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Volume 41 (2015)
- Issue 5 Pages 149-
- Issue 4 Pages 106-
- Issue 3 Pages 75-
- Issue 2 Pages 47-
- Issue 1 Pages 9-
Volume 41, Issue 1
Displaying 1-4 of 4 articles from this issue
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Research paper
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Damping Vibration Analysis of Composite Materials Using Mode Superposition and Homogenization MethodKazuyuki KOBAYASHI, Takao KOYAMA, Asumi SUGIMURA, Masahiro ARAI, Yoshi ...2015 Volume 41 Issue 1 Pages 9-18
Published: 2015
Released on J-STAGE: February 24, 2016
JOURNAL FREE ACCESSThis paper proposes a method for predicting modal damping ratios of a structure which consists of resin-based composite material with complex local structure using finite element analysis. If these modal damping ratios are given, a vibration analysis considering the frequency dependent structural damping can be achieved. However, it is difficult to estimate exactly the modal damping ratios by theoretical means. Therefore we proposed a method of identifying the damping ratios using numerical analysis based on the mathematical homogenization method. The natural frequencies and the mode shapes calculated by present analysis method were in good agreement with the results of the vibration measurement of particle-dispersed composite material plate. The calculated modal damping ratios, in terms of mode shape dependence and Vf dependence, had a good representation of the qualitative features of the experimental results. The magnitude of the calculated modal damping ratios, however, tend to be slightly greater than the experimental values.View full abstractDownload PDF (3983K) -
Tomohiro YOKOZEKI, Masaru ISHIBASHI, Yayoi KOBAYASHI, Hideyasu SHAMOTO ...2015 Volume 41 Issue 1 Pages 19-24
Published: 2015
Released on J-STAGE: February 24, 2016
JOURNAL FREE ACCESSPulsed laser surface treatment was applied to carbon fiber reinforced plastics (CFRPs) to enhance the work efficiency as well as to establish the stable clean process of surface treatment during the bonding process of CFRP structures. Surface analyses were conducted to CFRP treated by various laser conditions in order to find the optimal laser process. Adhesively bonded specimens were fabricated using CFRPs subjected to laser treatment, and adhesive strength of CFRPs bonded with adhesive films was evaluated compared with the abrasive paper treatment. Surface conditions, adhesive strength and adhesive fracture mode depended on the treatment parameters, and adhesive strength similar to abrasive paper treatment could be obtained in the specimens with appropriate laser treatment. It was concluded that laser surface treatment can be applied to the surface treatment process of CFRP bonded structures.View full abstractDownload PDF (2999K) -
Hideaki KATOGI, Kazunori UEMATSU, Yoshinobu SHIMAMURA, Keiichiro TOHGO ...2015 Volume 41 Issue 1 Pages 25-32
Published: 2015
Released on J-STAGE: February 24, 2016
JOURNAL FREE ACCESSIn order to apply natural fiber reinforced biomass plastics, i.e. green composites, to load-bearing structures, the fatigue property of natural fibers should be well understood. In this study, fatigue property and fatigue damage accumulation process of jute monofilament was investigated by conducting axial loading fatigue tests. Fatigue strength of each jute monofilament was determined by using a cross sectional area corresponding to the fracture portion. Fatigue strength of jute monofilament decreased with increasing the number of cycles to failure. The fatigue strength at 106 cycles was about 50% of the tensile strength. SEM observation of fiber surfaces showed that fatigue cracks occurred in elementary fibers at low cycles and the fatigue cracks propagated with increasing the number of cycles, while reduction of fiber stiffness was not found at low cycles. This implies that the fatigue cracks which were observed in the early stage nucleated and propagated only in the intercellular layers and/or primary wall and did not penetrate into the secondary walls of elementary fibers.View full abstractDownload PDF (4134K) -
Manato KANESAKI, Chika UCHIJO, Mototsugu TANAKA, Hiroshi SAITO, Masaak ...2015 Volume 41 Issue 1 Pages 33-44
Published: 2015
Released on J-STAGE: February 24, 2016
JOURNAL FREE ACCESSThe effect of repair using thermal fusion bonding (TFB) on residual compressive strength was investigated in carbon fiber reinforced polyamide 6 (CF/PA6) cross-ply laminate with several impact damage. Cross-ply laminates with different ply-thickness (0.04 mm and 0.12 mm) were prepared in order to investigate the influence of the different impact damage due to ply thickness. Here, cross-ply laminates used for specimens was made of CF/PA6 unidirectional semiprepreg, which had 54% in fiber volume fraction. The experimental results indicated that TFB was shown as one of the effective methods to repair the impact damage caused by matrix failure and to recover the compressive strength. In addition, fiber and matrix did not flow out from the specimen during TFB. On the other hand, TFB was not effective to decrease in compressive strength caused by fiber breakage due to buckling before reaching compressive strength of intact specimen.View full abstractDownload PDF (3526K)
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