A Device to Determine the Out-of-Plane Displacement of a Surface Using a Moire Fringe Technique.

: A brief review of various techniques to produce moire patterns for use in making in-plane and out-of-plane displacement measurements is presented. A detailed description of a device which uses one of these techniques to obtain quantitative measurement of the out-of-plane displacement of surfaces experiencing dynamic stimulation is also given. High-speed photography of images formed by the device is used to provide a series of photographs which are analyzed to provide a time-sequence description of the motion of the deformed surface. Examples of measurement of the response of simulated fuel tank panels subjected to the impact of high-speed fragments and the response of aircraft transparencies experiencing a birdstrike are presented. (Author)