著者

藤井 朋之 東郷 敬一郎 山本 崇博 鈴木 幸則 島村 佳伸 尾嶋 良文

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.62, no.12, pp.770-777, 2013-12-15 (Released:2013-12-20)

参考文献数

11

被引用文献数

4 5

---

In this paper, fatigue tests and finite element analysis are carried out on spot weld-bonded joints of mild steel (270MPa class) and ultra-high strength steel (980MPa class) in order to investigate influence of strength level of base steels on fatigue strength and fatigue fracture behavior of spot weld-bonded joints. From the fatigue tests and finite element analysis, the following results are obtained : (1) The fatigue strength of the spot weld-bonded specimen is higher than that of the spot welded specimen. (2) The fatigue limit of the spot weld-bonded specimens of the ultra-high strength steel is higher than that of the mild steel. (3) The interfacial debonding propagates from the adhesive edge to a nugget edge, and the fatigue crack initiates at the nugget edge in both steels. (4) The fatigue strength of spot weld-bonded specimens is improved because the stress concentration at the nugget edge is reduced by adhesive bonding during large part of fatigue life.

著者

島村 佳伸 麦島 新 轟 章

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.4, pp.133-140, 2008 (Released:2010-06-15)

参考文献数

15

被引用文献数

1

---

Moisture absorption affects mechanical properties of CFRP, thus monitoring of moisture absorption ration in CFRP is useful to assess the structural integrity. Besides, health monitoring of CFRP by using an electrical resistance change method has been investigated recently. In order to apply the electrical resistance change method to composite components in service, it is important to understand the effect of moisture absorption on the electrical resistance change. We have reported that the electrical impedance of CFRP increases not only in the transverse direction but also in the fiber. In order to investigate the effect of deformation constraint on the electrical impedance increase in the fiber direction, the electrical impedance changes of constrained and unconstrained CFRP specimens are measured at constant temperature and humidity. The results show that the electrical impedance change of the constrained specimen is much smaller than that of the unconstrained. The experimental results indicate that swelling in the transverse direction affects the electrical impedance in the fiber direction. The mechanism of electrical impedance change is discussed by using finite element analysis. The analytical results show that discrete contacts between carbon fibers and electrodes cause the electrical impedance change.

著者

三浦 祐太朗 藤井 朋之 東郷 敬一郎 島村 佳伸

出版者

一般社団法人 日本機械学会

雑誌

東海支部総会講演会講演論文集

巻号頁・発行日

vol.2014, pp._520-1_-_520-2_, 2014

著者

島村 佳伸 奥田 尚紀 東郷 敬一郎 荒木 弘安

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.56, no.5, pp.393-398, 2007

被引用文献数

7 7

---

It is well known that carbon nanofillers (CNFs) enhance the stiffness, electric conductivity and thermal conductivity of polymers. Alignment of carbon nanofillers in polymer is expected to increase the performances in the aligned direction. Several papers have reported that applying alternating electric field to a liquid suspension including CNFs causes alignment of CNFs in the electric field direction. Only a few papers have reported the fabrication of nanostructurally controlled composites by using AC field, but the conditions to let CNFs align have not been investigated. In this study, unidirectionally aligned carbon nanofiller/epoxy composite was fabricated under AC electric field, and the alignment of CNFs was in-situ observed during fabrication by using an optical microscope. Then, the effects of applied voltage, frequency and the weight fraction of CNFs on nanostructure were investigated. As a result, it is found that CNFs in uncured epoxy resin align in the AC electric field and form a chain-like network, and that in the end the network structure is hold with cured epoxy. It is also shown that the applied voltage and weight fraction affect the morphology of the network. Furthermore, the network morphology was quantified by using texture analysis. Local homogeneity in the longitudinal and transverse directions of the AC electric field was used. It is found that there is strong relationship between the changes of local homogeneity and network morphology.

著者

松崎 亮介 轟 章 島村 佳伸 小林 英男

出版者

一般社団法人日本機械学会

雑誌

日本機械学会関東支部総会講演会講演論文集

巻号頁・発行日

vol.2004, no.10, pp.205-206, 2004-03-03

---

Safety of automobiles is increasingly demanded. To prevent burst of tires, smart tires are currently under development The embedded sensor enables highly precise measurement of road surface friction, and the precise friction measurements make more efficient anti-blocking-system (ABS). In a previous study, the authors proposed a new wireless strain monitoring method that adopts the tire itself as a sensor, with an oscillator circuit. This method is very simple and useful, but it requires a battery to activate the oscillator circuit. In the present study, the previous method for wireless tire monitoring is improved to produce a passive wireless sensor. The capacitance change of tire causes changes of the tuning frequency. This change of the tuned radio wave enables us to measure the applied strain of the specimen wirelessly, without any power supply from outside. This new passive wireless method is applied to a specimen and the static applied strain is measured.

著者

上田 敏郎 島村 佳伸 東郷 敬一郎 藤井 朋之 岡島 いづみ 平松 正敬 佐古 猛

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.59, no.12, pp.964-969, 2010

被引用文献数

2 5

---

Carbon-fiber reinforced epoxy was decomposed using subcritical water and supercritical methanol to reclaim carbon fibers. The tensile strength of the reclaimed carbon fibers was measured. Then SEM observation, XPS, and Raman spectral analysis were conducted to elucidate the change of tensile strength caused by decomposition. The tensile strength decreased by 6% in the case of decomposition with supercritical methanol, and by 12~17% with subcritical water. The surfaces of reclaimed carbon fibers were resin-free. Decomposition did not affect the fiber surface and fracture surface morphology. Subsequent XPS analysis revealed that functional groups of the carbon fiber surface had been removed. Raman spectral analysis showed decreased graphitization of the carbon fiber surface. These results imply that the fracture toughness of the carbon fiber surface decreased because of breakage of carbon-carbon bonds in the carbon fibers as a result of decomposition.