Distributed Parameter Vibration with Structural Damping and Noise Excitation

A method is described for the electronic analog computer that will permit the determination of the vibration amplitude responses of a distributed system with structural damping to a random-noise excitation such as might be experienced by a missile structure accelerated by a jet propulsion system. There is general agreement among the investigators in the literature that structural damping is both frequency independent and amplitude dependent. Simulation of the structure by a method of normal modes permits the introduction of a discrete equivalent viscous-damping coefficient for each mode frequency, thereby effecting the frequency-independent characteristic of structural damping.