Composites for structural control

• US 6,048,622 A
• Filed: 02/09/1999
• Issued: 04/11/2000
• Est. Priority Date: 04/19/1994
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bent, Aaron A., Hagood, Nesbitt W. IV
• Primary Examiner(s): Krynski, William
• Assistant Examiner(s): GRAY, JILL M
• Application Number:
  US09/247,249
• Time in Patent Office: 427 Days
• Field of Search: 428/461, 428/689, 428/692, 310/357, 310/358
• US Class Current: 428/461
• CPC Class Codes: B64C 2027/7222 using airfoil deformation
• CPC Class Codes: B64C 27/72 Means acting on blades
• CPC Class Codes: H10N 30/1061 based on piezoelectric or electrostrictive fibres
• CPC Class Codes: H10N 30/204 using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
• CPC Class Codes: H10N 30/208 using shear or torsion displacement, e.g. d15 type devices
• CPC Class Codes: H10N 30/852 Composite materials, e.g. having 1-3 or 2-2 type connectivity
• CPC Class Codes: Y02T 50/30 Wing lift efficiency
• CPC Class Codes: Y10T 428/31692 Next to addition polymer from unsaturated monomers

Abstract

Composites for actuating or sensing deformation. In embodiments, the composites have a series of flexible, elongated piezoelectric fibers arranged in a parallel array with adjacent fibers separated by relatively soft polymer. The piezoelectric fibers have a common poling direction transverse to their axial extension. The composite further includes flexible conductive material along the axial extension of the fibers for imposing or detecting an electric field.

Claims

1. Apparatus for actuating directional deformation of a structural component comprising:

an array of elongated electro-ceramic fibers embedded in a polymer matrix and disposed on a face of the structural component, each fiber having an axis substantially aligned with a common fiber array axis that has an orientation, in a plane parallel with the face of the structural component, that is selected to produce a corresponding selected anisotropic actuation and a deformation of the component in a direction of the common fiber array axis when the fiber array is actuated; and

at least one electrode disposed on the fiber array to impose an actuation field on the fiber array.

2. The apparatus of claim 1 wherein the fiber array comprises a first fiber array disposed on a first face of the structural component, and further comprising:

a second array of elongated electro-ceramic fibers embedded in a polymer matrix and disposed on a second face of the structural component, each fiber having an axis substantially aligned with a common fiber array axis that has an orientation, in a plane parallel with the second face of the structural component, that is selected to produce a corresponding selected anisotropic actuation and a deformation of the component in a direction of the common fiber array axis when the second fiber array is actuated; and

at least one electrode disposed on the second fiber array to impose an actuation field on the second fiber array.

3. The apparatus of claim 1 wherein the structural component comprises two planar structural components, the fiber array being disposed on a face of each of the two components and located between the two components.

4. The apparatus of claim 1 wherein the electro-ceramic fibers comprise piezoelectric fibers.

5. The apparatus of claim 1 wherein the at least one electrode comprises two electrodes, each electrode disposed in a plane parallel with the face of the structural component on opposite faces of the fiber array.

6. The apparatus of claim 1 wherein the structural component comprises an aircraft wing.

7. The apparatus of claim 1 wherein the structural component comprises a submarine hull.

8. The apparatus of claim 1 wherein the fiber array is characterized by a common poling direction that is transverse to the plane of the structural component.

9. The apparatus of claim 1 wherein the electrode comprises a thin film electrode disposed on the fiber array in contact with the fibers.

10. The apparatus of claim 1 wherein the polymer matrix comprises a reinforcing material that restricts the fiber array to actuation substantially in a plane parallel with the face of the structural component.

11. The apparatus of claim 1 wherein the orientation of the fiber array axis comprises an angle, with respect to an edge of the face of the structural component, in the plane parallel with the structural component face.

12. The apparatus of claim 1 wherein the fiber array axis orientation is selected to produce a bending deformation of the structural component.

13. The apparatus of claim 1 wherein the fiber array axis orientation is selected to produce a twisting deformation of the structural component.

14. The apparatus of claim 1 wherein the fiber array axis orientation is selected to produce an elongation of the structural component.

15. The apparatus of claim 1 wherein the fiber array axis orientation is selected to produce a shearing deformation of the structural component.

16. The apparatus of claim 1 wherein the electrode comprises a patterned electrode.

17. The apparatus of claim 1 wherein the fiber array comprises a stack of multiple fiber layers.