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

---

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

片桐 拓也 佐々木 幸太 遊佐 訓孝 橋爪 秀利

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

巻号頁・発行日

vol.84, no.859, pp.17-00375-17-00375, 2018

被引用文献数

5

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<p>This study proposes nondestructive long-range inspection for axial cracks appearing at the inner surface of a metal pipe using microwave. Numerical simulations were conducted to design a mode converter that converts TEM into TE mode that is necessary to detect axial cracks. The simulations confirmed that situating coaxial cables circumferentially enables to propagate microwaves in TE mode inside a pipe. The results also revealed that the number and positions of coaxial cables affect the frequency range where microwaves propagate as TE₀₁ mode dominantly. A mode converter with four coaxial cables was fabricated according to the results of the simulations aiming at the propagation of microwaves as TE₀₁ mode. Experimental verification was conducted using a brass pipe with a total length of 11.6 m and an inner diameter of 19.0 mm, and having the mode converter at the center. The results showed significant difference between the signals with and without an artificial slit simulating a crack. This study also proposed a signal processing method to compensate for the dispersion of microwaves with an aid of a window function. The signal processing method gave the clearer signals corresponding to the slits to determine the predict position of the slit quantitatively using the time-of-flight of the signals.</p>

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

---

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

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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

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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.

著者

野口 晋 西田 勇 佐藤 隆太 白瀬 敬一

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.17-00254-17-00254, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

---

It is known that the cutting force excites the structural vibration of machine tool. In addition, cutting force acts on feed and spindle drive system as a force disturbance, and feed speed and spindle speed are changed. As the results, cutting force is also changed because the depth of cut and cutting speed are changed due to the machine vibration, feed and spindle speed changes. The purpose of this study is to analyze the coupled vibration between the machine tool behavior and the cutting force. In order to achieve the purpose, in this study, a coupled simulation method of the vibration of machine tool, the dynamic behaviors of feed and spindle drive systems and the cutting force is developed. Cutting force and machined surface geometry is simulated using the voxel simulator in which the workpieces is represented by voxels. Undeformed chip thickness can be calculated based on the relative position between the tool and workpieces, and the tool rotational angle at the each time step based on the voxel model. The cutting force is estimated based on the calculated undeformed chip thickness. The relative position between tool and workpiece at each time step is simulated by the feed drive system and machine tool structural models. The tool rotational angle is simulated by the spindle drive system model. The coupled simulation between the cutting force, structural vibration of machine tool and feed and spindle drive systems is carried out by applying the simulated cutting force and cutting torque as a disturbance to the feed and spindle drive systems and machine tool structure. Cutting tests and simulations are carried out with two kinds of radial depth of cut, 5 mm and 20 mm. It is confirmed that the machine tool dynamic behaviors due to the cutting force and torque which is also influenced by the machine tool behaviors can be simulated by the proposed method. It is also confirmed that the chatter vibration which is observed in case of the 20 mm depth of cut can be simulated by the proposed method.

著者

高橋 辰伍 板野 健太郎 中本 圭一

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.17-00249-17-00249, 2017 (Released:2017-12-25)

参考文献数

13

被引用文献数

1

---

Agile manufacturing that can rapidly machine advanced materials or creative shapes is expected as an important key to realize mass customization of industrial products. Most of high-value-added workpieces have three dimensional and complex shapes. Thus, the workpiece shape and stiffness vary greatly according to cutting procedure during a rough machining operation. The induced displacement of workpiece strongly affects machining accuracy and tool life. However, it is difficult to automatically determine the process planning in commercial CAM system because of a large number of combinations. Therefore, the process planning has been designed by skillful experts to achieve complex parts machining. In order to realize future high efficient machining, it is necessary to obtain these tacit knowledges and to formulate the implicit machining know-how owned by skillful experts. As the first step, a method is proposed to decide workpiece shapes during a rough machining operation to ensure the workpiece stiffness based on topology optimization in this study. Topology optimization that is known as one of the highly flexible structure optimization methods enables to deal with the target configuration and shape. By introducing changeable fixed design domain and discretized characteristic function, an optimization problem can be converted to a problem of material distribution. In this study, the topology optimization is applied to decide workpiece shapes during a rough machining operation. As a purpose of minimizing their mean compliance, the optimized workpiece shape is calculated depending on applied loads at each machining step. By using the calculated workpiece shapes, a case study of complex parts machining is conducted. From the result, it is confirmed that a rough machining operation of complex parts can be achieved according to the decided workpiece shapes.

著者

金子 和暉 西田 勇 佐藤 隆太 白瀬 敬一

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.17-00247-17-00247, 2017 (Released:2017-12-25)

参考文献数

9

被引用文献数

3

---

In end milling, in order to improve machining efficiency and accuracy, instantaneous rigid force model is widely used to predict cutting force and improve cutting conditions. The instantaneous rigid force model is well known as the practically simple model to predict cutting force. However this model requires the six parameters called cutting coefficients which have to be determined by the experimental milling operation. So several experimental milling operations are needed before cutting force prediction. In this study, a new instantaneous rigid force model based on oblique cutting is proposed. In this force model, the end milling process is modeled using the oblique cutting model. Therefore, cutting force prediction can be realized using only the one parameter such as shear angle instead of the six parameters such as cutting coefficients required for a conventional instantaneous rigid force model. The shear angle can be determined from tangential milling force or milling torque. And this force model is easier to apply for practical cutting force prediction, because time and effort to determine the parameter(s) before cutting force prediction. The validation of this force model compared with the conventional force model is performed. As the result, cutting forces predicted by the proposed force model has good agreement with the measured cutting forces. Also, the proposed force model has good performance in a wide range of cutting conditions compared with the conventional force model.

著者

冨江 瑛彦 久慈 千栄子 赤塚 亮 佐々木 啓一 嶋田 慶太 水谷 正義 厨川 常元

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.83, no.856, pp.17-00169-17-00169, 2017 (Released:2017-12-25)

参考文献数

3

被引用文献数

1

---

Powder jet machining is one of blasting processes conducted under room temperature and atmospheric pressure. This process brings both deposition and removal process, and in this study, it refers to powder jet deposition (PJD) and abrasive jet machining (AJM). As an application of PJD, the authors have proposed an innovative dental treatment method with the hydroxyapatite (HA) fine particle. By this method, thick HA coating can be fabricated directly in the human oral cavity. In this study, the effect of the particle impact angle was investigated as a parameter that affects the machining phenomenon. The experiments showed that the machining phenomenon transited depending on the blasting angle. In the vertical blasting condition, PJD process was just observed. On the other hand, in the more acute blasting angle such as 45 deg. or 60 deg. both coating and removal process appeared at the same time and in the most acute angle of 30 deg. only removal process was detected. The TEM observations showed that the impact surface of the HA substrate deformed and the deformation depth increased as the blasting angle get more acute. The smoothed particle hydrodynamics (SPH) method was utilized for the analysis for the fracture behavior of the HA substrate. The result indicated that the decrease of the impact angle induced the increase of the strain and the temperature of the interface between the particle and the substrate. Thus it is concluded that the shear stress, which refers to the impact angle, induces the destruction of the substrate by the deformation and the brittle fracture due to the thermal stress.

著者

辻野 元大 古城 直道 山口 智実 廣岡 大祐 松田 茂敬 岩佐 康弘 寺内 俊太郎

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.17-00161-17-00161, 2017 (Released:2017-12-25)

参考文献数

18

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Diamond cutting tools show severe wear in turning of steels. In previous paper, it was shown that carbides on ferrite phase, which were precipitated by carburization, suppressed the diamond tool wear. In this paper, detailed distribution of constituents of the carbides was analyzed by EDS (energy-dispersive X-ray spectroscopy). In addition, characteristics of each carbide such as occupancy, diameter, and degree of circularity were measured. Results indicate that those characteristics of the carbides influence suppression of the tool wear.

著者

道辻 洋平 石井 翔 長澤 研介 松本 陽 大野 寛之 佐藤 安弘 緒方 正剛 谷本 益久 岩本 厚 福島 知樹 品川 大輔

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.83, no.856, pp.17-00283-17-00283, 2017 (Released:2017-12-25)

参考文献数

15

被引用文献数

5

---

It is important to secure running safety of railway vehicles against wheel-climb derailment accidents. The safety is often discussed according to the value of derailment coefficients for the leading outside wheel of a railway bogie running on sharp curves. Therefore, the detailed force induced mechanism which influences the value of derailment coefficients should be clarified. One of the most dominant factors affecting the value of derailment coefficients is magnitudes of the coefficient of friction (COF) between wheel and rail. Since the gauge corner of the outer rail and the top of the inner rail are lubricated at some sharp curves, COF of wheels of a bogie are different from each other and show complicated variation. In this study, the effect of lubrication for the running safety of the railway bogie is investigated while considering the detailed force induced mechanism of the derailment coefficient increase utilizing both multibody dynamics simulations and experiments. Experiments and simulations are conducted with a roller-rig test equipment under various conditions of wheel/rail lubrication. In this research, a method to identify whether the bogie is in suitably lubricated condition in terms of running safety is discussed. The proposed method making use of the longitudinal force measurement with mono-link type axle supporting device is mentioned.