Development of the Hybrid Laser-Speckle and Image-Analyzing Method for Measuring Deformation and Strain at Very High Temperature.

开发用于测量极高温度下变形和应变的混合激光散斑和图像分析方法。

• 批准号: 02555016
• 负责人: SUMI Seinosuke
• 金额: $ 5.82万
• 依托单位: Kyusyu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02555016/
• 关键词: Laser; Speckle Interferometry; Very High Temperature; Strain Measurement; Image Processor; High-Temperature Material; Linear Coefficient of Thermal Expansion; Vacuum; レ-ザ応用; スペックル; 変位測定; 画像処理・解析; 熱ひずみ

A electronic-speckle-pattern-interferometry (ESPI) system using a cw Ar-laser, television equipment and an image processor has been developed and applied to the strain measurement on free thermal expansion at very high temperature. ESPI provides the distribution of in-plane displacement resolved in a preselected direction. ESPI retains the merits of little or no surface preparation, no contact with the surface, and the real-time presentation of interference fringes. These permited the measurement by ESPI at very high temperature. In this case the main problems were the turbulence in the hot air surrounding a high temperature object, the background radiation from the object and the change in the microstructure of the object surface due to oxidation. These caused the reduction of fringe visibility. The problem on hot air turbulence was resolved by using a vacuum chamber. The fringes on specimens were much more stable and the amount of scatter in measured values was less in a vacuum chamber than in air. The background radiation was supressed considerably by a interference filter which was placed at the front of TV camera. The correlation of speckle patterns was reduced due to oxidation. This couldn't be avoided in low pressure about 4-10 Torr in the chamber. The thermal strains on four kinds of high-temperature metals were measured. The fringes were observable to 1200ﾟC, which spacings were calculated by FFT to avoid human error. The results measured by ESPI in low pressure were neary equal to those to 900ﾟC by speckle photography in air and the data which have already been published. The linear coefficient of thermal expansion of the alloys such as sus 430, inconel 601 and nickel chromium increased rapidly with temperature, near the anomaly point. Tantalum of refractory metal oxidized heavily.

使用连续氩激光、电视设备和图像处理器的电子散斑干涉测量（ESPI）系统已被开发出来，并应用于极高温度下自由热膨胀的应变测量，ESPI 提供了分布。在预选方向上解析的平面位移保留了很少或没有表面准备、不与表面接触以及干涉条纹的实时呈现的优点，这些使得ESPI能够在非常高的条件下进行测量。在这种情况下，主要问题是高温物体周围热空气的湍流、物体的背景辐射以及氧化导致的物体表面微观结构的变化。通过使用真空室解决了热空气湍流的问题，样品上的条纹更加稳定，并且真空室中测量值的散射量比空气中的背景辐射要少。被放置在电视摄像机前部的散斑图案的相关性由于氧化而降低，这是在室中约4-10托的低压下无法避免的。测量了四种高温金属的条纹。在 1200°C 下仍可观察到，这些间距是通过 FFT 计算出来的，以避免人为误差，ESPI 在低压下测量的结果几乎等于 900°C 下的结果。空气中散斑摄影和已经发表的数据显示，sus 430、inconel 601和镍铬等合金的线性热膨胀系数随着温度的升高而迅速增加，接近难熔金属的异常点。