材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
66 巻 , 11 号
選択された号の論文の19件中1~19を表示しています
解説記事特集 日本の伝統を支える材料技術
解説
解説
  • 鈴木 茂雄
    2017 年 66 巻 11 号 p. 841-846
    発行日: 2017/11/15
    公開日: 2017/11/20
    ジャーナル フリー

    There are three elements, namely environment, material, and stress, as susceptibility conditions of damage patterns of the equipment. Susceptibility of damage can be mainly evaluated by temperature parameter. Damage patterns of the equipment become apparent in low temperature region, normal temperature region and high temperature region along with aging degradation, and these damage patterns cause leakage during operation. In particular, damage appears prominently under low temperature environment. Among them, it is difficult to extract susceptibility to external stress corrosion cracking External stress corrosion cracking of austenitic stainless steel is generated when grain boundary Cr depletion layer (sensitization) of weld heat affected zone (HAZ) occurs due to rainwater retention and sea salt particles. However, sensitization does not occur in all of HAZ. Occurrence of sensitization differs in every part. Therefore, this paper describes in detail findings obtained from survey results on the ESCC in a chemical plant.

論文
  • 飯塚 誠, 長岐 滋, 大下 賢一, 犾舘 俊光, 塚本 平
    2017 年 66 巻 11 号 p. 847-852
    発行日: 2017/11/15
    公開日: 2017/11/20
    ジャーナル フリー

    he effect of microscopic voids to macroscopic mechanical responce is interesting consideration, because ductile fracture is caused by the voids nucreation, growth and coalescence. So this study aims modeling of growth behavior of voids in ductile materials. Perforated sheets are deformed under uniaxial stress condition and progress of growth of holes are measured during examination. In order to represent variation of void shape and arrangement, damage tensor is employed. For the modeling of evolution of damage tensor and stress-strain relationship, anisotropic constitutive equation is presented. This equation is developed by incorporating damage tensor to Gurson’s yield function. Evolution equation is improved so that anisotropic growth of holes can be considered. The presented model shows good agreement for the measurement results using perforated sheet.

  • 倉橋 貴彦, 山際 健吾
    2017 年 66 巻 11 号 p. 853-860
    発行日: 2017/11/15
    公開日: 2017/11/20
    ジャーナル フリー

    In this paper, we present new unstructured triangular mesh generation method for singular stress field analysis of bonded structures based on finite element method. If tensile and bending loadings are applied to the bonded structure, stress concentration occurs around singular point. It is known that stress and strain distribution are proportional to r, i.e., r is distance from singular point and λ is order of singularity. In addition, in case of the stress analysis based on the FEM, it is known that the value of the stress component at singular point increases with decreasing mesh size around bonded structure. Therefore, fracture of the bonded structure evaluates by the intensity of stress singularity obtained by the stress distribution, and it is the most important that high accurate stress distribution is obtained. In this study, we introduce new mesh division procedure considering stress singularity near singular point, and some results for numerical experiments show in this paper.

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