Electric Speckle Pattern Correlation Technique And Its Application In Engineering Detecting

The deformation of beam bending axis(deflection) is an important parameter that reflects the mechanical properties of material. However, it is not convenient to measure the parameter by normal measuring method because of its less bending percentage. Usually, it is measured by the laser holography method. The method needs not only humidity processing, but also darkroom operation. Therefore, the application of the laser holography method is limited in the engineering practice.First of all, according to the real-time, whole-field and fast character of the related technology of Electric Speckle Pattern Interferometry (ESPI), the ESPI is used to measure the deformation displacement of beam and make the optical detection technology be used in the practical application. But the influence of environment vibration to the measurement errors is big. So the principle of Electric Shearography Speckle Pattern Interferometry(ESSPI) is stated briefly in this paper. Its system composition and measurement theory was introduced, and all of these phase measuring methods in ESSPI and the influence to the precision of these phase measuring methods was discussed.Then, the ESSPI was used in the experimental research. The temporal phase-shift method(TPM) and Spatial carrier Fourier transform method(SCFTM) of ESSPI were used to solve the differential field of displacement of the edge-clamped round board respectively. Comparing the experimental result with the theoretical result, which proves that the Spatial carrier Fourier transform method is much more superiority in dynamic inspection and has approximate precision to the temporal phase-shift method.At the last, the related technology of Electric Speckle Pattern Interferometry was used in the engineering material mechanics measurement respectively. The temporal phase-shift method of ESPI was used to measure the displacement of deformation of the beam. Its result was compared with the theoretical. And then the temporal phase-shift method and Spatial carrier Fourier transform method of ESSPI were used to measure the displacement gradient of deformation of the beam. By comparing with the theoretical results, the experimental results show that Spatial carrier Fourier transform method is a very useful measuring method and may be widely used in the engineering application.