Structural mode shape alignment

摘要

A method is disclosed for reducing noise and vibration within a structure of a mobile platform, wherein the noise and vibration are at least in part caused by airflow over an outer skin of the mobile platform parallel to a longitudinal line extending fore to aft along the structure. The method may involve forming the structure such that a fundamental panel vibration mode shape of the structure is not parallel to the longitudinal line.

主权项

1. A method for reducing noise within a jet aircraft, wherein the noise is at least in part caused by a turbulent boundary layer flow of air over an outer surface of a skin of the jet aircraft, the method comprising:
forming a fuselage of the mobile platform with a plurality of stringers and a plurality of frame members the mobile platform comprising a jet engine able to attain an airspeed of about 500 mph; further forming the fuselage so that both the plurality of stringers and the plurality of frame members are oriented non-parallel to a longitudinal axis extending fore to aft along the fuselage; and securing a skin to the plurality of stringers and the plurality of frame members, for supporting the skin, wherein the nonparallel arrangement of the plurality of frame members and the plurality of stringers, relative to the longitudinal axis, provides a fundamental vibration mode shape for the skin that is not parallel to a direction of flow of the turbulent boundary layer flow.