STRUCTURAL MATERIAL WITH PIEZOELECTRIC MATERIAL PARTICLES

• US 20080179993A1
• Filed: 01/30/2007
• Published: 07/31/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Sanderson, Terry M.
• Granted Patent: US 7,411,338 B1
• Time in Patent Office: Days
• US Class Current: 310/319
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 2291/0232 Glass, ceramics, concrete or stone
• CPC Class Codes: G01N 2291/0235 Plastics; polymers; soft materials, e.g. rubber
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 2291/02827 Elastic parameters, strength or force
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/2475 Embedded probes, i.e. probes incorporated in objects to be inspected
• CPC Class Codes: G01P 15/0885 by magnetostrictive pick-up
• CPC Class Codes: G01P 15/09 by piezoelectric pick-up

Abstract

A load-bearing structural member has a continuous structural material with piezoelectric material particles mixed in throughout. The structural material may be any of a variety of suitable materials, such as polymer materials, composite materials, ceramic materials, or concrete. The piezoelectric material particles may be used for evaluating the soundness of the structural member, such as in quality control or structural health monitoring processes. The structural member may include one or more conductive pickups used for receiving signals from the structural member. The signals may be induced by introducing ultrasonic signals or vibrational resonance signals into the structural member. The response from such induced signals may be used for quality control purposes or structural health monitoring. Piezomagnetic, electro-strictive, or magneto-strictive material particles may also be spread throughout the structural material, to amplify and otherwise enhance the signals from the piezoelectric material particles.

Claims

1. A structure comprising:

a load-bearing structural member that includes a continuous structural material, and a plurality of piezoelectric material particles distributed within the continuous structural material; and

at least one conductive pickup attached to the structural member and operatively coupled to the piezoelectric material particles.

2. The structure of claim 1, wherein the piezoelectric material particles are distributed substantially uniformly throughout the continuous structural material.

3. The structure of claim 1, wherein the continuous structural material includes a polymer material.

4. The structure of claim 1, wherein the continuous structural material includes a composite material.

5. The structure of claim 1, wherein the continuous structural material includes a ceramic material.

6. The structure of claim 1, wherein the continuous structural material includes concrete.

7. The structure of claim 1, wherein the structural member also includes a plurality of piezomagnetic, electro-strictive, and/or magneto-strictive material particles distributed within the continuous structural material.

8. The structure of claim 1, wherein the at least one conductive pickup includes multiple conductive pickups placed at different respective locations on the structural member.

9. The structure of claim 1, wherein the at least one conductive pickup includes a conductive foil pickup.

10. The structure of claim 1, wherein the at least one conductive pickup includes a conductive paint pickup.

11. The structure of claim 1, wherein the at least one conductive pickup is on a surface of the structural member.

12. A method of evaluating structural soundness of a structural member, the method comprising:

placing at least one conductive pickup on the structural member, wherein the structural member includes a continuous structural material and a plurality of piezoelectric material particles in the continuous structural material;

exciting at least some of the piezoelectric material particles;

receiving electrical signals from the at least one conductive pickup, wherein the signals are at least in part caused by excitation of the piezoelectric material particles; and

interpreting the signals to determine the structural soundness of the structural member.

13. The method of claim 12, wherein the exciting includes subjecting the structural member to an ultrasonic signal.

14. The method of claim 12, wherein the exciting includes subjecting the structural member to a vibrational resonance signal.

15. The method of claim 12, wherein the interpreting includes comparing the signals to signals obtained from evaluating other similar structural members.

16. The method of claim 12, wherein the exciting includes enhancing excitement of the piezoelectric material particles through a plurality of piezomagnetic, electro-strictive, and/or magneto-strictive material particles that are also in the continuous structural material.

17. A method of detecting acceleration in a vehicle, the method comprising:

placing at least one conductive pickup on a structural member of the vehicle, wherein the structural member includes a continuous structural material, and a plurality of piezoelectric, piezomagnetic, magneto-strictive, and/or electro-strictive material particles in the continuous structural material; and

receiving electrical signals from the at least one conductive pickup, wherein the signals are indicative of electrical fields in the structural member caused by stresses induced in the structural member by acceleration of the vehicle.

18. The method of claim 17, wherein the detecting acceleration is used to control arming of a weapon.