固定结合面刚度分形模型

Stiffness Fractal Model for Fixed Joint Interfaces

摘要:

基于粗糙表面统计学参数与表面轮廓分形参数之间的关系，给出了结合面等效粗糙表面轮廓分形参数的计算方法；在此基础上，提出了结合面切向接触刚度的修正分形模型；为验证模型的正确有效性，将固定结合面等效为若干个法向和切向接触弹簧单元，其刚度通过相应的接触刚度模型进行计算，进而对文献[9]的结合面实验装置——哑铃模型进行了有限元建模及模态分析，间接证明了接触刚度的正确有效性，并探讨了等效接触弹簧单元的刚度、数量对有限元建模精度的影响。此外，对文献[8]的实验模型进行了有限元建模及谐响应分析，并对实验模型的实测、柔性连接仿真与刚性连接仿真频响曲线进行了对比，进一步证实了在仿真建模过程中考虑结合面接触刚度的必要性。

关键词:结合面;分形模型;接触刚度;模态分析;频响函数

Abstract:

Based on the relationship between the rough surface statistics parameters and surface profile fractal parameters, a method for calculating equivalent rough surface fractal parameters was proposed. Furthermore, tangential contact stiffness model was modified. The FEM and modal of the dumb-bell could be obtained when the joint interface was equivalent to the spring elements whose stiffnesses were obtained from the contact stiffness model and evident the effectiveness of the contact model, then the major factors of the modeling accuracy from the stiffness and the numbers of the equivalent spring element was discussed. In addition, the FEM of another dumb-bell was obtained similarly. The frequency response functions (FRFs) of the flexible connection FEM model and the rigid connection FEM model could be obtained from the result of the harmonic response analysis. Through the comparison of the FRFs, the necessity of the research on contact stiffness model was confirmed. 

Key words:Joint interface;Fractal model;Contact stiffness;Modal analysis;Frequency response functions