Applied Power Inc.

Corydon Roeseler

Andreas Hubertus Von Flotow

Mathieu Mercadal

Timothy S Mixon

Kelvin B Scribner

An apparatus for absorbing vibrations in a structural member, such as in an aircraft fuselage, has a mounting member for attaching to the structural member. Two masses are coupled in a cantilevered manner to the mounting member by a plurality of flexible rigid members, such as rods or plates, which act as a spring that allows the masses to vibrate with respect to the mounting member. The spring-mass assembly has a resonant frequency that matches the frequency of the vibrations in the structural member. A mechanism, connected between the two masses, exerts a variable force on the plurality of rigid members to compensate for changes in their stiffness due to changes in temperature and thereby maintain the resonant frequency substantially constant. Preferably the mechanism includes a bimetallic element that has a shape which changes with temperature variation to produce the variable force.

Temperature compensated passive vibration absorber

An aircraft engine is attached to the fuselage by a mounting structure that has a vibration absorbing system which includes first and second sensors to produce signals indicating vibration along two orthogonal axes. A third sensor, such as an accelerometer, is coupled to the mounting structure for sensing vibration of the engine. A tachometer circuit, connected to the third sensor, produces first and second speed signals that indicate the speeds of two rotating spools in the engine. Four vibration absorbers are attached to the engine mounting structure and controllers are provided to dynamically tune the resonant frequency of each vibration absorber in response to a unique combination of one of the two vibration signals and one of the two speed signals. Thus the vibration absorbers reduce the engine spool vibrations that are transmitted through the mounting structure along the two orthogonal axes. The resonant frequency of each absorber is altered to track variation of the vibrations due to changes in engine speed.

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Hood River, OR, United States of America

Corydon Roeseler