Surface-strain measurements on a hemispherical shell using holographic interferometry

A method is presented for using real-time fringe counting and double-exposure single-hologram interferometry to measure surface strain on pressurized hemispherical shells. An aluminum shell is employed for experimental verification of these techniques. Surface-strain variations caused by a defect in the aluminum wall are detected and measured. Strain-gage arrays are used for comparison of experimental results. Bendix Kansas City Division is a prime contractor to the Atomic Energy Commission.