Zhou Jianjun, Yang Bowen, Li Shuaiyuan, Huo Junzhou
State Key Laboratory of Shield Machine and Boring Technology, Zhengzhou 450001, China.
School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China.
Materials (Basel). 2023 May 4;16(9):3521. doi: 10.3390/ma16093521.
Micro relative sliding exists on the contact surface of the main primary equipment's surface structures, resulting in serious fretting fatigue. The plastic effect causes serious fatigue to the structure under alternating loads. Existing fatigue life prediction models fail to fully consider the shortcomings of fretting and plastic effects, which causes the prediction results to be significantly different to real-lifeworld in engineering situations. Therefore, it is urgent to establish a fretting damage fatigue life prediction model of contact structures which considers plastic effects. In this study, a plastic fretting fatigue life prediction model was established according to the standard structural contact theory. The location of dangerous points was evaluated according to a finite element simulation. The cyclic load maximum stress value was compared with the fretting fatigue test data to confirm the error value, and the error between the proposed fretting fatigue life model and the test value was within 15%. Concurrently, we combined this with mass data analysis and research, as it is known that the contact zone parameters have an impact on fretting fatigue and affect the structural lifespan. With the help of ABAQUS, the fretting numerical calculation of the dovetail tenon model was carried out to analyze the sensitive factors affecting the fretting fatigue life of the dovetail tenon structure. By keeping the fretting load unchanged, the contact area parameters such as contact surface form, contact area width and friction coefficient were changed in order to calculate the fretting stress value, and the dovetail structure was improved to extend its fretting fatigue life. Finally, it was concluded that fretting fatigue was most sensitive to the width and contact form of the contact area. In actual engineering design, multiple factors should be considered comprehensively to determine a more accurate and suitable width and form of the contact area. For the selection of friction coefficient, on the premise of saving costs and meeting the structural strength requirements, the friction coefficient should be as small as possible, and the problem can also be solved through lubrication during processing.
在主要一次设备表面结构的接触面上存在微观相对滑动，导致严重的微动疲劳。塑性效应会使结构在交变载荷作用下产生严重疲劳。现有的疲劳寿命预测模型未能充分考虑微动和塑性效应的缺点，这使得预测结果在工程实际情况中与实际寿命有显著差异。因此，迫切需要建立一种考虑塑性效应的接触结构微动损伤疲劳寿命预测模型。在本研究中，根据标准结构接触理论建立了塑性微动疲劳寿命预测模型。通过有限元模拟评估危险点的位置。将循环载荷最大应力值与微动疲劳试验数据进行比较以确定误差值，所提出的微动疲劳寿命模型与试验值之间的误差在15%以内。同时，结合大量数据分析研究，因为已知接触区参数会对微动疲劳产生影响并影响结构寿命。借助ABAQUS对燕尾榫模型进行微动数值计算，分析影响燕尾榫结构微动疲劳寿命的敏感因素。在保持微动载荷不变的情况下，改变接触面形式、接触面积宽度和摩擦系数等接触面积参数以计算微动应力值，并对燕尾榫结构进行改进以延长其微动疲劳寿命。最后得出结论，微动疲劳对接触面积的宽度和接触形式最为敏感。在实际工程设计中，应综合考虑多个因素来确定更准确合适的接触面积宽度和形式。对于摩擦系数的选择，在节约成本和满足结构强度要求的前提下，摩擦系数应尽可能小，也可在加工过程中通过润滑来解决该问题。
