Piezoelectric composite materials

• US 4,400,642 A
• Filed: 07/12/1982
• Issued: 08/23/1983
• Est. Priority Date: 07/12/1982
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Kiraly, Louis J.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US06/397,281
• Time in Patent Office: 407 Days
• Field of Search: 428/292, 428/294, 428/295, 428/421, 428/422, 310/800, 310/311, 310/332
• US Class Current: 310/332
• CPC Class Codes: B06B 1/0603 using a piezoelectric bender, e.g. bimorph
• CPC Class Codes: H04R 17/08 signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/875 Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated

Abstract

A laminated structural device has the ability to change shape, position and resonant frequency without using discrete motive components. The laminate (10) may be a combination of layers (14,16) of a piezoelectrically active, non-conductive matrix material as shown in FIG. 1. A power source (22) selectively places various levels of charge an electrically conductive filaments (18,20) imbedded in the respective layers to produce various configurations shown in FIGS. 2 to 5 in a predetermined manner. The layers may be electrically conductive having imbedded piezoelectrically active filaments. A combination of layers of electrically conductive material may be laminated to layers of piezoelectrically active material.

Claims

1. A laminated structural device having the ability to change shape, position and resonant frequency without using discrete motive components comprising

piezoelectrically active composites laminated together, each of said piezoelectrically active composites containing at least one electrically conductive member, and

means for selectively placing a predetermined level of charge in said electrically conductive member thereby inducing a distortion in each of said piezoelectrically active composites whereby the device is deformed in a controlled manner.

2. A device as claimed in claim 1 including

a first layer of piezoelectrically active matrix material,

a second layer of piezoelectrically active matrix material laminated to said first layer,

a plurality of electrically conductive filaments imbedded in each of said layers, and

said means places a predetermined level of charge in each of said filaments.

3. A device as claimed in claim 2 wherein the piezoelectrically active matrix material of each of said layers is lithium niobate.

4. A device as claimed in claim 2 wherein the filaments are substantially parallel in each of said layers.

5. A laminated structural device having the ability to change shape, position and resonant frequency without using discrete motive components comprising

electrically conductive composites laminated together, each of said electrically conductive composites containing at least one piezoelectrically active member, and

means for selectively placing a predetermined level of charge in said electrically conductive composites thereby inducing distortion in each of said piezoelectrically active members whereby the device is deformed in a controlled manner.

6. A device as claimed in claim 5 including

a first layer of electrically conductive matrix material,

a second layer of electrically conductive matrix material laminated to said first layer,

a plurality of piezoelectrically active filaments imbedded in each of said layers, and

said means place a predetermined level of charge on each of said layers of matrix material.

7. A device as claimed in claim 6 wherein the filaments are substantially parallel in each of said layers.

8. A device as claimed in claim 6 wherein the filaments are lithium niobate.