A construction of X-ray stress measurement using double exposure method

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04156
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Niigata University
• Principal Investigator: Suzuki Kenji 新潟大学, 人文社会科学系, 教授 (30154537)
• Co-Investigator(Kenkyū-buntansha): 城 鮎美 (瀬ノ内鮎美) 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 放射光科学研究センター, 主任研究員 (60707446)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: Ｘ線応力測定 / 粗大粒 / 溶接部 / 残留応力 / シンクロトロン放射光 / 中性子 / 二重露光法

Outline of Final Research Achievements

It is difficult to measure stresses of coarse grains and welded parts using X-rays. To solve this problem, we proposed a double exposure method using synchrotron high-energy X-rays and a CdTe pixel detector. This method was applied to the stress measurement of coarse grained materials and welded parts of austenitic stainless steel.
As a result, we were able to measure the bending strain of the beam with coarse grains. The bi-axial stress of the shrink-fitted ring could be measured. We were able to measure the residual stress distribution of the weld. Based on these results, we succeeded in measuring the residual stress map of the welding root of a butt-welded pipe (150A). Since the double exposure method uses X-rays transmitted through a flat plate, it was limited to the measurement of a plane stress. However, we proposed to create a detailed stress map together with the triaxial stress distribution by a neutron stress measurement.

Free Research Field

Ｘ線材料強度学

Academic Significance and Societal Importance of the Research Achievements

本研究の二重露光法により，これまでＸ線による応力測定が困難であった粗大粒や溶接部のＸ線応力測定が可能となり，歴史に残されていた難問が解決された意義は大きい．近年開発されたCdTeピクセル検出器により，高エネルギーＸ線の利用が可能となり，軽金属に限定されていた二重露光法を鉄鋼材料にも拡張した．このことは産業利用において大いに役立つ研究である．本研究の成果により，詳細な残留応力マップを作ることが可能となり，製造物の実応力解析の手法が確立した．本研究により実応力解析が可能となり，シミュレーションの結果を検定する方法が確立した意義は大きい．