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Volume 39 (2013)
- Issue 6 Pages 212-
- Issue 5 Pages 167-
- Issue 4 Pages 127-
- Issue 3 Pages 89-
- Issue 2 Pages 49-
- Issue 1 Pages 10-
Volume 39, Issue 5
Displaying 1-4 of 4 articles from this issue
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Research paper
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Satoshi ATOBE, Takeshi KITAGAWA, Ning HU, Hisao FUKUNAGA2013 Volume 39 Issue 5 Pages 167-175
Published: 2013
Released on J-STAGE: November 14, 2014
JOURNAL FREE ACCESSThis paper deals with the identification of multiple impact forces acting on FRP pressure vessels. The information to be identified are the locations and histories of the impact forces. In a previous paper (Journal of the Japan Society for Composite Meterials, Vol. 35, No. 3 (2009), pp. 106-111), multiple impact forces acting on a CFRP stiffened panel were experimentally identified by a method based on experimental transfer matrices which relate the impact forces and the responses of strain gauges. In the present paper, the identification method is applied to shell structures, i.e. FRP pressure vessels, and the effectiveness of the method is experimentally investigated. First, the validity of the experimental identification method is examined by identifying a single impact force. Then, the identification of multiple impact forces is performed. Here, the number of impact forces is set to two, and the impact forces are applied with impulse hammers of different impact tips in order to examine the effect of the impactor stiffness on the identification results. The results reveal the validity of the experimental identification method for shell structures. The identified locations and force histories are in good agreement with the measured ones, irrespective of the number of impact forces and the stiffness of the impactor.View full abstractDownload PDF (2167K) -
Shinichiro YAMASHITA, Isamu OHSAWA, Tsuyoshi MATSUO, Jun TAKAHASHI2013 Volume 39 Issue 5 Pages 176-183
Published: 2013
Released on J-STAGE: November 14, 2014
JOURNAL FREE ACCESSThe objective of this paper is to demonstrate the superiority in terms of soft skin effect of CF/PP. First, we defined soft skin effect as an ability to reduce stresses or forces, its rates, and vibration applied to human body by light impact. Next, drop weight impact test and FEM analysis were performed and following conclusions can be obtained. (1) In the case that human body collides with CF/PP products directly, the developed CF/PP shows high ability to reduce human’s pain and discomfort because of its surface softness and low inertia. (2) In the case that human body is protected by the CF/PP from impact loads of the colliding object, the new CF/PP shows high ability to reduce back face force and its speed because of its excellent damping property. Therefore, the soft skin effect of the developed CF/PP is superior to that of steel and aluminum. Such human friendly features of the CF/PP are useful to expand its applications.View full abstractDownload PDF (2338K) -
Eiichi HARA, Tomohiro YOKOZEKI, Hiroshi HATTA, Yutaka IWAHORI, Takashi ...2013 Volume 39 Issue 5 Pages 184-192
Published: 2013
Released on J-STAGE: November 14, 2014
JOURNAL FREE ACCESSTo propose a test method for the out-of-plane tensile modulus of laminated carbon fiber-reinforced plastics, 3-point bending tests using a laminated CFRP with the span direction coinciding with out-of-plane (through-the-thickness) direction were performed. It was demonstrated that the apparent bending modulus depends on the length of span to thickness ratio (L/t) and the tensile modulus E to shear modulus G ratio (E/G). Sensitivity analyses were performed to select the length of span to thickness ratio in order to evaluate the bending modulus near material modulus. Consequently, it is predicted that the bending modulus performed with the L/t＞25 bending specimen is equivalent to tensile modulus, if the apparent bending modulus were evaluated from 1 to 15 GPa, while modified equations for the out-of-plane modulus of QI-CFRP laminates obtained by three-dimensional laminate theory were also derived. This modification took stress condition in consideration of the small in-plane size like bending specimens into account. Moreover, it is demonstrated that apparent bending moduli were evaluated between upper- and lower-bound solutions. The upper-bound solution is an out-of-plane modulus based on existing three-dimensional laminate theory, and the other is modified out-of-plane modulus.View full abstractDownload PDF (1401K) -
Nobuhiro YOSHIKAWA, Tomotaka OGASAWARA, Howon LEE, Kojirou NAKAGAWA, J ...2013 Volume 39 Issue 5 Pages 193-198
Published: 2013
Released on J-STAGE: November 14, 2014
JOURNAL FREE ACCESSIn the cure process of fiber reinforced plastics accumulators, thermal spike due to exothermic reaction of the resin appears. It is necessary to accurately evaluate thermal spike for avoiding trial and error approach of temperature control for quality guarantee. We have developed a cure process simulator that is able to accurately evaluate the thermal spike of the thermosetting resin. Simplified meso-scale finite element model with definite separation of fiber and resin is used in the simulation. In this study, newly developed simulation system is examined through comparing with the experiment of cure process of fiber reinforced plastics accumulators.View full abstractDownload PDF (2770K)
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