应用热弹塑性理论的结合部法向载荷分形模型

A Normal Load Fractal Model of Joint Interface Based on Thermal Elasto-Plastic Theory

针对现有法向接触载荷分形模型没有考虑热应力的影响、不适用于结合部温度变化的问题,基于热弹塑性理论和接触分形理论,建立了热弹塑性接触法向载荷分形模型。该模型是对传统模型在基础理论和应用范围上的拓展,综合考虑了温差、线膨胀系数、机械载荷比例系数等参数的影响,从而可用于计算和分析工程实际中大量存在的结合部温度发生改变的接触情况,其结果更符合客观规律。此外,针对考虑热应力的接触问题,引入机械载荷比例系数,给出了模型的另一种表达形式。通过特例验证了模型的有效性,并与前人的模型进行了对比分析,结果显示:模型间的计算结果差距随结合部温差的增大而增大。最后,通过数字仿真揭示了结合部温差对热弹塑性接触法向载荷的影响规律——热弹塑性接触法向载荷随结合部温差的增大而增大。

Without considering the influence of heat, the existing fractal contact models are not applicable to analyze the contact issues when the temperature changes. Based on thermal elasto- plastic theory and contact fractal theory, a new fractal model of normal contact load is established in this study. This model expands the basic theory and applications of traditional models, and comprehensively considers the effects of such parameters as temperature difference, linear expansion coefficient, mechanical load scale factor, etc. Therefore this model can help calculate and analyze the real contact conditions between fixed contact surfaces when the temperature changes, and it shows better conformity with objective laws. Besides, another expression of the model is proposed by introducing mechanical load scale factor. Then the model is validated through a special case, and comparative study is conducted between this model and TZQ model. The results show that the difference between the model calculations increases with the junction temperature difference. In addition, the effect of temperature difference on the normal contact load is also analyzed. The results reveal that the normal contact load of thermal elasto-plastic contact increases with the temperature difference at joint interface.