報告書番号

T97034

タイトル（和文）

改良９Ｃｒ－１Ｍｏ鋼の非弾性構成式の開発第３報：等温および温度変動下繰返し変形への拡張

タイトル（英文）

DEVELOPMENT OF INELASTIC CONSTITUTIVE EQUATIONS FOR MODIFIED 9CR-1MO STEEL (3RD REPORT: EXTENSION OF THE CONSTITUTIVE MODEL FOR CYCLIC DEFORMATION UNDER ISOTHERMAL AND NONISOTHERMAL CONDITIONS)

概要 （図表や脚注は「報告書全文」に掲載しております）

本報では前報にて提案した非弾性構成式モデルの等温および温度変動下繰返し変形への拡張について検討した。改良９Ｃｒ－１Ｍｏ鋼を用いて等温繰返し変形試験を行った結果，本材は２００～６００度において顕著な繰返し軟化挙動を示すことが明らかとなった。また，各種の温度変動試験を行った結果，繰返し変形に及ぼす温度履歴の影響は比較的小さいことが分かった。本試験結果に基づき，非弾性構成式モデルを温度変動繰返し変形下へと拡張した。本モデルを様々な等温単調負荷，ひずみ保持も含む等温繰返し変形および温度変動を伴う繰返し変形に適用した結果，何れの場合もほぼ満足すべき精度で応力ひずみ応答がシミュレートされることが確認された。

概要 （英文）

A SERIES OF CYCLIC DEFORMATION TESTS WAS CONDUCTED ON MODIFIED 9CR-1MO STEEL AT VARIOUS TEMPERATURES, INCLUDING NONISOTHERMAL CONDITIONS TO INVESTIGATE INELASTIC BEHAVIOR OF THE MATERIAL. THE MATERIAL SHOWED CYCLIC SOFTENING BEHAVIOR UNDER TEMPERATURES BETWEEN 200 DEGREE AND 600 DEGREE, AND ITS DEGREE GOT LARGER AS THE TEMPERATURE WAS INCREASED. AS FOR A DEPENDENCY OF CYCLIC RESPONSE ON TEMPERATURE VARIATIONS, IT SEEMED THAT IT WAS RELATIVELY SMALL IN THE STEEL. BASED ON THE TEST RESULTS, THE UNIFIED CONSTITUTIVE MODEL PROPOSED IN THE PREVIOUS REPORT WAS EXTENDED FOR CYCLIC DEFORMATIONS, INCLUDING UNDER NONISOTHERMAL CONDITIONS. TO EVALUATE THE VALIDITY OF THE CONSTITUTIVE MODEL, IT WAS APPLIED TO ANALYSIS OF INELASTIC BEHAVIOR UNDER MONONOTIC TENSION, STRESS RELAXATION, CREEP, ISOTHERMAL CYCLIC DEFORMATIONS INCLUDING STRESS RELAXATION AND NONISOTHERMAL CYCLIC DEFORMATIONS. IT WAS FOUND THAT THE PRESENT CONSTITUTIVE MODEL WAS SUCCESSFUL IN DESCRIBING THE INELASTIC BEHAVIOR OF THE STEEL ADEQUATELY.

報告者

キーワード