APPLICATION OF OPTICAL TECHNIQUES TO MOVING SURFACE MEASUREMENTS (MOIRE FRINGE CONTOUR MAPPING, FRINGE ANALYSIS)

Available from UMI in association with The British Library.; The objective of this study was to investigate Moire fringe contour mapping techniques and their application to specific surface mapping problems.; Moire fringes are formed by the superposition of two gratings. Under certain geometrical conditions the fringes formed represent equal depth contours on the surface under scrutiny.; Shadow Moire topography was used to generate a contour pattern on the rear surface of steel plate under ballistic impact loading. Tests were carried out using a Luger pistol firing 9mm bullets, at a velocity of 300m/s, at 3mm steel plate.; The second area of interest was the water surface behaviour beneath an oil-rig type structure subjected to waves. Projection Moire provided the measurement method for model testing of two different structures.; The difficulties which arose from mapping of both types of surface and computer fringe analysis techniques, which extracted surface detail, are described. Conclusions are reached regarding the respective successes of the Shadow and Projection Moire techniques. Suggestions for potential advances are discussed.