摘要
针对应变计式轮轨力测量方法的不足,研究一种基于数字图像相关法的非接触式轮轨力测量方法。通过受力分析以及有限元计算,确定钢轨表面非接触测点区域位置。根据轨旁检测的特点设计测量系统的整体方案并分析了其测量原理,对相机进行了分析选型,以实现轮轨力作用下钢轨表面测点区域变形散斑图像的高质量采集。基于数字图像相关法对所采集的变形散斑图像进行分析,采用1阶形函数描述钢轨的变形,并使用零均值归一化差值平方和函数作为相似度的度量指标;为了提高系统的测量分辨精度,在整像素匹配算法的基础上,通过对位移初值进行迭代计算进一步得到亚像素级位移,并使用最小二乘法拟合位移场结果得到相应的应变场。在实验室设计并搭建了具有移动加载功能的轮轨力测量试验系统;通过静态标定试验准确建立了反映钢轨应变和轮轨垂向力大小数学关系的线性标定曲线,并分析讨论了相机工作距离和光照强度等因素对轮轨力测量的影响;在移动载荷作用下进行了轮轨力动态测量试验,与接触式应变计法测量结果进行比较,非接触式数字图像相关法在跨中位置的最大轮轨力测量误差不超过0.3%。动静态测量试验结果表明,数字图像相关法能够实现轮轨力的精确测量,是一种有效的非接触式轮轨力测量方法。
Aiming to address the shortcomings of the strain gauge type wheel-rail force measurement method,this paper studied a non-contact wheel-rail force measurement method based on the digital image correlation method.The position of the non-contact measurement points on the rail surface was determined through force analysis and finite element calculations.Considering the trackside measurement,the overall scheme of the measurement system was designed,and its measurement principle was analyzed.The camera was carefully selected to capture high-quality deformation speckle images of the rail surface measurement area under the action of wheel-rail force.Based on digital image correlation method,the collected deformation speckle images were analyzed,including using a first-order shape function to describe the deformation of the steel rail,and using the zero-mean normalized sum of squared differences function as an index of its shape similarity.Moreover,to improve the measurement resolution accuracy of the system,on the basis of the whole-pixel matching algorithm,sub-pixel level displacement was further obtained by iterating the initial displacement value,and the corresponding strain field was obtained by fitting the displacement field using the least squares method.A wheel-rail force measurement test system with the capability of moving loading was designed and built in the laboratory.Static calibration tests accurately established a linear calibration curve reflecting the mathematical relationship between rail strain and wheel-rail vertical force.Additionally,the influence of factors such as the camera working distance and light intensity on the wheel-rail force measurement was analyzed and discussed.Dynamic measurement tests of wheel-rail force were also conducted under moving loading conditions.Compared with the measurement results of the contact strain gauge method,the maximum error of the non-contact digital image correlation method at the mid-span position does not exceed 0.3%.The results of static and dynamic measureme
作者
钟昊
王雪梅
倪文波
魏丞耀
丁军君
ZHONG Hao;WANG Xuemei;NI Wenbo;WEI Chengyao;DING Junjun(School of Mechanical Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第6期2453-2464,共12页
Journal of Railway Science and Engineering
基金
四川省国际科技创新合作项目(2022YFH0038)。
关键词
轮轨力
数字图像相关法
散斑图像
亚像素匹配
试验研究
wheel-rail force
digital image correlation method
speckle images
sub-pixel matching
experimental study
