Thermal Deformation Measurement Research Articles

ホログラフィ干渉法を利用した熱変形計測 第１報 補正台による干渉じま補償法を応用した熱変形計測装置の開発

This paper describes a development of an apparatus for highly accurate measurement of a thermal deformation of a mechanical part. The apparatus makes possible a real time monitoring a microscopic change of the thermal deformation pattern by using real-time holographic interferometry. One of the most important problems to be solved on a measurement of thermal deformation is how to fix a measuring object. When environmental temperature changes, the spurious interferometric fringes are happened by an unnecessary slip between contact surfaces of the measuring object and its holder, due to thermal expansion differences between them. An adjustable correcting stand utilizing piezoelectric elements is developed for a real time compensation of the spurious fringes. The effectiveness of the correcting stand for a precise and real time measurement of the thermal deformation pattern was confirmed experimentally. An air bath that has an optically stable window for observation of the deformation from outside is used for highly accurate control of the temperature of the measuring object. The interferometric fringes are recorded on a thermoplastic plate for real time monitoring of the changing process of the thermal deformation pattern.

光ファイバを利用した干渉計による熱変形計測

This paper describes a study of an interferometer utilizing an optical fiber for highly accurate measurement of thermal deformation of a mechanical part in out-of-plane direction. This interferometer utilizes a polarization-preserving optical fiber. Two signal lights pass the same optical paths of the fiber, and the influence of the external disturbance (for example, temperature changes) to the optical paths of the fiber can be cancelled by the differential detection of the interference signals of these lights. A reference plane is set near an object plane, and an optical probe with the reference plane is composed of the materials with small thermal expantion coefficient. The experiment verified that the present interferometer worked in the same way as the theory. The present interferometer was applied to a measurement of thermal expantion, and its measuring dispersion of this interferometer was within ±60 nm.

Interactive Fringe Analysis System: Applications To Moire Contourogram And Interferogram

A general purpose fringe pattern processing facility was developed in order to analyze moire photographs used for scoliosis diagnoses and interferometric patterns in optical shops. A TV camera reads a fringe profile to be analyzed, and peaks of the fringe are detected by a microcomputer. Fringe peak correction and fringe order determination are performed with the man-machine interactive software developed. A light pen facility and an image digitizer are employed for interaction. In the case of two-dimensional fringe analysis, we analyze independently analysis lines parallel to each other and a reference line perpendicular to the parallel analysis lines. Fringe orders of parallel analysis lines are uniquely determined by using the fringe order of the reference line. Some results of analysis of moire contourograms, interferometric testing of silicon wafers, and holographic measurement of thermal deformation are presented.