【摘要】 提出一种基于权平均最大剪切应力临界面的疲劳寿命预测方法。首先,基于改进的Wang-Brown多轴计数法,提出了一种多轴载荷下临界面的确定方法,该方法通过权平均所有计数反复中具有较大法向拉伸应力的最大剪切应力平面的位相角来确定整个载荷历程的临界面,提出的权函数定义为各个计数反复中的剪切应力范围与所有反复中最大剪切应力范围的比值。提出的临界面确定方法通过7050-T651铝合金薄壁管试验数据来进行验证。然后,结合提出的临界面确定方法,高周疲劳损伤准则和Miner线性损伤法则来建立多轴变幅载荷下疲劳寿命预测方法。最后,采用7050-T651和2024-T4铝合金试验数据来验证提出的疲劳寿命预测方法的准确性,结果表明提出的方法具有较好的预测效果。更多还原

【Abstract】 A fatigue life prediction methodology is proposed based on weight-averaged maximum shear stress range plane.Firstly,based on modified Wang and Brown’s reversal counting method,a new approach to the determination of the critical plane is proposed under multiaxial variable amplitude loading. For the entire loading history,the orientation angle of the critical plane is determined through averaging the orientation angles of maximum shear stress range planes with largest normal tensile stress in all counted reversals. The weight function is defined as the ratio of maximum shear stress range for every counted reversal to the largest shear stress range for all counted reversals. The accuracy of the proposed critical plane approach is verified using experimental data of 7050-T651 aluminium alloy notched tubular specimens. Then,the proposed determination approach of critical plane is combined with multiaxial high-cycle fatigue criterion and Miner damage rule to establish the fatigue life prediction methodology under multiaxial variable amplitude loading. Finally,the proposed fatigue life prediction methodology is verified by the experimental data of 7050-T651 and 2024-T4 aluminum alloy notched tubular specimens,and the results show that the proposed methodology has good prediction results.更多还原