Instrumentation and techniques for structural dynamics and acoustics measurements

This paper summarizes the instrumentation and techniques used by the Structural Dynamics Branch of the Air Force Wright Aeronautical Laboratories in dynamic testing of aircraft, spacecraft, and missiles. Modal testing of aircraft is discussed, including accelerometers, automatic gain ranging amplifiers, and signal multiplexers. Laser techniques of structural motion measurement are discussed, including a description of video holography (electronic speckle pattern interferometry) and its application to modal testing of aircraft and missile components. Acoustic testing of structures at elevated temperatures is discussed, including techniques for achieving higher sound-pressure levels and the development of high-temperature accelerometers and microphones.