Vibration of Instrument-Boards and Airplane Structures 320010
THIS paper supplements one on the same subject by the same author, published in October, 1931, and describes a new and improved three-component vibrograph with which separate vibrograms of the three components can be obtained simultaneously and with considerable magnification.
A short mathematical analysis is given to show the fundamental difference between vibrographs and accelerometers.
Effects of vibration on different instruments are discussed and the approximate maximum permissible amplitude of vibration at cruising-speed frequency for various instruments is presented in a table.
Consideration is given to correct design of instrument-boards and their suspension in an airplane, and the theory of forced vibration with damping is reviewed to show that, if not rightly chosen, shock-absorbing materials can do as much harm as good.
Other subjects discussed are the physiological aspect of vibration, the sources of vibration, the common peculiarities of vibrations from similar types of installation and miscellaneous uses of the vibrograph.
The author concludes with recommendations as to further study of vibration problems in airplane design.