考虑尺度的结合面切向刚度模型

Model of Tangential Stiffness of Joint Surface Considering Scale

接触刚度是结合面特性中最重要的参数之一,直接影响着机械结构整体的动力学特性。GW(Greenwood&Williamson)模型是目前被广泛应用的结合面接触模型,在许多实验中取得了较好的预测结果。理论上,GW模型预测结果受仪器分辨率影响,预测值并不唯一,但是实验得到的宏观物理量如刚度、导电率等却是唯一值。这一矛盾说明,存在一个唯一的计算或者观测尺度以确保宏观结果的唯一性。理论上分析了GW模型的尺度依赖特性;研究了采用高斯滤波器实现计算尺度变换的方法;基于Thomas的接触理论,设计了确定滤波器截止频率的迭代方法;最终提出了一种考虑尺度的结合面切向刚度计算框架。搭建了切向刚度试验台,对考虑尺度的切向刚度模型进行验证。结果表明,考虑尺度的模型与实验结果吻合较好。

Contact stiffness is one of the most important parameter in the characteristics of joint surface,which directly affects the dynamic characteristics of the whole mechanical structure.GW(Greenwood & Williamson) model is a widely accepted contact model and has obtained good agreement with many experiments.Theoretically,the prediction results of GW model are affected by instrument resolution,consequently are not unique,but macroscopic physical parameters such as stiffness and conductivity are unique values.This contradiction implies that there is a single computational or observational scale to ensure the uniqueness of macroscopic results.The scale-dependent characteristics of GW model are analyzed theoretically.The method to change the computing scale by Gaussian filter is researched.Based on Thomas' contact theory,an iterative method is designed to determine the cutoff frequency of the filter,and a stiffness calculation framework for the joint surface taking scale into consideration is ultimately proposed.A tangential stiffness test-bed is built to verify the model considering scale.The results show that the model considering scale can better consist with the experimental results.