Evaluation of the effect of stopping selected frames on noise in the cabin of a propeller airplane

Abstract

A unified approach is proposed to solve vibration problems for stiffened plates, shells, and other arbitrary stiffened structures. The approach is applicable under the condition that independent solutions for the stiffened structure and the stiffening elements are known in the form of explicit expressions determining generalized displacements through generalized forces. The proposed universal equation is used to solve the problem of deterministic vibrations of a closed cylindrical shell with "smeared" stringers and irregular dis crete frames. The solution is used to estimate the effect of noise suppression achieved in the cabin of a pro peller airplane by stopping some of the frames positioned near the propeller.