M. M. Aish; E. H. Aish
Abstract
In this study the stress fields under uniaxial tension of the plane with arc cut were calculated. To describe the concentration of normal and shear stresses in the areas of the crack ends, new characteristics based on equilibrium conditions were introduced. The influence of the angle of the crack ...
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In this study the stress fields under uniaxial tension of the plane with arc cut were calculated. To describe the concentration of normal and shear stresses in the areas of the crack ends, new characteristics based on equilibrium conditions were introduced. The influence of the angle of the crack arc opening and the direction of the plane tension was studied. It was found that those factors changed the value and the stresses sign at the crack ends. The opening angles of arc cracks and tension direction promoting the development of cracks under the influence of tensile strain, tensile stresses or combination of the stresses were determined. The promoting conditions that inhibit the cracks were studied. Copyright © VBRI Press.
Masatoshi Shioya; Takashi Kajikawa; Kuniaki Takahashi; Yoshiki Sugimoto
Abstract
Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during ...
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Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during production process, is the matter of great concern. We have developed a method for determining this strength through the tensile test on a single fiber after introducing an artificial notch. In the present paper, this method has been refined. By using the refined method, the distribution of the maximum available tensile strength at various radial positions has been measured for a polyacrylonitrile-based carbon fiber. The difference between the maximum available tensile strength and the strength predicted using other methods such as those based on the fracture toughness and the fiber-length dependence of the tensile strength has also been discussed.
Heesup Choi; Masumi Inoue; Risa Sengoku; Hyeonggil Choi
Abstract
In this study, it is possible to disperse effectively cracked using synthetic fiber, an examination of the most suitable self-healing conditions was performed on the above crack width 0.1mm. As a result, effective crack dispersion using polyvinyl alcohol (PVA) fibers with polar OH - groups, as well as ...
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In this study, it is possible to disperse effectively cracked using synthetic fiber, an examination of the most suitable self-healing conditions was performed on the above crack width 0.1mm. As a result, effective crack dispersion using polyvinyl alcohol (PVA) fibers with polar OH - groups, as well as improved self-healing for cracks that are larger than 0.1 mm in width, posing concerns of CO2 gas and Cl - penetration, were observed. Also, CO3 2- reacts with Ca 2+ in the concrete crack, resulting in the precipitation of a carbonate compound, CaCO3. Based on this, it is deemed possible for the recovery of effective water tightness and strength recovery through effective freezing-thawing resistance to be made from cracks that are larger than 0.1 mm in width. In addition, it was determined that, as for the most suitable self-healing conditions in the inside and surface of the cracks, calcium hydroxide (Ca(OH)2) solution with CO2 micro-bubble was more effective in promoting the self-healing capability than water with CO2 micro-bubble.
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