齿间接触应力分布实验测试技术及分析方法研究

In this project, a temporal sequence digital image correlation technique would be proposed, with which the three-dimensional deformation of a sub region could be obtained from the sequence accessed deformation images of contacted gears. The normal 2D (X-Y) sub regions would be instead of 3D (X-Y-t) sub regions in this algorithm, and the deformation of sub regions could be calculated from two 3D images between Δt, thus the average effect of image correlation method could be reduced Effectively. A special experiment setup with two observation areas and two resolutions would be applied to solve the stress concentration problems of contact. Two image acquisition systems were set up in our experiment, one for whole field image acquisition and another for stress concentration area. Compared with the first one, the second system has a larger optical magnification and a larger grabbed image. The measurement method of contact stress and a verification method for contact theory based on experiment would be expected to proposed in this project by the measurement of displacement and strain/stress of the ends of the contacted gears and the calculation analysis of stress distribution along tooth width direction using contact theory and finite element method in which the rationality of finite element analysis model was verified from experimental data.

本项目以最常见的齿接触为研究对象，提出时间序列数字图像相关技术，通过连续获取试件的变形图像，得到子区的三维变形信息。该算法将普通的二维（XY空间）子区图像转化为三维（XY空间t时间）子区，计算Δt时间前后的子区变形，可以有效减少图像相关的平均效应。针对接触中的应力集中问题，采用双区域、双分辨率相关的实验方法。在实验中布置两路图像采集系统，一路采集全场变形数据，另一路针对应力集中区域，增加成像系统光学放大倍数，将应力集中区域图像放大，重点分析应力集中问题。通过测量每个齿接触区域的两端面的位移场、应变/应力场和应力集中状况，再结合接触理论和有限元方法，计算分析沿齿宽方向的应力分布状态，最终实现一套以实验数据为基础，用实测数据验证有限元分析模型合理性接触应力测量计算方法，并为接触理论提供可靠的实验验证数据。

本项目发展了时间序列数字图像相关技术，减少了传统数字图像相关中的平均效应，有效地提高了方法在测量弹性变形中的分辨率及精度。发展了多分辨率的数字图像相关技术，重点分析了应力集中现象，包括应力集中区域、应变集中系数等。基于实验结果以及接触理论，提出了应力反演方法，实现了非协调接面的法向力及切向力的实验测试与分析。基于上述技术研究了叶根轮槽接触中的全场变形以及应力/应变集中现象，分析了接触状态对于变形及应力分布的影响。该项目的研究对于接触变形及应力测试、多齿结构的接触特性以及非协调接触问题的变形机制等重要科学问题提供了新的实验分析手段，具有重要的科学价值与良好的工程应用前景。