Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials)
Tensile tests were conducted for notched round-bar specimens to acquire the limit conditions of local failure, which is ductile failure after large local deformation for three types of steel, SGV480, SPV490 and SGV410, for nuclear containment structures. The notch deformation was monitored using a p...
| Main Authors: | , , |
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| Format: | Article |
| Language: | Japanese |
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The Japan Society of Mechanical Engineers
2023-09-01
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| Series: | Nihon Kikai Gakkai ronbunshu |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/transjsme/89/925/89_23-00046/_pdf/-char/en |
| _version_ | 1797669389092257792 |
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| author | Hitoshi NAKAMURA Kensaku ARAI Masaaki KIKUCHI |
| author_facet | Hitoshi NAKAMURA Kensaku ARAI Masaaki KIKUCHI |
| author_sort | Hitoshi NAKAMURA |
| collection | DOAJ |
| description | Tensile tests were conducted for notched round-bar specimens to acquire the limit conditions of local failure, which is ductile failure after large local deformation for three types of steel, SGV480, SPV490 and SGV410, for nuclear containment structures. The notch deformation was monitored using a profile projector. The notch’s cross-section radius and the curvature radius of the notched profile were continuously measured by image analysis in the tensile test. From those measurements, the stress and strain at the notch’s cross-section center were determined by Bridgman’s approximate solution and the elastoplastic FEM analysis. The true stress-true strain curve for the elastoplastic FEM was identified a priori by an optimization program that searches for the good curve in the exponential form applicable to large strain regions. No cracks were observed at the notch bottom surface in all specimens until the final rupture. The failure at the notch’s cross-section center was detected from the inflection point of the load-displacement curve. The limit strain diagrams were compared with those of ASME Sec. VIII-2 and its conservatism were discussed. Further, small-size notched round-bar specimens were sampled from the weld joints of SGV480 and SPV490 to determine the limit strain diagrams and true stress-true strain curves of the base metal, HAZ, and weld metal. The limit strain diagrams at each material of the weld joints were as high as or higher than the base metal, except for the weld metal of SPV490. The authors discussed the optical micrographs for fracture surfaces of specimens, the fracture morphology of weld joints, and the modified expression of a limit failure stress index regarded as the stress indication of the limit strain diagram in the high-stress triaxiality region. |
| first_indexed | 2024-03-11T20:43:38Z |
| format | Article |
| id | doaj.art-9f255dc11ccd4535925bb3acfae84667 |
| institution | Directory Open Access Journal |
| issn | 2187-9761 |
| language | Japanese |
| last_indexed | 2024-03-11T20:43:38Z |
| publishDate | 2023-09-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Nihon Kikai Gakkai ronbunshu |
| spelling | doaj.art-9f255dc11ccd4535925bb3acfae846672023-10-01T23:07:36ZjpnThe Japan Society of Mechanical EngineersNihon Kikai Gakkai ronbunshu2187-97612023-09-018992523-0004623-0004610.1299/transjsme.23-00046transjsmeLimit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials)Hitoshi NAKAMURA0Kensaku ARAI1Masaaki KIKUCHI2Center for creation of symbiosis society with risk, Yokohama National UniversityNuclear Regulation AuthorityNuclear Regulation AuthorityTensile tests were conducted for notched round-bar specimens to acquire the limit conditions of local failure, which is ductile failure after large local deformation for three types of steel, SGV480, SPV490 and SGV410, for nuclear containment structures. The notch deformation was monitored using a profile projector. The notch’s cross-section radius and the curvature radius of the notched profile were continuously measured by image analysis in the tensile test. From those measurements, the stress and strain at the notch’s cross-section center were determined by Bridgman’s approximate solution and the elastoplastic FEM analysis. The true stress-true strain curve for the elastoplastic FEM was identified a priori by an optimization program that searches for the good curve in the exponential form applicable to large strain regions. No cracks were observed at the notch bottom surface in all specimens until the final rupture. The failure at the notch’s cross-section center was detected from the inflection point of the load-displacement curve. The limit strain diagrams were compared with those of ASME Sec. VIII-2 and its conservatism were discussed. Further, small-size notched round-bar specimens were sampled from the weld joints of SGV480 and SPV490 to determine the limit strain diagrams and true stress-true strain curves of the base metal, HAZ, and weld metal. The limit strain diagrams at each material of the weld joints were as high as or higher than the base metal, except for the weld metal of SPV490. The authors discussed the optical micrographs for fracture surfaces of specimens, the fracture morphology of weld joints, and the modified expression of a limit failure stress index regarded as the stress indication of the limit strain diagram in the high-stress triaxiality region.https://www.jstage.jst.go.jp/article/transjsme/89/925/89_23-00046/_pdf/-char/enlocal failureductile fracturestress triaxialitylimit strainweld jointnuclear containment |
| spellingShingle | Hitoshi NAKAMURA Kensaku ARAI Masaaki KIKUCHI Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) Nihon Kikai Gakkai ronbunshu local failure ductile fracture stress triaxiality limit strain weld joint nuclear containment |
| title | Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) |
| title_full | Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) |
| title_fullStr | Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) |
| title_full_unstemmed | Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) |
| title_short | Limit conditions on local failure of nuclear containment steels (Notched round-bar tensile tests for base metals and weld joint materials) |
| title_sort | limit conditions on local failure of nuclear containment steels notched round bar tensile tests for base metals and weld joint materials |
| topic | local failure ductile fracture stress triaxiality limit strain weld joint nuclear containment |
| url | https://www.jstage.jst.go.jp/article/transjsme/89/925/89_23-00046/_pdf/-char/en |
| work_keys_str_mv | AT hitoshinakamura limitconditionsonlocalfailureofnuclearcontainmentsteelsnotchedroundbartensiletestsforbasemetalsandweldjointmaterials AT kensakuarai limitconditionsonlocalfailureofnuclearcontainmentsteelsnotchedroundbartensiletestsforbasemetalsandweldjointmaterials AT masaakikikuchi limitconditionsonlocalfailureofnuclearcontainmentsteelsnotchedroundbartensiletestsforbasemetalsandweldjointmaterials |