谱输入和时域输入的多轴应力响应振动疲劳寿命预估方法,时域输入法的求解过程没有丢失应力分量相位的相互信息,较功率谱输入法更完备。针对激励载荷是以功率谱密度函数形式表达的,提出了Monte-Carlo伪随机历程模拟将激励功率谱转换到时域激励中,再通过时域输入法进行寿命预估的求解思路,保证了等效合成的Von Mises应力的相位信息具有实际的物理意义,可指导多轴应力响应下结构振动疲劳寿命的精确预估以及声疲劳试验研究。

Time Domain Analysis for the Estimation of Structure Vibration Fatigue Life Under Multiaxial Stress Responses

Von Mises criterion was applied to convert multiaxial stress into uniaxial one;the multiaxial stress response vibration fatigue life prediction method was proposed based on the power spectral input and time domain input.The time domain input method was found more complete than the power spectral input method,for the phase interaction of stresses did not drop out.Generally,excitatory input is expressed in the form of power spectral density,while this paper translated the input power spectral into time domain by Monte-Carlo simulation method,and then the fatigue life was calculated in time domain input method.It guarantees that the phase information of Von Mises stress has the physical designation,which offers the guidance for the accurate life prediction of multiaxial stress response and the acoustic fatigue experiment.