This paper presents a regression analysis of uniaxial and multiaxial fatigue life for automobile coil spring under various road excitations. Coil spring is a suspension component with complex geometry and shear loading which is applied during operating conditions. Hence, uniaxial strain measurement for durability assessment of coil spring is insufficient because the loadings are non-proportional. Rosette strain signals of coil spring under five different road conditions were obtained and used as input to uniaxial strain-life and multiaxial critical plane models to predict the spring fatigue life. During the multiaxial fatigue analysis, the strain biaxiality ratio of range 0.3 to 0.5 indicates the loadings as out-of-phase. Through a simple linear regression method, a linear regression model between uniaxial and multiaxial fatigue life were obtained with coefficient of determination value as high as 0.8696. This model provides significant contribution through correlating uniaxial to multiaxial fatigue life. Hence, uniaxial fatigue life predictions could be approximated to multiaxial for more conservative analysis through the application of generated linear models.

中文翻译：

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汽车弹簧寿命评估中单轴和多轴疲劳模型的相关性

本文介绍了汽车螺旋弹簧在各种道路激励下的单轴和多轴疲劳寿命的回归分析。螺旋弹簧是一种具有复杂几何形状和剪切载荷的悬挂部件，在操作条件下施加。因此，用于螺旋弹簧耐久性评估的单轴应变测量是不够的，因为加载是不成比例的。获得了五种不同道路条件下螺旋弹簧的玫瑰花形应变信号，并将其用作单轴应变寿命和多轴临界平面模型的输入，以预测弹簧疲劳寿命。在多轴疲劳分析过程中，应变双轴度比在 0.3 到 0.5 的范围内表明载荷是异相的。通过简单的线性回归方法，得到了单轴和多轴疲劳寿命的线性回归模型，决定系数高达0.8696。该模型通过将单轴疲劳寿命与多轴疲劳寿命相关联，做出了重大贡献。因此，通过应用生成的线性模型，可以将单轴疲劳寿命预测近似为多轴以进行更保守的分析。