Sandwich-structure flat actuator and application to structural torsion

• US 20070205332A1
• Filed: 11/16/2006
• Published: 09/06/2007
• Est. Priority Date: 11/22/2005
• Status: Active Grant

• Current Assignee: Office National D'Etudes et de Recherches Aerospatiales
• Original Assignee: ONERA
• Inventors: Mercier Des Rochettes, Hugues, Buchaniek, Leon, Joly, Didier
• Granted Patent: US 7,726,603 B2
• Time in Patent Office: Days
• US Class Current: 244/219
• CPC Class Codes: B64C 2027/7283 of the piezoelectric type
• CPC Class Codes: B64C 27/001 Vibration damping devices
• CPC Class Codes: H10N 30/208 using shear or torsion displacement, e.g. d15 type devices
• CPC Class Codes: Y02T 50/30 Wing lift efficiency

Abstract

The present invention relates to a sandwich-structure flat active actuator that is symmetrical relative to the mid-plane comprising at least one piezoelectric flat layer having an active direction superpose and fixedly attached to at least one passive flat layer of fabric with rigid warp and weft oriented in two directions forming a mesh; the two directions of each layer of fabric are the same. The active direction of each piezoelectric layer is oriented along one and the same diagonal of the mesh of the layers of fabric. The invention is also aimed at a device consisting of two actuators mounted head-to-tail. The invention applies to the active torsion of structures such as, for example, a helicopter blade.

Claims

1. A flat, sandwich-structure actuator comprising two attachment zones designed to transmit the relative shearing displacement generated, and at least three flat superposed layers comprising at least one layer of a fabric whose warp and weft consist of rigid fibers disposed in two directions of the plane, forming a mesh of juxtaposed parallelograms, and at least one piezoelectric active flat layer capable of lengthening or retracting in an active direction, each face of a layer being bonded over its whole surface to a face of the adjacent layer, wherein the sandwich structure is symmetrical relative to the mid-plane of the actuator, promoting a flat shearing deformation, the active direction of each piezoelectric flat layer is oriented along one and the same diagonal of the mesh of each layer of fabric whose warp and weft are all oriented in the same two directions of the plane, the attachment zones of the actuator, of elongated shape in a first of the two directions of the plane, are disposed along the opposite ends of the actuator in the second direction of the plane, thanks to which each flat layer of fabric being acted upon in a single diagonal of the mesh, the parallelograms deform causing the attachment zones to displace in the plane parallel with one another in the first direction of the plane.

2. The actuator as claimed in claim 1, wherein the sandwich structure consists of an active layer situated between two layers of fabric.

3. The actuator as claimed in claim 1, wherein the sandwich structure consists of one layer of fabric situated between two active layers.

4. A flat actuator device, wherein two actuators are provided as claimed in claim 1, mounted head-to-tail, two facing attachment zones of the actuators being fixedly attached and the two active directions not being parallel, the other two facing actuator attachment zones, left free, have a displacement in the first direction of the plane whose amplitude is equal to the sum of the amplitudes of the two basic actuators.

5. The use of the device as claimed in claim 4 in combination with the structure of an open airfoil, wherein the two facing attachment zones left free are fixedly attached respectively to the pressure surface and the suction surface, the device thus closing this structure in the vicinity of its trailing edge.

6. The use as claimed in claim 5, wherein the two fixedly attached facing attachment zones and the trailing edge are situated, along the chord, on either side of the two facing attachment zones left free.

7. The use as claimed in claim 5, wherein the two fixedly attached facing attachment zones and the trailing edge are situated, along the chord, on the same side of the two facing attachment zones left free, the two fixedly attached facing attachment zones forming the trailing edge of the airfoil.