Computation of Vibration Modes and Frequencies on SEAC

Abstract

A description is given of several codes developed for use in the Standards Eastern Automatic Computer for computing the free vibration modes and frequencies of aircraft structures.The codes are general in nature and apply without modification to any aircraft structure whose influence coefficients, mass distribution, and geometry are specified. The codes are applicable when no more than 63 mass points are needed to define the displacement of the half-wing. In an example with seven mass points along the fuselage axis and 24 mass points for each half-wing, the computing time for the first six symmetric and the first six antisymmetric modes was 6 hours.