STRAIN MEASUREMENT IN MATERIAL TESTING BY OPTICAL FIELD METHODS

Abstract A summary will be given of the characteristics and properties of optical field methods. The methods have achieved a high technological level during the last few years, due to the advancements in modern optoelectronic components and the development of digital image processing of optical signals. These signals are the information carriers of the searched geometrical characteristics of the considered object. The paper is divided into three parts. First, the object grating method and the electronic speckle pattern correlation interferometry are presented. In general these methods lead directly to displacement fields. The associated strain values have to be determined from these fields numerically. Several related procedures, which are practicable and of high precision, will be introduced. Finally, three examples will demonstrate the applicability and the advantages of these field methods related to various problems in material testing.