Non-destructive examination device

• US 5,612,495 A
• Filed: 10/06/1995
• Issued: 03/18/1997
• Est. Priority Date: 06/09/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hattori, Shinichi, Shimada, Takashi, Sakamoto, Takahiro, Egami, Noritaka, Taniguchi, Ryosuke
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/539,962
• Time in Patent Office: 529 Days
• Field of Search: 73/643, 73/579, 73/584, 73/596, 73/602, 73/627, 73/628, 73/577, 73/578
• US Class Current: 73/579
• CPC Class Codes: B06B 1/0284 with consecutive, i.e. sequential generation, e.g. with frequency sweep
• CPC Class Codes: B06B 2201/58 Magnetostrictive transducer
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 29/2412 using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]; investigating the presence of flaws using eddy currents G01N27/90, magnetostrictive transducers B06B1/08, measuring magnetostrictive properties G01R33/18
• CPC Class Codes: G01N 29/343 pulse waves, e.g. particular sequence of pulses, bursts

Abstract

A non-destructive examination device has an excitation current generation device for supplying an excitation current based on a control signal from a control device, a vibration excitor device for generating an elastic wave in accordance with athe excitation current and for vibrating an examination target to be examined by using the elastic wave; a response detection device (an acceleration sensor) for detecting a response of the vibration of the examination target caused by the elastic wave and for processing the response data in order to select desired examination information. The excitation current generation device generates the excitation current of an alternating pulse wave such as a pulse wave, or a rectangular wave, or a triangular wave, or a sine wave based on the control signal which is also a pulse signal. It can be acceptable to incorporate a plurality of the vibration excitor devices on the examination target in the non-destructive examination device.

Claims

1. A non-destructive examination device, comprising:

excitation current generation means for generating an excitation current and supplying said excitation current;

control means for generating a control signal to control operation of said excitation current generation means and for transmitting said control signal to said excitation generation means;

vibration excitor means for receiving said excitation current and for generating an elastic wave in accordance with a magnitude of said excitation current and for vibrating an examination target to be examined by using said elastic wave;

response detection means for detecting a vibration of said examination target responding to said elastic wave and for transforming said vibration to an electrical signal and for providing said electrical signal;

signal processing means for receiving said electrical signal and for processing said electrical signal in order to obtain desired examination information; and

amplifier means located between said excitation current generation means and said vibration excitor means for amplifying said excitation current and for generating an excitation current having a desired magnitude, and for providing said amplified excitation current to said vibration excitor means;

wherein said signal processing means receives said excitation current generated by said excitation current generation means, and adds and averages said electrical signal provided from the response detection means at a constant timing rate in accordance with the vibration of said vibration excitor means imparted to said examination target, based on a trigger generated when said excitation current is detected.

2. A non-destructive examination device as claimed in claim 1, wherein

said excitation current generation means provides said excitation current of a pulse phase to said vibration excitor means in accordance with said control signal.

3. A non-destructive examination device as claimed in claim 1, wherein

said excitation current generation means provides said excitation current of a sine wave phase to said vibration excitor means in accordance with said control signal.

4. A non-destructive examination device as claimed in claim 1, wherein

said excitation current generation means provides said excitation current of a rectangular wave phase to said vibration excitor means in accordance with said control signal.

5. A non-destructive examination device as claimed in claim 1, wherein

said excitation current generation means provides said excitation current of a triangular wave phase to said vibration excitor means in accordance with said control signal.

6. A non-destructive examination device as claimed in claim 1, wherein

said vibration excitor means comprises a plurality of vibration excitor devices which have a same configuration and a same function, said excitation current generation means provides said excitation current to said plurality of vibration excitor devices, said plurality of vibration excitor devices receives said excitation current in synchronization with each other, and each of said plurality of vibration excitor devices generates said elastic wave in accordance with said excitation current.

7. A non-destructive examination device as claimed in claim 6, further comprises a plurality of amplifier means located between said excitation current generation means and said plurality of vibration excitor devices, each of said plurality of amplifier means connected to one of said plurality of vibration excitor devices, said plurality of amplifier means amplifying said excitation current and each of said plurality of amplifier means generating an excitation current having a desired magnitude and providing said amplified excitation current to one of said plurality of vibration excitor devices.

8. A non-destructive examination device as claimed in claim 1, wherein

said vibration excitor means comprises a magneto striction vibrator having a hollow body and an excitation coil wound around said hollow body, and said magneto striction vibrator vibrates when said excitation current flows in said excitation coil.

9. A non-destructive examination device as claimed in claim 8, wherein

a resonant frequency of said excitation current flowing through said excitation coil is determined by a propagation speed of said vibration propagated in said magneto striction vibrator and a shape of said magneto striction vibrator.

10. A non-destructive examination device as claimed in claim 9, wherein

a full length of said magneto striction vibrator is a multiple of a 1/4 wavelength of said resonant frequency.

11. A non-destructive examination device as claimed in claim 8, wherein

said magneto striction vibrator having a laminate structure comprises a plurality of thin plates of a magneto striction material, and a laminate direction of said plurality of thin plates of said magneto striction vibrator and a vibration direction of said magneto striction vibrator cross at right angles.

12. A non-destructive examination device as claimed in claim 11, wherein

said magneto striction vibrator has a laminate structure comprises a plurality of thin plates of a magneto striction material of Nickel (Ni).

13. A non-destructive examination device as claimed in claim 11, wherein

said magneto striction vibrator has a laminate structure comprises a plurality of thin plates of a magneto striction material of Cobalt-Iron (Co-Fe).

14. A non-destructive examination device as claimed in claim 1, wherein

the magnitude and the frequency of said excitation current is changed by said control signal generated by said control means.

15. A non-destructive examination device, comprising:

excitation current generation means for generating an excitation current and supplying said excitation current;

control means for generating a control signal to control operation of said excitation current generation means and for transmitting said control signal to said excitation generation means;

vibration excitor means for receiving said excitation current and for generating an elastic wave in accordance with a magnitude of said excitation current and for vibrating an examination target to be examined by using said elastic wave;

response detection means for detecting a vibration of said examination target responding to said elastic wave and for transforming said vibration to an electrical signal and for providing said electrical signal;

signal processing means for receiving said electrical signal and for processing said electrical signal in order to obtain desired examination information; and

said signal processing means receives said excitation current generated by said excitation current generation means, and adds and averages said electrical signal provided from the response detection means at a constant timing rate in accordance with the vibration of said vibration excitor means imparted to said examination target, based on a trigger generated when said excitation current is detected.