Patent ID: 7631835

Claim:
A method of decoupling solidborne noise and vibration applied to a rotary wing aircraft ( 1 ) in a laminated ball joint ( 15 ) between firstly a suspension bar ( 13 ) and secondly a force transmission structure ( 7 ) and/or a case ( 9 ) of a transmission gearbox ( 4 ) of the aircraft ( 1 ), the method comprising at least the step of preparing the laminated ball joint ( 15 ) the ball joint comprising at least an outer strap ( 17 ) and a junction shaft ( 18 ) for anchoring the ball joint ( 15 ) respectively to the force transmission structure ( 7 ) or to a transmission gearbox case, and at least two damper layers ( 19 ) and an interleaved rigid layer ( 20 ), wherein a determination step prior to the preparation step provides for determining at least one frequency band for decoupling in the range 0 to 7000 Hz, the step of preparing the laminated ball joint ( 15 ) comprising a stage of allocating frequencies such that said frequency-allocation stage provides for at least two damper layers ( 19 ) and at least one interleaved rigid layer ( 20 ) to be selected respectively for dedication to at least a determined frequency band, by imposing on said layers ( 19 , 20 ) shape and dimension and physical-property parameters, said imposed parameters being such that the layers ( 19 , 20 ) perform selective decoupling at least one frequency of the determined band.