材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
66 巻 , 4 号
選択された号の論文の15件中1~15を表示しています
解説記事特集 宇宙応用の材料研究のこれまでとこれから
解説
論文
  • 真田 和昭, 陶山 丈順, 納所 泰華
    2017 年 66 巻 4 号 p. 299-305
    発行日: 2017/04/15
    公開日: 2017/04/20
    ジャーナル フリー

    This study examines interlaminar shear strength and self-healing of spread carbon fiber (SCF)/epoxy (EP) laminates.Self-healing is accomplished by incorporating a microencapsulated healing agent and catalyst within the epoxy matrix. Short beam shear specimens of self-healing SCF/EP laminates were prepared and tested. The healing efficiency was evaluated by the strain energies of virgin and healed specimens.The effects of spread width, stacking sequence and microcapsule concentration on the apparent interlaminar shear strength and healing efficiency are discussed.The damage area of the healed specimens was also examined by an optical microscope.

  • Vu Dung TRAN, Kimitaka UJI
    2017 年 66 巻 4 号 p. 306-311
    発行日: 2017/04/15
    公開日: 2017/04/20
    ジャーナル フリー

    The shear failure of reinforced concrete (RC) beams is extremely dangerous as it can occur suddenly and it is difficult to predict. Therefore, strengthening methods to prevent this failure in a RC beam are especially important. Recent years, CFRP material is promising alternatives for rehabilitation of deteriorated concrete members. In this study, it is assumed that, shear resistance of a RC beam decreases because of corroded stirrups, thus it need to be strengthened by using carbon fiber-reinforced polymer (CFRP) grid and sprayed mortar. Subsequently, the part where potentially appears diagonal crack in this beam would be taken out to analyze. The work of CFRP grid inside the mortar layer is modelled as a frame put on an elastic-brittle springs foundation. Simultaneously, bond behavior between mortar layer and substrate concrete is also modelled as the same type springs. A system of CFRP frame and springs is analyzed to investigate about the failure process and the influence of the strengthening layer. Lastly, case studies are presented by FEM analysis to compare with results of some previous tests. There is an appropriate good agreement between FEM and experimental approaches. It is suggested that the damage zone starts at the bottom of the specimen and spreads to the top during loading. In addition, the effect of CFRP and sprayed mortar on the resistance capacity of the structure was also clarified.

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