【摘要】 对具有空间构型的高频钎焊导管进行了随机振动疲劳试验研究，并提出了一种能考虑多轴平均应力效应的频域多轴振动疲劳寿命预测方法。首先，在宽带随机基础激励下对具有不同充液压力的高频钎焊导管实施了单轴向振动疲劳试验；然后，基于等效质量法并结合有限元分析方法，计算不同充液压力工况下钎焊导管危险点处静态应力水平；其次，基于随机振动理论并结合有限元分析方法，计算宽带频域内钎焊导管危险点处各应力分量具有多阶模态响应的功率谱密度函数；最后，运用等效Lemaitre应力准则和Goodman平均应力修正准则对不同工况下钎焊导管的振动疲劳寿命进行了预测，并与试验结果进行对比。对比结果表明，该频域多轴疲劳准则具有较高的振动疲劳寿命预测精度。更多还原

【Abstract】 Here, random vibration fatigue tests were conducted for high-frequency brazed pipe with spatial configurations, and a frequency-domain multi-axis vibration fatigue life prediction method considering the multi-axis average stress effect was proposed. Firstly, uniaxial vibration fatigue tests were conducted for high-frequency brazed pipe with different liquid-filled pressures under broadband random excitation. Then, based on the equivalent mass method and combined with finite element analysis method, static stress levels at dangerous points of brazed pipe under different liquid-filled pressure conditions were calculated. Subsequently, based on the theory of random vibration and combined with finite element analysis method, power spectral density functions of various stress components with multi-modal responses at dangerous points of brazed pipe in broadband frequency domain were calculated. Finally, the equivalent Lemaitre stress criterion and Goodman mean stress correction criterion were used to predict vibration fatigue lives of brazed pipe under different operating conditions, and the predicted results were compared with experimental ones. The contrastive results showed that the proposed frequency-domain multi-axis vibration fatigue criterion can have higher prediction accuracy of vibration fatigue life.更多还原