A new optical laser extensometer using a position sensitive detector (PSD)

In the conventional non-contact type extensometer, the deformation of a material is obtained on the time basis which requires high accurate scanning linear velocity. In this paper, a new method of the optical laser extensometer is proposed by using a position sensitive detector (PSD) which gives a direct information of the linear displacement of deformation of a material. The distance between the reflection tapes on the specimen can be obtained by using the signals from the photo-TR and the PSD while the laser beam scans along the specimen. The optical system of the proposed system, signal processing, control of the reflection motor, and experimental result are presented.