Holographic Analysis of Large Vehicle Structures

A highly tuned, double pulse, Q-switched ruby laser is used to make double exposure holograms of large vibrating objects. The holographic fringe patterns are interpreted to produce a detailed knowledge of the displacement amplitude for a wide variety of vibrating objects. A triggering system permits the firing of the laser relative to arbitrary phase orientations of the vibrating object. A primary emphasis is placed upon the holograms at the same amplitude and frequency but different phase angles yields valuable information about the dynamics of the vibrating vehicle components. These interferometric fringe patterns reveal important information about global displacement amplitude and stress concentrations.