摘要
随着航空航天飞行器的高速发展,高温结构件变形准确测量变得愈发重要,而传统光学测量方法在超高温下面临图像纹理模糊、灰度集中的问题,散斑稳定存在与图像稳定采集可以有效提升应变测量精度。使用等离子喷涂金属钨粉末的方法,实现了2600℃散斑的稳定存在能力;对比金属钨与碳纤维材料在可见光范围内的黑体辐射强度,表明其在450nm处辐射差异明显,可以产生明暗的散斑纹理;使用了带通滤光片、线性偏振片和减光片抑制强烈的辐射光源和无关光污染,表明其可适用于超高温下的图像采集;使用改进的灰度均匀化方法解决超高温下灰度信息不明显的问题;通过高温2600℃拉伸试验进行比较测量,结果表明,本文提出方法所测得变形应变信息与等效引伸计相比较基本一致,弹性阶段内,两种方法的平均应变偏差小于200με。通过对同一批次加工的多个试件的重复测量可知,提出方法的多次测量平均偏差小于100με。最后,在110℃下进行蠕变试验,使用了高温喷漆和线性滤光片测得3D打印高分子材料在高温下的蠕变行为,验证了所提出方法在高温蠕变方面的精度和有效性。
With the rapid development of aerospace vehicles,accurate measurement of deformation of high temperature structure becomes more and more important,while traditional optical measurement methods face the problems of image texture blur and gray concentration at ultra-high temperatures,the stabilization of speckle and stable image acquisition can effectively improve the accuracy of strain measurement.In this study,the tungsten powder is used with plasma spraying methods to realize the stabilization of speckle at 2600℃.Then the black body radiation intensity of metal tungsten and carbon fiber material in the visible light range is compared,which showns that the obvious difference in radiation at 450nm can produce clear scattering texture.Bandpass filters,linear polarizers,and light-reducing films are used to suppress strong radiation sources and irrelevant light pollution,indicating that it can be applied to image acquisition under ultra-high temperatures.An improved gray-level homogenization method is used to solve the problem that the gray information is not obvious at high temperature.The comparison of the measurement results from the high temperature 2600℃tensile experiment shows that the deformation and strain information measured by the method proposed in this paper is basically consistent with the equivalent extensometer.In the elastic stage,the average strain deviation by the two methods is less than 200με.And through repeated measurement of multiple specimens processed in the same batch,it can be seen that the average deviation of multiple measurements of the method proposed in this paper is less than 100με.Finally,a creep experiment was carried out at 110°C.The creep behavior of 3D printing polymer materials at high temperatures was measured using high-temperature spray paint and linear filters.The accuracy and effectiveness of the proposed method in terms of high temperature creep are verified.
作者
秦强
张翔宇
郭翔
张超
Qin Qiang;Zhang Xiangyu;Guo Xiang;Zhang Chao(AVIC Aircraft Strength Research Institute,Xi'an 710012,China;School of Aeronautics,Northwestern Polytechnical University,Xi'an 710012,China;Hiwing Aviation General Equipment Co.,Ltd.,Beijing 100074,China)
出处
《航空科学技术》
2021年第10期1-11,共11页
Aeronautical Science & Technology
基金
航空科学基金(20170953010)。
关键词
高温力学性能
数字图像
高温变形
高温蠕变
高温散斑图像增强
high temperature mechanical properties
digital image
high temperature deformation
high temperature creep
high temperature speckle image enhancement
