Pressure testing method and pressure tester

Patent metadata

Field	Value
Publication number	US-2021301980-A1
Application number	US-202117217130-A
Country	US
Kind code	A1
Filing date	Mar 30, 2021
Priority date	Mar 31, 2020
Publication date	Sep 30, 2021
Grant date	—

Abstract

Provided is a pressure testing method for a high-pressure tank capable of avoiding a destruction of the high-pressure tank during a pressure test. A pressure testing method includes: extracting a plurality of AE waveforms from output waveforms of an AE sensor while increasing a pressure inside the high-pressure tank; and testing the high-pressure tank based on the extracted plurality of AE waveforms. The method includes: while increasing the pressure inside the high-pressure tank, classifying the extracted AE waveforms into first waveforms and second waveforms with a classifier that is machine-learned so as to classify the plurality of AE waveforms into the first waveforms derived from a macrocrack that increases immediately before destruction of the high-pressure tank, and the second waveforms derived from a microcrack smaller than the macrocrack; and stopping pressurization of the high-pressure tank based on the number of the first waveforms.

First claim

What is claimed is:

1 . A pressure testing method for a high-pressure tank including a liner having an outer surface and a fiber-reinforced resin layer covering the outer surface of the liner, the method comprising: extracting a plurality of AE waveforms from an output waveform of an AE sensor, the AE sensor being configured to detect AE waves generated in the high-pressure tank while increasing a pressure inside the high-pressure tank; and testing the high-pressure tank based on the extracted plurality of AE waveforms, the method further comprising:
while increasing the pressure inside the high-pressure tank, classifying the extracted plurality of AE waveforms into first waveforms and second waveforms with a classifier that is machine-learned so as to classify the plurality of AE waveforms into the first waveforms derived from a macrocrack that increases immediately before destruction of the high-pressure tank, and the second waveforms derived from a microcrack smaller than the macrocrack; counting the number of the first waveforms classified, and stopping pressurization of the high-pressure tank based on the number of the first waveforms counted.

2 . The pressure testing method according to claim 1 , wherein in response to the cumulative number of the first waveforms reaching equal to or greater than a first threshold, the method stops pressurization of the high-pressure tank.

3 . The pressure testing method according to claim 1 , wherein in response to an increasing rate of the first waveforms to an increase amount of pressure in the high-pressure tank being equal to or greater than a second threshold, the method stops pressurization of the high-pressure tank.

4 . The pressure testing method according to claim 1 , wherein in response to a ratio of the first waveforms to a sum of the first waveforms and the second waveforms increasing equal to or greater than a third threshold, the method stops pressurization of the high-pressure tank.

5 . The pressure testing method according to claim 1 , wherein the high-pressure tank is filled with liquid for pressurizing the inside of the high-pressure tank.

6 . The pressure testing method according to claim 1 , wherein the high-pressure tank is filled with gas for pressurizing the inside of the high-pressure tank.

7 . The pressure testing method according to claim 1 , wherein
the method wavelet-transforms the extracted plurality of AE waveforms to create a plurality of images while increasing the pressure inside the high-pressure tank, classifies the plurality of images corresponding to the plurality of AE waves into first images corresponding to the first waveforms and second images corresponding to second waveforms with the classifier that is machine-learned so as to classify the first images and the second images; counts the number of the first images classified; and stops pressurization of the high-pressure tank based on the number of the first images counted.

8 . A pressure tester configured to test a high-pressure tank including a liner having an outer surface and a fiber-reinforced resin layer covering the outer surface of the liner, the pressure tester being configured to extract a plurality of AE waveforms from an output waveform of an AE sensor, the AE sensor being configured to detect AE waves generated in the high-pressure tank while increasing a pressure inside the high-pressure tank; and test the high-pressure tank based on the extracted plurality of AE waveforms,
the pressure tester comprising a controller configured to control pressurization of an inside of the high-pressure tank, the controller comprising: a pressurizing unit configured to execute pressurization of the inside of the high-pressure tank; a classifier that is machine-learned so as to classify the plurality of AE waveforms into first waveforms derived from macrocracks that increase immediately before destruction of the high-pressure tank, and second waveforms derived from microcracks smaller than the macrocracks; a counter configured to, while increasing the pressure inside the high-pressure tank by the pressurizing unit, count the number of the first waveforms classified by the classifier; and a pressurization stopper configured to stop pressurization of the high-pressure tank by the pressurizing unit based on the number of the first waveforms counted by the counter.

9 . The pressure tester according to claim 8 , wherein in response to the cumulative number of the first waveforms reaching equal to or greater than a first threshold, the pressurization stopper stops pressurization of the high-pressure tank.

10 . The pressure tester according to claim 8 , wherein in response to an increasing rate of the first waveforms to an increase amount of pressure in the high-pressure tank being equal to or greater than a second threshold, the pressurization stopper stops pressurization of the high-pressure tank.

11 . The pressure tester according to claim 8 , wherein in response to a ratio of the first waveforms to a sum of the first waveforms and the second waveforms increasing equal to or greater than a third threshold, the pressurization stopper stops pressurization of the high-pressure tank.

12 . The pressure tester according to claim 8 , wherein the pressurizing unit pressurizes the inside of the high-pressure tank with a pump configured to fill the high-pressure tank with liquid.

13 . The pressure tester according to claim 8 , wherein the pressurizing unit pressurizes the inside of the high-pressure tank with a pump configured to fill the high-pressure tank with gas.

14 . The pressure tester according to claim 8 , wherein the controller further includes: an extractor configured to extract a plurality of AE waveforms from an output waveform of the AE sensor; and a converter configured to wavelet-transform the plurality of AE waveforms extracted by the extractor to generate a plurality of images,
the classifier is machine-learned so as to classify the plurality of images corresponding to the plurality of AE waves into first images corresponding to the first waveforms and second images corresponding to second waveforms, the extractor is configured to extract a plurality of AE waveforms from the output waveforms of the AE sensor while increasing the pressure inside the high-pressure tank, the converter is configured to wavelet-transform the plurality of AE waveforms extracted by the extractor to create a plurality of images, the classifier is configured to classify the plurality of images converted by the converter into the first images and the second images, the counter is configured to count the number of the first images classified by classifier, and the pressurization stopper is configured to stop pressurization of the high-pressure tank based on the number of the first images counted by the counter.

Assignees

• Toyota Motor Co Ltd

Inventors

• Hori Yoshihiro
• Doi Takayoshi

Classifications

• F17C2203/0636

  Metals · CPC title

• F17C2205/0397

  on both sides of the pressure vessel · CPC title

• F17C2203/0604

  Liners · CPC title

• F17C2223/0123

  gaseous, e.g. CNG, GNC · CPC title

• F17C2223/036

  Very high pressure (>80 bar) · CPC title