DOUBLE EXPOSURE INTERFEROMETRIC ANALYSIS OF STRUCTURES AND EMPLO YING AMBIENT PRESSURE STRESSING.

摘要

in order to detect defects in the surface of a tire of a vehicle, the tire (24) is placed in a sealed chamber under pressure (12 and 14).and the pressure is reduced rapidly to a very low level, and is maintained at that level for a period of time.the body of the tire (24) flue for a period of time after the change of the pressure as a result of the constraints imposed by the change of pressure.during this period, creepa section of the tire surface is illuminated with a coherent light, and two separate exposures of interferogramme are conducted by using the reflected light, and they are recorded as sinternational labour organization (ilo) on a photographic medium, on the cathode of a television image tube.the exposure may be holographic, in which case the interferogramme is produced by using a reference beam of light from light source to the surface of the object.is cisaillographique, where two images taken from the section of the surface of the tire is formed on the photosensitive medium, displaced with respect to one another and overlapping.the hologram or cisaillogramme is treated normally to take an image of the surface of the object containing the sections arranged in rows as a function of the deformation of the surfacethe two exhibitions.the fringes are analyzed by a computer or by an operator to detect anomalous segments for families of faults under the surface of the section of the tire.