472. Weight Estimation Methods for Frequency-Limited Support Structure

Paper

Abstract

Equipment support structure in current aerospace vehicles can weigh from two to two hundred percent of the supported equipment weight. Much of this support structure is design by a minimum frequency limitation. This paper presents working tools and numerical examples for the rapid weight estimation of such structure by categorizing them as beams or plates. Beams are subdivided into uniformly loaded beams, point-loaded uniform beams, randomly loaded uniform beams, and randomly loaded nonuniform beans. Analysis of the latter is accomplished with the Rayleigh method of frequency determination. Plates are subdivided into the unloaded, uniformly loaded, and randomly loaded cases. The latter is analyzed by the Stokey-ZororJski4ppl method, which includes correction factors for the inertia of the- supported equipment. The methods presented are oriented toward minimum weight design. ‘When combined with vibration damping methods, substantial value in weight optimization can be achieved.