Digital Projection Speckle Correlation Method And Its Application

The Digital Projection Speckle Correlation Method (DPSCM) is a non-contact full-field optical 3D profile and deformation measurement technique, which combines with 2D Digital Image Correlation Method (DICM), using LCD projector to produce random speckle that is projected on the surface of the sample. Making use of several images of the surface of the samples, it only acquires a few simple images of the surface of the samples and full-field profile measurement will be realized rapidly. The DPSCM is also an efficient way to measure 3D deformation with dynamic loads.In this thesis, the theory of 2D DIC and DPSCM have been studied and summarized. According to the DPSCM, applicable optical devices are used in measuring several standard samples and analyzing the measurement results of the experimental factors. Taking appropriate and effective measures, it will improve the measurement accuracy and speed. Then DPSCM technique is applied to the deformation measurement of the sample in the quick bulging. Under various loading conditions, that is different velocity and different medium. We measure the 3D deformation of the specimen. Through the analysis of experimental data,it comes to the conclusion that under the condition of the same soft Aluminum material and medium, different loading speed, the deformation extent of material has low sensitivity for the change of velocity; Under the condition of the same soft Aluminum material and loading speed, different mediums such as strong adhesion and weak adhesion, the weak adhesion material have a larger deformation. In the end, high-precision DPSCM technique is successfully applied to out-of-plane displacement measurement of the cantilever beam, which obtains deflection curve that is matched well compared with the theoretical value.