US 12,153,036 B2
Estimation method
Yosuke Takeuchi, Musashino (JP); Takuya Kamisho, Musashino (JP); and Masayuki Tsuda, Musashino (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/431,571
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Feb. 6, 2020, PCT No. PCT/JP2020/004448
§ 371(c)(1), (2) Date Aug. 17, 2021,
PCT Pub. No. WO2020/170829, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 2019-028305 (JP), filed on Feb. 20, 2019.
Prior Publication US 2022/0137022 A1, May 5, 2022
Int. Cl. G01N 33/2045 (2019.01); G01N 17/00 (2006.01)
CPC G01N 33/2045 (2019.01) [G01N 17/006 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An estimation method for estimating when a fracture occurred in a metal material to thereby reduce a number of times that the metal material must be checked and to reduce the usage of sensing monitors in order to determine if a fracture has occurred, the method performed by an estimation apparatus, the method comprising:
(i) receiving input data including image data of a surface of the metal material and temperature information of an installation environment in which the metal material was installed;
(ii) transforming the image data of the surface of the metal material and the temperature information into a hydrogen embrittlement rate-temperature graph to thereby acquire a relationship between the image data and the temperature information;
(iii) calculating a fracture temperature of the metal material from a hydrogen embrittlement rate of the metal material based on the relationship between the image data and the temperature information;
(iv) calculating a period during which the fracture temperature was obtained as a fracture occurrence period of the metal material by using the temperature information;
(v) calculating a timing of when stress was applied to the metal material during the fracture occurrence period as a timing of when a fracture occurred in the metal material; and
(vi) renewing the metal material in the installation environment based on the timing of when the fracture occurred in the metal material,
wherein, in the step (v), outliers of the stress applied during the fracture occurrence period are detected using a predetermined outlier test method, and a period during which outliers are continuously detected is a period when higher stress was applied, and
wherein, in the step (v), periods during which outliers are continuously detected are ranked in descending order of period length when higher stress was applied, and the timing of when a fracture occurred in the metal material is also ranked according to the ranking of the periods during which outliers are continuously detected.