基于支持向量机的热喷涂层接触疲劳寿命预测

针对热喷涂层接触疲劳寿命的预测问题，利用装备再制造技术国防科技重点实验室研制的新型接触疲劳/磨损多功能试验机(RM-1试验机)，基于中心复合设计进行等离子喷涂Al₂O₃-40%TiO₂ 涂层（AT40涂层）受到接触应力、转速、涂层厚度和滑差率共同作用下的接触疲劳寿命试验，并通过扫描电镜观察涂层的失效形貌。采用3σ准则检验接触疲劳寿命试验的可靠性，将黄金分割法与信息熵理论相结合，对训练集和测试集进行划分。基于支持向量机（SVM）原理，建立综合考虑接触应力、转速、涂层厚度和滑差率的寿命预测模型。研究结果表明：在接触应力、转速、涂层厚度和滑差率共同作用下，涂层的损伤失效主要是分层失效和表面磨损；采用中心复合设计方案得到的多因素接触疲劳寿命具有可靠性；基于SVM回归理论训练的预测模型具有较高的显著性，可用于表征AT40涂层接触疲劳寿命与接触应力、转速、涂层厚度和滑差率的函数关系，为喷涂层接触疲劳寿命预测提供理论参考。

Prediction of Contact Fatigue Life of Thermal Sprayed Coating Based on Support Vector Machine

For the contact fatigue life prediction of thermal sprayed coatings，a series of contact fatigue tests of the plasma sprayed Al₂O₃-40wt% TiO₂ composite coating (AT40 coating) were conducted on a multifunctional contact fatigue/wear testing machine (RM-1 tester) developed by National Key Laboratory for Remanufacturing of Army Academy of Armored Forces by using a central composite design scheme under the action of contact stress, rotation speed, coating thickness and slip ratio. The failure morphology of the coatings is observed by scanning electron microscopy. 3σ criterion is used to test the reliability of contact fatigue life test. The training set and test set are divided rationally by the combination of the golden section method and the information entropy theory. A life prediction model considering the contact stress， rotation speed， coating thickness and slip ratio is established based on the principle of support vector machine. The results show the main damage failure of the coatings is delamination failure and surface wear under the joint action of contact stress， rotation speed， coating thickness and slip ratio，the contact fatigue life obtained by using central composite design scheme is reliable， and the prediction model based on the support vector machine theory could be used to characterize the function relationship between the contact fatigue life of AT40 coating with contact stress， rotation speed， coating thickness and slip ratio. These results could provide theory support to the prediction of contact fatigue life of sprayed coatings.