Controlled friction damping device
AssigneeEuropean Aeronautic Defence and Space Company Eads France
InventorBenoit Petit Jean
Life of this patent
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Abstract
A semi-active device is used to damp vibrations moving relative to two elements between which the device is fixed. This device includes: a first member extending axially along a longitudinal axis; a second member extending axially along the same longitudinal axis, the two members being guided translatably relative to one another; a friction element extending between the two members and connecting them completely to each other by friction in an axial translational direction for any force below a threshold ‘s’, the force tending to create a relative translational movement of the two members along the longitudinal axis; an adjustment device enabling the value of the threshold to be adjusted. Thus adjusting the slip threshold of the friction element enables the dissipation conditions to be adjusted.
Claims4
A damping device comprising:
- a first cylindrical member extending axially along a longitudinal axis;
- a second cylindrical member extending axially along the same longitudinal axis and having grooves separating said second cylindrical member into angular sectors, said second cylindrical member being slidable in said first cylindrical member;
- a plurality of friction elements extending radially between the first and second cylindrical members and connecting them completely to each other by friction in an axial translational direction for any force below a threshold of a predetermined value, said force tending to create a relative translational movement of the first and second cylindrical members along said longitudinal axis;
- an adjustment device comprising a plurality of piezoelectric actuators, each acting in a radial direction and adjusting the predetermined value of said threshold;
- and
- means, remote from the first and second cylindrical members, for controlling contact pressure of the plurality of friction elements on a surface of at least one of the first and second cylindrical members, in a range that includes zero and non-zero contact pressure.
A method for controlling a tank fastening device for a fuel tank in a body of a launch vehicle, the tank fastening device including a damping device comprising a first cylindrical member extending axially along a longitudinal axis, a second cylindrical member extending axially along the same longitudinal axis and having grooves separating the second cylindrical member into angular sectors, the second cylindrical member being slidable in the first cylindrical member, a plurality of friction elements extending radially between the first and second cylindrical members and connecting them completely to each other by friction in an axial translational direction for any force below a threshold of a predetermined value, the force tending to create a relative translational movement of the first and second cylindrical members along the longitudinal axis, an adjustment device comprising a plurality of piezoelectric actuators, each acting in a radial direction and adjusting the predetermined value of the threshold, and means, remote from the first and second cylindrical members, for controlling contact pressure of the plurality of friction elements on a surface of at least one of the first and second cylindrical members, in a range that includes zero and non-zero contact pressure,
- the method comprising the steps of:
- adjusting the contact pressure between the first and second cylindrical members of the damping device such that the predetermined threshold is substantially equal to 0;
- adjusting the contact pressure between the first and second cylindrical members of the damping device such that the predetermined threshold is other than 0, so as to damp the fuel tank's vibrations;
- and
- selecting one of the two adjusting steps according to a flight phase of the launch vehicle.
Dependencies are inferred from the claim text.