Holographic interferometry applied to the solution of a shell problem

Abstract

Two methods of holographic interferometry were applied to measure the displacements of the surface of a cylindrical shell clamped at both ends and subjected to a single radial load. In the first method the multiple-hologram technique was applied. Holograms were taken separately and the total span of the shell was recorded in separate holograms. Collimated illumination was utilized and the reconstruction pictures were taken far away from the location of the virtual image. In the second method, a modified single-hologram technique was utilized. Multiple points of observation in the plane of the hologram were employed to provide a way to minimize random errors. The first method proved to be adequate to measure displacements comprised between 10⁻⁴ to 10⁻⁵ in. The second method yielded results one order of magnitude better.