著者

北川 正義 新濃 隆志 若生 豊

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.49, no.9, pp.970-975, 2000-09-15 (Released:2009-06-03)

参考文献数

9

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As one of serial studies on the mechanical properties of spider threads, the effect of viscid droplet on their deformation behavior was investigated. The viscid droplets are regularly spaced on the spiral thread building orb web for capturing insects. It was shown that 1) the most abundant amino acid of the droplet is prolyne, while the component of the capture thread is not so different from that of dragline, 2) its surface tension is about 65mN/m which is comparable to that of water, and 3) although the capture thread deforms like rubber due to the existence of the viscid droplet, it behaves like dragline if the droplets are removed from it.

著者

北川 正義

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.25, no.277, pp.979-983, 1976-10-15 (Released:2009-06-03)

参考文献数

15

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Craze and crack growth in polycarbonate, polyvinyl chloride and polymethyl methacrylate have been investigated under the presence of kerosene. The experiment for craze growth was carried out under the conditions of both constant rate loading and cyclic loading since the results under dead weight and step-wise loadings had previously been obtained. The delayed crack growth rate was investigated as a function of stress intensity factor.The experimental results were compared with the theoretical predictions derived from a model taking creep into account, which was proposed by the author.The results are summarized as follows.(1) The theory seems to hold also for the craze growth under constant rate and cyclic loadings.(2) The delayed crack growth may be classified in two types. One is the fibrous fracture type and the other is the quasi-brittle fracture type. The former type crack growth can be explained by the modified Knauss theory with the same time function as that of craze growth.