Controls of Aeronautical Structures under Fatigue Testing by Holographic Pulsed Lasers Interferometry

摘要

A compact and mobile holographic camera is described which is capable of recording holograms by double exposure. The time lapse between the 2 laser impulses (duration 20 ns, energy 100 mJ approx.) is adjustable from 0.1 micron to infinity. The successful 'in situ' experimentation of this device took place while bars of aeronautical structures were being tested for fatigue (periodical tensile stress). The holograms were recorded without interrupting the fatigue testings which lasted several hours. The testbars being used were chosen because their characteristics demonstrate problems typically met in aeronautics.