The Research On Speckle Interferometry: Automatic Measurement And Applications In Engineering

Digital shearography was capable of measuring spatial derivatives of displacement directly and has become a useful NDT method for composite components in aerospace,marine,military,electronics and so on.This dissertation has studied the image processing method for the interferometric fringe patterns,multiple loading methods and the development of digital shearography system.The work of this dissertation can be divided into the following five sections:1.Digital shearography has been applied to evaluating the rubber-to-metal bonded structure and a numerical modeling was conducted to simulate the out-of-plane deformation of the rubber surface with thermal and vacuum stresses.2.A portable shearography system has been designed with integration of advanced technology.The main functions and applications were described in detail.3.A shearography system integrated with a fiber-optic illumination and a coherent fiber-optic imaging bundle was presented.The system can be a useful nondestructive tool to inspect the bonding quality of the interior surface of cylindrical vessels.4.The real time phase shifting technique was introduced into ESPI.A 3D deformation measurement system based on ESPI has been developed.The in-plane and out-of-plane deformation of a disk with the fixed support were measured with this system.5.Shearography and infrared thermography has been compared by conducting tests on a series of composite samples.The outcome can provide technical supports for the development of the integrated shearography and thermography system.