面-面接触铝合金紧固件微动疲劳寿命预测方法研究

针对具有面-面接触特征的铝合金紧固件,根据其接触特点,建立有限元模型计算了其应力场分布。考虑接触面高轴应力梯度的力学响应,用接触面应力三维度的概念来反映微动疲劳多轴应力状态。考虑损伤和弹塑性势能的耦合,从热力学第二定律出发,基于损伤力学本构方程,推导出基于热力学耗散势函数的耦合损伤演化模型。结合实验参数,得到预测铝合金紧固件微动疲劳寿命的方法。寿命预测结果与实验值进行对比,误差分散在25%范围内。

Study on The Fretting Fatigue Life Prediction of Aluminum Alloy Fastener Contact Surface

Aim to with face to face contact characteristics of aluminum alloy fasteners, according to the contact characteristics, the finite element model is established to calculate the stress field distribution, considering the contact surface with high axial stress gradient, the concept of three dimensional stress on contact surface is used to reflect the multi axial stress state. Considering the coupling between damage and elastic potential energy, starting from the second thermodynamic law, based on the constitutive equation of damage mechanics, the coupling damage evolution model is derived from the thermodynamic dissipation potential function. Combined with the experimental parameters, the aluminum alloy fastener fretting fatigue life predicting method are obtained, the life prediction results are compared with the experimental results , error dispersion within 25% range.