著者

坂本 潤嗣 藤井 雅留太 中村 正行

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.14, no.4, pp.257-263, 2014-12-28 (Released:2014-12-28)

参考文献数

21

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This paper presents a new and convenient process for determining the material plasticity parameters of metal materials through an indentation test conducted using a Rockwell testing machine and FE analysis. Identified parameters almost coincide with practical values. The proposed method can be used to evaluate the characteristics of materials on the order of micro to millimeters. First, the P-h curves of the indentation are determined by experiment. Second, FE analysis of the indentation test assuming plastic hardening behavior in power-law hardening material is specified by the stress-strain curve. The FE model consisted of the test piece material and the indenter with a spring element considered the elastic deformation of the measuring system. The material parameters can be identified based on the curve fit using the polynomial function consisting of material parameters. The best solution is determined by using the response surface methodology. For identification example using steel and cupper alloy, the estimation of the plastic and elastic properties are possible for practical use.

著者

Kenji KATOH Tatsuro WAKIMOTO

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.14, no.Special_Issue, pp.s36-s41, 2014-07-01 (Released:2014-09-03)

参考文献数

10

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It is well known as the wringing phenomenon of gage blocks that a strong adhesive force appears between two smooth surfaces when a thin liquid film is applied on the interface. A theoretical and experimental study is conducted to discuss the wringing mechanism. The liquid film may be separated into a large number of small puddles when two surfaces are rubbed together. One can expect a large adhesive force due to the resultant of surface tension acting on the circumference of each puddle. Numerical results for oil distribution between two surfaces show that the total perimeter length of liquid film reaches 10500 m on the surface of 3cm2, which leads to 1.0×106 (N/m2) for the adhesive force. The adhesive forces measured experimentally roughly agree with the theoretical value. A simple model is proposed to explain the adhesive force dependence on the velocity of pulling apart two surfaces.

著者

森 幸治 藤川 祐介 松原 裕樹 堀口 佑樹

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.4, pp.360-365, 2013-12-28 (Released:2014-03-28)

参考文献数

3

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In order to produce bio-diesel fuel (BDF) effectively from triglyceride contained in coffee grounds, the solid catalyst method using calcium oxide was examined. Since commercially available calcium oxide has low catalytic activity, a method of converting the calcium oxide to calcium methoxide and/or calcium glyceroxide before esterification was tested. The method was applied to generate the BDF from unused canola oil. The produced liquid was analyzed both chemically and by the NMR, and it was revealed that the liquid was able to be called as BDF and esterification rate was about 80%. Extraction of triglyceride from waste coffee grounds was tried using hexane as a solvent, and 780 mL of triglyceride-rich oil was extracted from 8 kg of the waste coffee grounds. The oil was subjected to the BDF production using the calcium oxide and the BDF was produced at the esterification rate of about 75%. The coffee grounds after the extraction of the triglyceride-rich oil were applied to deodorants and solid fuels. The experimental results showed that the coffee grounds decreased the smell of cigarettes. Furthermore, it was also found that the coffee grounds were easily ignited and burned by adding some sawdust and wax to the coffee grounds.

著者

森田 康之 石黒 孝知 巨 陽

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.1, pp.88-92, 2013-03-28 (Released:2013-09-28)

参考文献数

20

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High-efficiency technology to the photodiodes has become a critical issue. Surface plasmon resonance (SPR) would be one of the means for solving the problem. Photocurrent of photodiodes is enhanced by metal nanoparticles, which induce the localized SPR, deposited on light-receiving surface of the photodiodes. Most previous studies had been focused on the photocurrent enhancement effect around maximum absorption wavelength of the nanoparticles. The effect except the wavelength has not been paid attention yet. For instance, in case of a solar cell, metal nanoparticles which have maximum absorption wavelength at around 500nm, have been widely employed since solar light has higher illuminance around 500nm. However, the photocurrent enhancement effect of the nanoparticles has not studied around near-infrared light though illuminance of the near-infrared light is quite valuable. Therefore, in this study, experimental investigation of photocurrent enhancement effect was conducted using Au nanoparticles with 100 and 150nm in nominal diameters, which have maximum absorption wavelengths at around 500nm. As a result, the photocurrent enhancement effect was obtained at near-infrared wavelengths. In addition, higher enhancement effect was achieved when the two Au nanoparticles were mixed. This would be ascribable to obtaining wider bandwidth of maximum absorption wavelengths due to mixing of different-size nanoparticles.

著者

小笠原 永久 千葉 矩正 山田 浩之 Xi CHEN

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.12, no.1, pp.26-32, 2012-03-28 (Released:2012-09-28)

参考文献数

13

被引用文献数

1

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An identification method with a sharp indentation for elastoplastic properties of film/substrate system is proposed. The method is based on extensive finite element computation on "soft film on hard substrate" cases indented with a sharp indenter. The method utilizes the substrate effect on load versus displacement relation in the indentation; this effect has often been regarded as undesirable. The computational results are expressed as response surfaces in a material parameter space. Based on the surfaces, and employing experimentally obtained load versus displacement relation, the elastoplastic properties of the film are identified. To determine the elastoplastic properties more accurately, it is important to use not only the loading curve but also the unloading curve. Numerical examples determined by this method for film/substrate system are given.

著者

高橋 明宏 山元 直行 豊廣 利信

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.15, no.1, pp.38-44, 2015-04-13 (Released:2015-04-13)

参考文献数

21

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The Shielded metal arc welding is mostly popular for fused injection method of metal to metal. The spatter particle of various sizes appears during the metal arc welding, and then adheres so strongly on the surface of welded plate. In general, the commercial spatter adhesion preventive agent is coated on the surface of plate before welding. However, the agent from artificial organic synthesis has several problem, such as influence of global environmental and human health, stink and expensive. The purpose of this study is to develop the new welding spatter adhesion preventive agent made of water, flour powder and honey, which brings the environmental merit, no stink and low cost. Effective contents among water, flour and honey was confirmed by sensory evaluation test and experimental observation after welding. The results of tensile inspection test of a butt welded specimen of SS400 and hydrogen analysis by JIS Z3118 satisfied welded strength and the reliability of welding. Anti-adhesive mechanism was discussed based on heat characteristics and observation of boundary between spatter and surface of welded plate. Another combinations as grain or starch powder and syrup with spatter anti-adhesive effect were also described.

著者

Daisuke MORIOKA Ichiro KITAYAMA Kosuke NAKANO Masato KITANO Takashi YAMANAKA Hideyo KOYAMA Takashi MORIMOTO Hideki SONOBE Noriyuki MIYAZAKI

出版者

The Japanese Society for Experimental Mechanics

雑誌

Advanced Experimental Mechanics (ISSN:21894752)

巻号頁・発行日

vol.1, pp.269-276, 2016-08-31 (Released:2017-02-06)

参考文献数

10

被引用文献数

1

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The purpose of this study was to quantitatively analyze the stress and deformation that occur in plastic ankle-foot orthoses (PAFOs) during walking after it is trimmed. First, PAFOs with incorporated sensors were individually prepared for 2 patients with hemiplegia. Mechanical data were then obtained while individuals wore the PAFOs during walking. Here we report the results of mechanical data and finite element analysis of trimmed plastic ankle-foot orthoses worn by two patients with left-hemiplegia. The results could provide prosthetists with some suggestions for forming orthoses.

著者

Khine Tun NAUNG Rei MIKOSHIBA Junhyuk LEE Hideaki MONJI

出版者

The Japanese Society for Experimental Mechanics

雑誌

Advanced Experimental Mechanics (ISSN:21894752)

巻号頁・発行日

vol.1, pp.80-85, 2016-08-31 (Released:2017-02-06)

参考文献数

4

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The aim of the study is to examine the effect of the amount of the dissolved gas on the two phase flow and to examine the acceleration of bubble generation on two-phase nozzle flow by modifying the shape of orifice plate. In the experiment, the molar concentration of CO2 gas was changed at the dissolution process. As increasing the CO2 molar concentration, the void fraction increased and the liquid velocity decreased at the throat. On the other hand, the bubble velocity was almost constant when dissolved gas rate was changed. Therefore, the slip velocity between the bubble and the liquid increased. Moreover, the amount of bubble is different by changing the hole type of orifice plate such as different holes diameter and respective cross section area for each plate. In case of the orifice of seven holes, it cannot reach the sound speed at the throat but it is closest to the sound speed in the case of other orifices.

著者

相澤 孝司 菅野 昭

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.1, pp.67-73, 2013-03-28 (Released:2013-09-28)

参考文献数

12

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The main role of conventional safety helmets is to protect the human head from external forces. So far the design of standardized helmets has placed an excessive emphasis on mechanical performance from this standpoint. During wearing the helmets, users experience high temperature rise in the head as well as excessive perspiration and an oppressive feeling. These discomforts prevent users from wearing the helmets. Behavior of air flow around the helmets needs to be studied in order to examine air cooling effects while users wear the helmets. Several techniques such as smoke wire, tuft and smoke injection methods have been applied to visualize air flows around the helmets which a mannequin wears in a low-velocity type wind tunnel. The pressure distributions on the outer surfaces of the helmets are measured on pressure transducers using diffusion type semiconductors. The stream lines and pressure distributions on the outer surfaces of the helmets are clarified by the present experiments. It is expected that the helmets are designed more rationally based on both fluid mechanics and the present experimental data.

著者

大 久 保 努 高 橋 優 信 久 保 田 健 吾 原 田 秀 樹 時 田 政 輝 上 村 繁 樹 前 野 一 夫

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.15, no.1, pp.30-37, 2015

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Down-flow hanging sponge (DHS) reactor has been developed mainly for sewage treatment in developing countries. The novel rector employs polyurethane sponge material as support media, which promises a proliferation of a large amount of biomass, and thus an excellent capability of removing pollutants. The characterization of the three types of sponge support media is conducted in respect of water flow and oxygen uptake ability. Water was supplied to the device which consisted of 40 sponge media connected in series, and then tracer experiment was carried out. The ratios of actual hydraulic retention time (HRT) per theoretical HRT were in the range of 25-67% depending on the type of support media, meaning that short circuit flow occurs in this type of reactor. By supplying deoxygenized water from the top of the device, overall volumetric oxygen transfer coefficient, K_La, was evaluated. In spite of the non-aerated conditions, the K_La values were so high, 0.56-4.88 (1/min), surpassing those of other mechanically aerated aerobic processes. Furthermore, it was found that the suspended solids (SS) concentration in the influent played a role to increase the ratio of actual HRT/theoretical HRT, meaning that management of the influent SS concentration is prerequisite for preventing the clogging problem in the DHS.