著者

渡辺 圭子 日下 貴之 北條 正樹 福岡 俊康 石橋 正康

出版者

The Japan Society for Composite Materials

雑誌

日本複合材料学会誌 (ISSN:03852563)

巻号頁・発行日

vol.34, no.6, pp.226-232, 2008 (Released:2010-07-15)

参考文献数

22

被引用文献数

1 1

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The crack propagation behavior of CFRP laminates reinforced with Zanchor was experimentally investigated to find out the toughening mechanism under the mode II loading. The Zanchor is a novel technique of out-of-plane reinforcement to improve the interlaminar strength by entangling in-plane fibers in the through-thickness direction using special needles. Experimental result demonstrated that the effect of Zanchor process was remarkable for the improvement of mode II interlaminar fracture toughness of composite materials, where the fracture toughness proportionally increased with the Zanchor density. Moreover, broken traces of the fiber bundles oriented to the through-thickness direction were observed, whereas no fiber bridgings. Therefore, it was revealed that the key factor of the increase in mode II fracture toughness would be the breaking energy of fiber bundles, which was different from that under mode I loading.

著者

河原 康太 松田 直樹 北條 正樹 西川 雅章

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00582-16-00582, 2017 (Released:2017-05-25)

参考文献数

15

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Formulation based on the eigenfunction expansion is shown for second-harmonic generation simulations at a cylindrical interface. The displacement potentials of fundamental wave fields and second-harmonic fields are expressed as sums of eigenfunctions. The cylinder-matrix interface is assumed to be imperfect and modeled as a nonlinear spring interface for the purpose of considering roughness of the interface. Nonlinear equations in this model are dealt with the perturbation theory. The relational expression on the expansion coefficients of the fundamental waves and the second harmonics is shown. The results for the P wave incidence are demonstrated; although arbitrary incident wave field is available in the present method. As a result, both P and SV second harmonics are generated at the cylindrical interface. The numerical results for the directivity patterns of second harmonics are also given. The results show that the directivity patterns depend on the interfacial stiffness. Moreover the relationships between the interfacial stiffness and the ratio of stress in forward direction to backward direction are investigated in order to discuss the interfacial stiffness dependence in detail. The ratio significantly varies with the interfacial stiffness and the relationships are different by the frequency of the incident wave. Due to these characteristics, the ratio of stress in forward direction to backward direction can be useful for the evaluation of the interfacial stiffness. The influence of the ratio of the transverse stiffness to normal stiffness on the ratio of stress is also demonstrated. It is shown that the ratio of the interfacial stiffness has little effect on the ratio of stress.

著者

宮入 裕夫 北條 正樹

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.45, no.10, pp.1071-1077, 1996-10-15

被引用文献数

3 1