著者

東海林 一 水谷 義弘 葭田 貴子

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.84, no.858, pp.17-00452-17-00452, 2018 (Released:2018-02-25)

参考文献数

10

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Generally in Japan, high skilled UT engineer performed examination and high reliability of examination results are achieved. However, it is not confirmed how high skill and actual probability of detection (POD). In the performance demonstration (PD) system in US, there are determined that the number of defect, minimum number of detection, number of unflawed area and allowable false detection, but it is not considered the defect size. In this study, based on the signal detection theory, the actual POD was estimated by the signal amplitude (defect size) and observed reflection position of field experience data. It was confirmed that the POD is decreased with a less than 3.2 mm depth. The estimated POD for each crack depth well matches the result of laboratory experience data. The probability of failure for piping system was calculated based on this estimated POD, it was lower than 10-7 in case of stress corrosion cracking (SCC) on low carbon stainless steel piping SCC, and it was lower than 10-3 in case of SCC on sensitized stainless steel 304. In order to keep the probability of failure is 10-3 or less, it is only necessary that the POD is 0.95 or greater for large crack as 3.2 mm depth or more. Based on these result, this paper proposed the acceptance criteria for qualification test as training graduation.

著者

古巣 克也 尼子 龍幸 中川 稔章 浜辺 勉 青木 典久

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.84, no.858, pp.17-00326-17-00326, 2018 (Released:2018-02-25)

参考文献数

24

被引用文献数

1

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In this study, a formula describing on the flattening phenomenon when a bending moment acts on a box beam was derived considering the cross-sectional deformation. Calculation results obtained using the derived formula were then compared with results acquired using the finite element method (FEM). The case of a bending moment acting on a box beam composed of four thin plates that permits cross-sectional deformation along the longitudinal direction was investigated with the following assumptions: the boundaries of these plates is are simply supported, an equally distributed load acts on these plates, and the width along the neutral line of the plates is retained after deformation. Furthermore, on the basis of the coupling of the deflections of adjacent plates and the thin plate theory, the moment of inertia of cross section was obtained as a function of the curvature of the box beam. A formula relating the bending moment to the curvature is was then derived. Calculation results from this derived formula were compared with FEM results modeling only the cross section using generalized plane strain elements. For box beams with a square cross section, the maximum moments and curvatures calculated from the derived formula were within 5% of the FEM results. This indicates that it is important to consider the reduction in the cross section that accompanies the bending of the plates. Regarding general box beams with a rectangular cross section, the influence of the aspect ratio of the cross section was found to be considerably larger in the FEM results than in the derived formula. The reason for this difference may be that plates do not satisfy the abovementioned assumptions regarding the boundary and load conditions of the plates; however, confirming this remains a task for future work.

著者

山川 雄司 遠山 渉 黄 守仁 村上 健一 石川 正俊

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.84, no.858, pp.17-00364-17-00364, 2018 (Released:2018-02-25)

参考文献数

19

被引用文献数

2

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Human motion is very flexible for performing various tasks but has low speed and low precision; therefore, support and assistance of human motion by robots is desirable in some situations. In this study, in order to achieve such functions, we developed a new portable module for accurately controlling the position of a human hand and constructed a high-speed, high-accuracy positioning control system using image tracking via a high-speed vision system. In order to evaluate its performance, we executed tracing tests of constant position, circular or linear trajectory. Finally, we performed the task of catching a falling small ball, as a significantly difficult positioning task. Although this task was nearly impossible to perform with the human hand alone, the success rate was dramatically improved by using the proposed method.

著者

日野 遥 田村 卓也 杉本 大己 高橋 優輔 橋本 成広

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.84, no.858, pp.17-00368-17-00368, 2018 (Released:2018-02-25)

参考文献数

9

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It is already known that micro gravity affects astronaut’s body. In contrary, hyper-gravity might affect myoblasts. In the present study, mouse muscle cells (C2C12) were cultured four five hours in hyper-gravitational environment (50 G, 100 G) using the centrifugal machine placed in the incubator. Cells were observed at the incubator microscope for 24 hours after stopping centrifugation. The contour of each cell at the time-lapse images was approximated to the ellipsoid and several parameters were calculated: the angle, the area, and the aspect ratio. Each cell tends to shrink from the extended shape under hyper-gravitational environment. The directions of the major axis at 50% of cells tilt to the parallel direction to the hypergravity. After 24 hours, 51% of cells tilt to the perpendicular direction of the hypergravity in the 50 G group. The result shows that the history of hyper-gravitational environment affects the shape of cells.

著者

日野 遥 杉本 大己 篠崎 祐輔 高橋 優輔 橋本 成広

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.84, no.858, pp.17-00166-17-00166, 2018 (Released:2018-02-25)

参考文献数

18

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A parallel-piped flow channel with micro-striped patterns has been designed to study the effect of the shear field on the myoblast in vitro. The micro-pattern was manufactured with the photolithography technique and used for the scaffold of the cell culture in the flow chamber placed in the incubator on the microscope. Variation was made on the angle between the stripe of the pattern and the flow direction: 0, 45, and 90 degrees. After cultivation for 4 hours, C2C12 (mouse myoblast cell line) adhered on the micro-pattern was exposed to the shear flow for 4 hours. The wall shear stress is estimated from the parabolic velocity profile in the medium between the parallel walls. With the experimental system, the following tendencies of responses (deformation, orientation, and migration) of each cell was observed. Under the wall shear stress of < 3 Pa, each cell deforms to the round shape at first, and extends again along the stripe-pattern. Orientation of each cell is collapsed during exposure to the wall shear stress of 3 Pa, and is recovered after stopping exposure to the shear field. The results show that the experimental system is available to investigate quantitatively the effect of mechanical stress field on the oriented cell.

著者

水谷 建 榎本 俊之 小園 典也 佐竹 うらら 杉原 達哉

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.84, no.858, pp.17-00356-17-00356, 2018 (Released:2018-02-25)

参考文献数

22

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Bone grinding with miniature ball-end diamond wheels, called diamond burs by surgeons, is widely used for surgical resection of bones, especially in orthopedic surgery and neurosurgery. During bone resection, a considerable amount of grinding heat is generated, which can cause thermal injury to adjacent tissues, including nerves. To address this problem, several types of countermeasures such as irrigation, namely coolant supplying methods, have been developed; however, the existing measures cannot suppress the excessive heat generation. To solve this problem, our previous studies proposed surgical diamond grinding wheels with titanium dioxide (TiO2) particles deposited surfaces for preventing strong loading of bone swarf on the wheel surfaces due to hydrophilicity of TiO2 and found that such wheels reduced the grinding-induced temperature elevation. However, in the experiments, pure water was used as coolant instead of saline, which is typically used in surgery. Then the grinding performances of the wheels under a saline supply were investigated. The experimental results revealed that sodium ion in saline promoted the strong loading on the wheel surface through Maillard reaction and, as a result, the grinding-induced temperature increased rapidly and finally exceeded the threshold for thermal injury. Based on our findings, new grinding wheels with fluorine-treated surfaces were developed in the hopes of promptly shedding of the adhesion of bone swarf on the wheel surface. These wheels significantly and stably suppressed bone temperature elevation compared with commercial and previously developed wheels.

著者

中 尚義 橋本 巨

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.82, no.833, pp.15-00209-15-00209, 2016 (Released:2016-01-25)

参考文献数

11

被引用文献数

1 1

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Dragonflies can perform both of gliding and flapping flight and have high maneuverability in spite of small-size. The aim of this study is to develop Micro Air Vehicle (MAV) based on the flight of dragonfly. The characteristics of wings are very important for development of MAV. Dragonfly wing is easy to be passively deformed in the tip side from the nodus in flapping flight, and thereby, aerodynamic force is generated effectively. In this study, the effect of passive deformation of wing on aerodynamic force was investigated using fluid-structure interaction analysis to develop the artificial wing suitable for dragonfly-like MAV. In this study, aerodynamic characteristics of wings in the gliding flight and aerodynamic force generated in flapping flight are numerically analyzed. In this analysis, nodus wing models, which can deform passively, and rigid wing model, which cannot deform, are used. Nodus wing model imitates the nodus structure; the tip side of this model is free to rotate around leading edge. As a result of gliding flight, the lift coefficient of the nodus wing was lower in low-angle of attack and was higher in high-angle of attack, compared to rigid wing. Moreover, the more flexible wings are, the more change. The gliding flight is low-angle of attack usually. Therefore, flexible wing is less suitable for the gliding flight than inflexible wing. As a result of flapping flight, the nodus wing made drag force generated during down stroke lower compared with the rigid wing. However, thrust forces generated during up stroke in both wings were the same. Therefore, flexible wing is more suitable for the flapping flight than inflexible wing. The wings of dragonfly-like MAV need to appropriate level of flexibility to upgrade the performance in both case of gliding and flapping flight.

著者

野中 朋美 清水 香那 水山 元

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.82, no.842, pp.16-00166-16-00166, 2016 (Released:2016-10-25)

参考文献数

12

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This paper proposes a dynamic table assignment method for a restaurant to reduce customer waiting time and inequality of lengths of waiting among customers. It develops a simulation model to estimate the remaining time until departure of each customer and evaluates effective sequences of table assignment in terms of waiting times and availability of tables using the model virtually. Gini coefficient value is used as an evaluation index for measuring inequality. In this paper, two conventional table assignment rules and the proposed method are described. Computer experiments demonstrate that the proposed method is superior to the conventional rules which assign in First In First Out (FIFO) way or assign smaller customer groups before larger ones.

著者

植木 洋輔

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.81, no.821, pp.14-00225, 2015 (Released:2015-01-25)

参考文献数

7

被引用文献数

1

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The objective of this study is to establish a methodology for high-speed fatigue testing, especially for resin materials, which includes fiber reinforced composites. To exert periodic stress on a material at a frequency of more than 200 Hz, a specimen was fixed as a cantilever to an electromagnetic vibrator and vibrated in its resonant frequency of the 1st bending mode by using a resonance tracking control. The shape of a specimen made of glass fiber-epoxy laminate was designed with finite element vibration analysis to obtain a resonant frequency of more than 200 Hz and a desired strain distribution for inducing fatigue damage under a certain stress level. A rise of temperature during the fatigue testing due to damping loss was estimated with a heat transfer theory and suppressed by external cooling to keep the specimen at a normal temperature. To confirm the validity of the high-speed testing, a completely reversed bending test at 1 Hz with identical specimens was also performed. Results both from testing at 230 Hz and 1 Hz were plotted on a single power-law curve in an S-N plot, which is a well-known fitting for fiber reinforced composites. This result suggests that we can evaluate fatigue strength in the high- or giga-cycle region for resin and composites in a very short time if temperature is controlled appropriately.

著者

佐藤 俊之 阿部 梨恵 齋藤 直樹 永瀬 純也 嵯峨 宣彦

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.81, no.827, pp.15-00084-15-00084, 2015 (Released:2015-07-25)

参考文献数

13

被引用文献数

2 3

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This paper addresses position and path-tracking problems of robot manipulators subject to constraints on both the magnitude and difference of the control input. Along with the model predictive control (MPC), the disturbance observer (DOB) is used to compensate for disturbances and nominalize the plant dynamics. To constrain the total control input, which is the sum of the MPC output and DOB output, we adopt time-varying input constraints and construct a useful structure of the combined DOB-MPC system. The effectiveness of the proposed control scheme is validated through a few experiments using a real two-link manipulator.

著者

中山 万希志 奥井 博己 木村 尚人 栗屋 効典

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.84, no.857, pp.17-00362-17-00362, 2018 (Released:2018-01-25)

参考文献数

12

被引用文献数

1

---

In this paper, we discuss a modeling method and an altitude control system for a drone type UAV using the image information from the forward camera of the UAV. The model for the UAV dynamics is constructed based on the motion equation and the unknown velocity control logic which was made the internal organs in the drone system, and the parameters of the model are obtained by some experiments of the velocity constant control. The transfer function are expressed the 2 dimensional state space equation, and the optimal control method applied to the system include some limitation of the velocity control logic. This optimal control logic is realized as a PID control system. The P gain range of the PID controller is determined by the parameter of performance index of optimal control logic and the system keep optimal control feature in the range. By the experimental results, we confirmed that this system is stable and efficient.

著者

武田 真和 渡辺 昌宏

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.84, no.858, pp.17-00415-17-00415, 2018 (Released:2018-02-25)

参考文献数

16

被引用文献数

3

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This paper presents experiments and an analysis of the self-excited vibration of a plate supported by air pressure. In the analysis, the unsteady fluid force acting on the plate is calculated based on the basic equation of a two-dimensional gap flow between the plate and a chamber surface. The basic equation considers the effect of air compressibility in the chamber. The characteristic equation of the system is derived from the plate motion coupled with the unsteady fluid force acting on the plate. The instability condition and vibration frequency are predicted through the root locus of the system with changing air flow rate supplied to the chamber. The experiment consists of a plate supported by the air pressure supplied from a slit on the upper surface of the chamber, where the vibration characteristics are examined. The influence of the slit width and chamber volume on the instability condition of the self-excited vibration is clarified comparing the analytical result with experiments. Moreover, the local work done by the unsteady fluid force acting on the plate (bottom surface) is shown in this paper, and the instability mechanism is discussed. Lastly, the influence of slit width on the unsteady fluid force is addressed by the block diagram showing the phase relationship of pressure fluctuation and plate displacement.

著者

小原 伸哉 伊藤 優児 岡田 昌樹

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.856, pp.17-00266-17-00266, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

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To level the fluctuations in electric power sourced from renewable energy, the transmission network can be spread over a wide area, but this is expected to dramatically increase the renewable energy rate. Therefore, this paper proposes an algorithm that analyzes the maximum amount of renewable energy in the network, and hence optimizes the type of electric power source connected to the transmission network, and the arrangement and capacity of each power source. The proposed algorithm is based on a genetic algorithm, which effectively processes many nonlinear variables concurrently. Accounting for the power interchange in the transmission network and the energy storage in electric heat pumps and heat storage tanks, the objective function plans the arrangement of the electric power sources that maximizes the economic efficiency of the system. The developed algorithm is applied to a renewable-energy network in Hokkaido, Japan. In this area, the introductory rate of renewable energy was 39.5% of the total electricity production. Moreover, the cost of a distributed power-supply network was 9.99 × 1010 USD. The proposed system is equivalent to 1.88 years of Hokkaido's energy consumption.

著者

岡田 和也 佐藤 明 二村 宗男

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.856, pp.17-00378-17-00378, 2017 (Released:2017-12-25)

参考文献数

16

被引用文献数

1

---

We have investigated a regime change in the aggregate structures of a suspension composed of magnetic cubic particles in thermodynamic equilibrium, by means of Monte Carlo simulations. In concrete, we have addressed the dependence of the regime change on a variety of factors such as the magnetic field strength and the magnetic particle-particle interaction strength. The orientational distribution function and order parameters have been focused on for quantitatively discussing these characteristics. The main results obtained here are summarized as follows. If the magnetic interaction strength is sufficiently large for cluster formation, closely-packed clusters are formed under the combination and expansion of a cluster unit composed of 8 particles. A regime change in the internal structure of aggregates appears in a narrow range of the magnetic interaction strength, which is clearly exhibited by the order parameter employed here. A closely-packed configuration can be clearly characterized by the orientational distribution function; 8 high peaks appear in the orientational space in the case of the closely-packed structure. As the magnetic field is increased, the closely-packed clusters are collapsed and transformed into wall-like clusters along the magnetic field direction. This is because the magnetic moment of each particle has a strong tendency to incline in the magnetic field direction in the situation of a strong magnetic field.

著者

横山 真男 瀬田 陽平 矢川 元基

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.856, pp.17-00287-17-00287, 2017 (Released:2017-12-25)

参考文献数

15

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Based on experimental observation of liquid dripping, a method to prevent liquid adhesion at the wall of cup was proposed in this paper. When water or sauce etc. is poured from edge of a cup or a pot, the liquid adheres to the wall of cup, which often makes a table or clothes dirty. To clarify the above annoying problem, the flow dripping from the cup, whose edge was shaped to have various thin channels, was observed by using high speed camera. We found the water adhesion on cup's wall reduced when the channels were located at the outside of edge of the cup.

著者

天野 歩 阪口 基己 黒川 悠 岡嶋 芳史 井上 裕嗣

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.856, pp.17-00377-17-00377, 2017 (Released:2017-12-25)

参考文献数

28

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In order to investigate the fundamental process of residual stress development in thermal barrier coating during thermal spray, a model experiment was conducted using a paraffin wax. Melted paraffin wax was dropped onto a circular substrate of type 430 stainless steel, and strain and temperature were measured on the back surface of substrate. The model experiment revealed that tensile quenching strain was developed during solidification and adhesion process and it was increased with the number of droplets. Development of the quenching strain and failure of paraffin coating were significantly influenced by substrate temperature. The lower substrate temperature caused the larger quenching strain, and facilitated cracking, delamination and debonding of the coating. Findings in a series of the model experiments showed some similarities to actual phenomena during thermal spray, and will provide a helpful suggestion to optimize various process parameters in thermal spray.

著者

上 剛司 山田 浩之 小笠原 永久

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.856, pp.17-00261-17-00261, 2017 (Released:2017-12-25)

参考文献数

37

被引用文献数

1

---

Indentation tests are used to determine the local mechanical properties of materials. Previously, the indentation strain rate was correlated with the strain rate in uniaxial tests based on the hardness, which was the obtained load divided by the cross-sectional area. However, the hardness can be influenced by pile-up of material after indentation. The purpose of this study was to relate the indentation strain rate with the uniaxial strain rate through serration behavior. The material used in this study was 5082 aluminum alloy, whose main alloying elements are aluminum and magnesium, and which is known to exhibit serration at certain temperatures and strain rates. Quasi-static uniaxial tensile tests were performed at strain rates from 10-4 to 10-1 s-1 at room temperature. Micro-indentation using a Berkovich indenter was performed at constant loading rates from 0.7 to 350 mN/s. The loading curvature, which was defined as the load divided by the square of the displacement, was used instead of the hardness to avoid the pile-up effect. As a result, the serrated loading curvature in the indentation tests was obtained as the decreasing loading rate. The effective strain rate, which was defined as the derivative of the load with respect to time divided by two times the applied load, decreased with increasing displacement. The serrated loading curvature changed its behavior as the effective strain rate decreased. It behaved similarly to the serration observed in uniaxial tensile tests. It was found that the indentation strain rate is correlated with the strain rate in uniaxial tensile tests through the serration behavior.

著者

吉中 奎貴 中村 孝 髙久 和明 塩澤 大輝 中井 善一 上杉 健太朗

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.856, pp.17-00104-17-00104, 2017 (Released:2017-12-25)

参考文献数

23

被引用文献数

2

---

The initiation and growth of internal small fatigue cracks with around ten or several dozen μm in Ti-6Al-4V were nondestructively examined by using synchrotron radiation μCT at the large synchrotron radiation facility SPring-8. Lots of grain-sized internal cracks were observed roughly evenly in the observation volume in the specimen; in contrast, only one surface crack was detected. The initiation lives of the internal cracks were widely different for each crack and had no significant correlation with the crack initiation site nor the initial crack size. The internal cracks propagated microstructure-sensitively with several crack deflections, and the growth rates were very small, less than 10-10 m/cycle. The crack growth rates just after facet formations showed large variability and had no apparent relationship with the crack initiation life nor the initial crack size. This variability can likely be attributed to microstructural inhomogeneities around the crack initiation facets. The estimated facet formation rate indicated that most facets formed rapidly compared with the following internal crack growth rate.

著者

林 晃生 中尾 陽一

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.856, pp.17-00268-17-00268, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

---

Recently, the ultra-precision parts have become essential in many areas of advanced technology, including medical equipment, aircraft equipment, optical equipment and so on. These ultra-precision parts are required to have a high surface quality. Therefore, further precise machining and motion accuracy are required for the ultra-precision machine tools that machine these parts. Thus, the water-driven spindle, which is equipped with water hydrostatic bearings and a water-driven mechanism, was developed for ultra-precision machine tools. This spindle has higher stiffness than a spindle supported by aerostatic bearings. However, the heat generation due to fluid viscosity occurs at the bearings. If the temperature of each part in the spindle changes, undesirable deformation of the parts will occur. Deformation of the spindle during the machining process will then degrade the machining accuracy. In contrast, the water-driven spindle uses water as a lubricating fluid. Furthermore, water flow is supplied into the spindle in order to generate the driving power. Therefore, the water flow is an effective cooling medium for the water-driven spindle. Water cooling can be used to improve the thermal stability of the spindle because water has higher thermal conductivity and higher specific heat. In the present paper, the thermal stability of the water driven spindle is investigated experimentally. As a preliminary step, the changes in temperature of the water flow and the outer surface of the spindle are measured experimentally during spindle rotation at various rotational speeds. Furthermore, the influence of the power loss during spindle rotation on the temperature change of the water flow is investigated through calculations and experiments.

著者

寺井 久宣 浅尾 晃通 吉川 浩一 水垣 善夫

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.856, pp.17-00265-17-00265, 2017 (Released:2017-12-25)

参考文献数

11

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The ball end mill is used as a tool for cutting the metal mold and some complicated shape lake a screw. The demand for the precise machining of the ball end milling is increasing. The ball end milling has the unavoidable problem of machining error by the elastic deformation of tool because of its low rigidity. So this report is set up the new method of the high precision machining used by the tool orientation control. The machining area at the point of the surface generation is changed depend on the tool orientation of the ball end mill. The geometric mechanism is analyzed and the relationship between the machining area and the tool orientation is clarified. And the cutting force and the machining error are measured by the machining test that the tool orientation has been varied. As the result, it is verified that the machining error becomes large at the point, which the machining area is large. And the machining error estimation index has been proposed and calculated about three dimensional surface.