Structural health monitoring system

Patent metadata

Field	Value
Publication number	US-11656201-B2
Application number	US-202017136615-A
Country	US
Kind code	B2
Filing date	Dec 29, 2020
Priority date	Mar 27, 2020
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

According to one implementation, a structural health monitoring system includes an ultrasonic transducer, an ultrasonic sensor, a strain sensor and a signal processing part. The ultrasonic transducer oscillates an ultrasonic wave to the first inspection area. The ultrasonic sensor detects a waveform of at least one of a transmission wave of the ultrasonic wave and a reflected wave of the ultrasonic wave. The transmission wave has transmitted the first inspection area. The reflected wave has been reflected in the first inspection area. The strain sensor detects a strain amount of the second inspection area. The signal processing part obtains at least one index, representing health of the structural object including the first inspection area and the second inspection area, based on the waveform detected by the ultrasonic sensor and the strain amount detected by the strain sensor.

First claim

What is claimed is:

1. A structural health monitoring system that monitors structural health of a structural object, the structural object including i) a first inspection area including no bent portion and ii) a second inspection area including a bent portion, the structural health monitoring system comprising:
an ultrasonic transducer that is attached to the first inspection area including no bent portion, and that oscillates and emits an ultrasonic wave toward the first inspection area;
an ultrasonic sensor that is attached to the first inspection area including no bent portion, and that detects a waveform of the ultrasonic wave emitted from the ultrasonic transducer, the waveform including at least one of i) a transmission wave of the ultrasonic wave having transmitted through the first inspection area and ii) a reflected wave of the ultrasonic wave having been reflected in the first inspection area;
a strain sensor that is attached to the second inspection area including the bent portion, and that detects a strain amount of the second inspection area without using the ultrasonic wave emitted from the ultrasonic transducer; and
signal processing circuitry that obtains at least one index, representing health of the structural object including the first inspection area and the second inspection area, based on i) the waveform detected by the ultrasonic sensor using the ultrasonic wave emitted from the ultrasonic transducer and ii) the strain amount detected by the strain sensor without using the ultrasonic wave emitted from the ultrasonic transducer.

2. The structural health monitoring system according to claim 1 , wherein the at least one index includes at least one of whether the structural object has been damaged, whether the structural object has cracked, whether the structural object made of fiber reinforced plastic has delaminated, and an index expressing degree of a defect that has arisen on the structural object.

3. The structural health monitoring system according to claim 2 , wherein the signal processing circuitry determines whether there is a possibility that the defect has arisen in the first inspection area, based on the detected strain amount in the second inspection area.

4. The structural health monitoring system according to claim 3 , wherein the signal processing circuitry segments the second inspection area into areas, and determines whether there is the possibility, based on the strain amount in a selected area out of the segmented areas, the selected area being closest to the first inspection area.

5. The structural health monitoring system according to claim 3 , further comprising:
a control circuit that controls the ultrasonic transducer to oscillate the ultrasonic wave toward the first inspection area when the signal processing circuitry has determined that there is the possibility.

6. The structural health monitoring system according to claim 1 , wherein the signal processing circuitry estimates an area in which a defect has arisen, based on the strain amount, when it has been determined that the defect has arisen in the first inspection area, based on the waveform.

7. An aircraft structural object comprising:
the structural health monitoring system according to claim 1 .

8. A method of monitoring the structural health of the structural object, the method comprising:
using the structural health monitoring system according to claim 1 .

9. A method of monitoring structural health of a structural object, the structural object including i) a first inspection area including no bent portion and ii) a second inspection area including a bent portion, the method comprising:
oscillating and emitting, using an ultrasonic transducer, an ultrasonic wave toward the first inspection area;
detecting, using an ultrasonic sensor, a waveform of the ultrasonic wave emitted from the ultrasonic transducer, the waveform including at least one of i) a transmission wave of the ultrasonic wave having transmitted through the first inspection area and ii) a reflected wave of the ultrasonic wave having been reflected in the first inspection area;
detecting, using a strain sensor, a strain amount of the second inspection area using the ultrasonic wave emitted from the ultrasonic transducer; and
obtaining an index, representing health of the structural object including the first inspection area and the second inspection area, based on i) the waveform detected by the ultrasonic sensor using the ultrasonic wave emitted from the ultrasonic transducer and ii) the strain amount detected by the strain sensor without using the ultrasonic wave emitted from the ultrasonic transducer.

10. The method according to claim 8 , wherein the structural object includes an aircraft structural object having a panel and at least one reinforcing member attached to the panel, the at least one reinforcing member including at least one of a stringer, a spar, a rib and a frame, the panel including the first inspection area, the at least one reinforcing member including the second inspection area, the strain sensor being attached to the at least one reinforcing member, the ultrasonic transducer and the ultrasonic sensor being attached to the panel.

11. The method according to claim 8 , wherein the ultrasonic wave is a Lamb wave.

12. The method according to claim 11 , wherein the first inspection area including no bent portion is larger than the second inspection area including the bent portion, the first and second inspection areas being determined based on a characteristic of a Lamb wave and a variation in the strain amount that the Lamb wave propagates in a wider range than a range in which the variation in the strain amount propagates while a first attenuation amount in amplitude of the Lamb wave is larger than a second attenuation amount of the variation in the strain amount in the bent portion.

13. The structural health monitoring system according to claim 4 , further comprising:
a control circuit that controls the ultrasonic transducer to oscillate the ultrasonic wave toward the first inspection area when the signal processing circuitry has determined that there is the possibility.

14. The structural health monitoring system according to claim 2 , wherein the signal processing circuitry estimates an area in which the defect has arisen, based on the strain amount, when it has been determined that the defect has arisen in the first inspection area, based on the waveform.

15. An aircraft structural object comprising:
the structural health monitoring system according to claim 2 .

16. An aircraft structural object comprising:
the structural health monitoring system according to claim 3 .

17. An aircraft structural object comprising:
the structural health monitoring system according to claim 4 .

18. The method according to claim 9 , wherein the structural object includes an aircraft structural object having a panel and at least one reinforcing member attached to the panel, the at least one reinforcing member including at least one of a stringer, a spar, a rib and a frame, the panel including the first inspection area, the at least one reinforcing member including the second inspection area, the strain sensor being attached to the at least one reinforcing member, the ultrasonic transducer and the ultrasonic sensor being attached to the panel.

19. The method according to claim 9 , wherein the ultrasonic wave is a Lamb wave.

20. The method according to claim 19 , wherein the first inspection area including no bent portion is larger than the

Assignees

• Subaru Corp

Inventors

• Soejima Hideki
• Nakano Takuya

Classifications

• G01N2291/0289

  Internal structure, e.g. defects, grain size, texture · CPC title

• B64D45/00

  Aircraft indicators or protectors not otherwise provided for · CPC title

• G01N29/11

  by measuring attenuation of acoustic waves · CPC title

• G01N29/041 Primary

  on the surface of the material, e.g. using Lamb, Rayleigh or shear waves · CPC title

• B64D2045/0085

  Devices for aircraft health monitoring, e.g. monitoring flutter or vibration · CPC title