US 12,306,097 B2
Residual stress estimation apparatus and method
Eun Jeong Choi, Seongnam-si (KR); Keum Hyang Lee, Hwaseong-si (KR); Min Chul Shin, Seoul (KR); Chan Ho Jeong, Hwaseong-si (KR); Lae Hyong Kang, Jeonju-si (KR); Hye Lim Jang, Iksan-si (KR); and Dae Hyun Han, Gunsan-si (KR)
Assigned to Hyundai Motor Company, Seoul (KR); Kia Corporation, Seoul (KR); and Industrial Cooperation Foundation Jeonbuk National University, Jeonju-si (KR)
Filed by Hyundai Motor Company, Seoul (KR); Kia Corporation, Seoul (KR); and INDUSTRIAL COOPERATION FOUNDATION JEONBUK NATIONAL UNIVERSITY, Jeonju-si (KR)
Filed on Dec. 5, 2022, as Appl. No. 18/075,160.
Claims priority of application No. 10-2022-0082347 (KR), filed on Jul. 5, 2022.
Prior Publication US 2024/0011902 A1, Jan. 11, 2024
Int. Cl. G01N 21/88 (2006.01); G01N 21/3563 (2014.01); G01N 21/3586 (2014.01); G02B 5/30 (2006.01)
CPC G01N 21/3586 (2013.01) [G01N 21/3563 (2013.01); G02B 5/30 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An apparatus for estimating residual stress, comprising:
an inspection unit comprising:
a generator configured to generate and emit a first terahertz wave to a subject to be inspected,
a detector configured to receive the first terahertz wave emitted from the generator and to detect a second terahertz wave that is transmitted through or reflected from the subject,
a first polarizer disposed downstream relative to the generator in a first propagation direction of the first terahertz wave, and
a second polarizer disposed upstream relative to the detector in a second propagation direction of the second terahertz wave; and
a controller configured to estimate the residual stress of the subject based on the first terahertz wave and the second terahertz wave,
wherein the inspection unit is configured to:
rotate the first polarizer and the second polarizer, and
detect a set of terahertz waves detected based on rotating the first polarizer and the second polarizer by an increment of an angle within an angular range while maintaining the first polarizer and the second polarizer to be orthogonal to each other.