【摘要】 本文讨论在复杂载荷下疲劳(裂纹形成)寿命的估算方法。文中首先着重介绍局部应力-应变法的原理和应用,并通过带孔铝合金试件在随机载荷谱下的疲劳寿命计算实例加以具体说明。其次,本文还用传统的名义应力法作了疲劳寿命估算。对名义应力法,文中用了随机(块)谱及变均值、常均值、等损伤、主峰值等程序块谱。最后,本文把按局部应力-应变法及名义应力法所得疲劳寿命计算结果与已有的试验结果进行了分析比较。更多还原

【Abstract】 Fatigue (information) life predictions under complex loading are discussed in this paper.The principle and application of local strain method is presented in detail and the fatigueinformation lives of an aluminum alloy specimen with a central hole under random loadingand spectrum-type loadings using the local strain method are also presented. The tradition-al nominal stress method is used directly. In the nominal stress method, we use differentcalculations and simplified methods to treat the random load (strain)-time history in orderto obtain different program spectra. Then we use the linear damage theory and S-N curveof the material to calculate the fatig ue lives of the same aluminum alloy specimen underrandom loading and different program spectrum loadings. The results of the fatigue life calculation are compared with experimental ones and itis thought that the local strain method is a better fatigue information life estimation method,but the traditional nominal stress method still has its use value in engineering.更多还原