Structural vibration damping device

• US 20070052325A1
• Filed: 07/14/2006
• Published: 03/08/2007
• Est. Priority Date: 09/05/2005
• Status: Active Grant

• Current Assignee: Japan Aerospace Exploration Agency
• Original Assignee: Japan Aerospace Exploration Agency
• Inventors: Takeuchi, Shinsuke, Yabu, Takuya, Onoda, Junjiro
• Granted Patent: US 7,564,163 B2
• Time in Patent Office: Days
• US Class Current: 310/314
• CPC Class Codes: F16F 15/005 using electro- or magnetostrictive actuation means generating of mechanical vibrations operating with electrostriction B06B1/06, with magnetostriction B06B1/08; vehicle suspension arrangements characterised by use of piezoelectric elements B60G17/01941; piezoelectric, electrostrictive and magnetostrictive devices per se H10N30/00

Abstract

Disclosed is a structural vibration damping device, which comprises a piezoelectric element adapted to be mounted on a structure, a shunt circuit inserted between two electrodes of the piezoelectric element, and an electric circuit for selectively opening and closing the shunt circuit. In this damping device, the electric circuit is operable, when a voltage between the electrodes of the piezoelectric element has a positive or negative extreme value due to a vibration of the structure, to close the shunt circuit so as to allow a current to flow between the electrodes of the piezoelectric element, and, when the current is reduced to zero, to open the shunt circuit so as to preclude the current flow until a voltage between the electrodes of the piezoelectric element subsequently has the extreme value. Further, each of the shunt circuit and the electric circuit is designed to be operated using only a power generated by the piezoelectric element. The damping device of the present invention makes it possible to achieve high-performance power-free damping with enhanced reliability and maintainability.

Claims

1. A structural vibration damping device comprising:

a piezoelectric element adapted to be mounted on a structure;

a shunt circuit inserted between two electrodes of said piezoelectric element; and

an electric circuit for selectively opening and closing said shunt circuit, wherein;

said electric circuit is operable, when a voltage between the electrodes of said piezoelectric element has a positive or negative extreme value due to a vibration of said structure, to close said shunt circuit so as to allow a current to flow between the electrodes of said piezoelectric element, and, when said current is reduced to zero, to open said shunt circuit so as to preclude the current flow until a voltage between the electrodes of said piezoelectric element subsequently has the extreme value; and

each of said shunt circuit and said electric circuit is designed to be operated using only a power generated by said piezoelectric element.

2. The structural vibration damping device as defined in claim 1, which is designed to allow a current flowing across said shunt circuit to pass through a coil.

3. The structural vibration damping device as defined in claim 1, wherein said electric circuit includes an extreme-value detection circuit using a peak hold circuit, and a circuit having a function of selectively opening and closing said shunt circuit in response to an output of said extreme-value detection circuit.

4. The structural vibration damping device as defined in claim 3, wherein said peak hold circuit includes a capacitor and a diode.

5. The structural vibration damping device as defined in claim 1, wherein said electric circuit includes an extreme-value detection circuit using a differentiation circuit, and a circuit having a function of selectively opening and closing said shunt circuit in response to an output of said extreme-value detection circuit.

6. The structural vibration damping device as defined in claim 5, wherein said differentiation circuit includes a capacitor and a resistor.

7. The structural vibration damping device as defined in claim 1, wherein said electric circuit is designed to selectively open and close said shunt circuit using a thyristor and a programmable unijunction transistor.

8. The structural vibration damping device as defined in claim 1, wherein said electric circuit is designed to selectively open and close said shunt circuit using a field-effect transistor.

9. A structural vibration damping device comprising:

a first piezoelectric element adapted to be mounted on a vibrating structure;

a shunt circuit inserted between two electrodes of said first piezoelectric element;

one or more second piezoelectric elements adapted to be mounted on said structure; and

an electric circuit for selectively opening and closing said shunt circuit, wherein;

said electric circuit is operable, when a voltage between two electrodes of said one or more second piezoelectric elements have a positive or negative extreme value, to close said shunt circuit so as to allow a current to flow between the electrodes of said first piezoelectric element, and, when said current is reduced to zero, to open said shunt circuit so as to preclude the current flow until a voltage between the electrodes of said one or more second piezoelectric elements subsequently have the extreme value; and

each of said shunt circuit and said electric circuit is designed to be operated using only a power generated by said first and second piezoelectric elements.

10. The structural vibration damping device as defined in claim 9, which is designed to allow a current flowing across said shunt circuit to pass through a coil.

11. The structural vibration damping device as defined in claims 9, wherein said electric circuit includes an extreme-value detection circuit using a peak hold circuit, and a circuit having a function of selectively opening and closing said shunt circuit in response to an output of said extreme-value detection circuit.

12. The structural vibration damping device as defined in claim 11, wherein said peak hold circuit includes a capacitor and a diode.

13. The structural vibration damping device as defined in claim 9, wherein said electric circuit includes an extreme-value detection circuit using a differentiation circuit, and a circuit having a function of selectively opening and closing said shunt circuit in response to an output of said extreme-value detection circuit.

14. The structural vibration damping device as defined in claim 13, wherein said differentiation circuit includes a capacitor and a resistor.

15. The structural vibration damping device as defined in claim 9, wherein said electric circuit is designed to selectively open and close said shunt circuit using a thyristor and a programmable unijunction transistor.

16. The structural vibration damping device as defined in claim 9, wherein said electric circuit is designed to selectively open and close said shunt circuit using a field-effect transistor.