粗糙表面弹塑性接触连续光滑指数函数模型与法向接触刚度研究

发布时间：2018-03-06 01:22

本文选题：无量纲法向接触刚度　切入点：无量纲法向接触载荷　出处：《西安交通大学学报》2016年07期 　论文类型：期刊论文

【摘要】：针对微凸体在完全弹性、弹塑性和完全塑性变形阶段接触载荷和接触面积的不连续、跳跃和不光滑,以及平均接触压力的不单调问题,提出了一种新颖的近似指数形式的解析模型。在此基础上,利用分形理论进一步建立了粗糙表面在三阶段接触时的法向接触刚度和法向接触载荷与真实接触面积之间的解析模型,并进行了无量纲化处理。仿真分析了分形维数D、塑性指数Φ以及无量纲分形粗糙度参数G*对无量纲法向接触刚度K*_n和无量纲法向接触载荷F*_n的影响规律,并分析了K*_n随F*_n的变化规律。模型的仿真结果表明:K*_n和F*_n都随着无量纲真实接触面积A*_r的增大而增大;随Φ的增大或G*的减小,K*_n和F*_n的增速都变大;F*_n的增速随D的变化是先减小后增大,而K*_n的增速是指数增大;K*_n随F*_n的增大而增大,在D从1.1到1.9的变化过程中,K*_n随F*_n的增速是先增大后减小,在D1.51时,随着G*的减小,K*_n随F*_n的增速明显变大。利用法向接触刚度模型计算了哑铃模型的固有频率,计算结果与实验结果比较一致,验证了模型的准确性。
[Abstract]:In view of the discontinuity, jump and unsmoothness of contact load and contact area of microconvex body during complete elastic, elastoplastic and complete plastic deformation, and the non-monotone problem of average contact pressure, A novel analytical model in approximate exponential form is proposed. Based on the fractal theory, an analytical model of the normal contact stiffness and the normal contact load and the real contact area of the rough surface during the three-stage contact is established. The effects of fractal dimension D, plasticity index 桅 and dimensionless fractal roughness parameter G * on dimensionless normal contact stiffness Knn and dimensionless normal contact load Fnn are simulated and analyzed. The simulation results of the model show that both of them increase with the increase of the dimensionless real contact area (Atir). With the increase of 桅 or the decrease of G *, the growth rate of both KS _ n and F _ S _ n increases. The growth rate of Fexisting _ n decreases first and then increases with the change of D, while the growth rate of Kapn increases exponentially with the increase of Fiston. In the process of D changing from 1.1 to 1.9, the growth rate of KT _ n increases first and then decreases with the increase of D _ 1. At D 1.51, with the decrease of G ~ *, the growth rate of KT _ n increases obviously with the increase of F _ T _ n. The natural frequency of dumbbell model is calculated by using the normal contact stiffness model, and the natural frequency of the dumbbell model is calculated by using the normal contact stiffness model. The calculated results are in good agreement with the experimental results, and the accuracy of the model is verified.
【作者单位】：太原科技大学机械工程学院;
【基金】：国家自然科学基金资助项目(51275328)
【分类号】：O343.3

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