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针对现有建立寿命设计曲线方法的不足,采用容限法建立寿命设计曲线,对比并分析了各种方法的差异.对于大样本的疲劳试验数据,试验结果表明在不同应力水平材料寿命的分散性不同.为此在近似Owen容限法基础上提出了一种包含应力水平的分散性模型建立设计曲线,使其能够满足材料寿命在高应力分散性较小,低应力分散性较大的特点.根据Ti-6246疲劳试验结果,利用该方法计算得到的设计寿命在疲劳载荷为925MPa时提高了146%,在820MPa时减小了60.2%.从而提高了设计的经济性和可靠性.
In order to overcome the shortcomings of existing life-span design curve methods, the tolerance curve method is used to establish the design life-span curve, and the differences between various methods are compared and analyzed. For the fatigue test data of large samples, the test results show that the dispersion of material life at different stress levels Different.Based on the approximate Owen tolerance method, this paper proposed a design model based on the dispersion model of stress level, which can meet the material life requirements of small stress dispersion and low stress dispersion. According to the fatigue test results of Ti-6246, the design life calculated by this method increases 146% when the fatigue load is 925MPa and 60.2% when it is 820MPa, which improves the economy and reliability of design.