著者

萩野 直人 吉田 博夫 今田 晴彦

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

pp.15-00596, (Released:2016-04-25)

参考文献数

16

被引用文献数

1

---

The self-circulating thermosyphon (SCTS) operates without external pumping power. It is a closed loop of pipe and consists of heater, condenser, heat exchanger and recuperator. In this paper the basic performance of SCTS was examined experimentally under various back ground pressures and power inputs to the heater. Experimental results showed that the stable operation of SCTS was limited by the minimum input power overcoming the total losses of the system and the maximum power within the ability of the condenser. At fixed back ground pressure, mass flow rate and quality of water vapor in heater were confirmed to increase with the power input. As back ground pressure increased, mass flow rate was prone to decline. Those suggest that the main driving force of SCTS is buoyancy force of the vapor. Thermal transport efficiency ranged from 0.4 to 0.9 as far as the present conditions are concerned.

著者

村岡 祥雄 関 研一 西村 秀和

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.835, pp.15-00480-15-00480, 2016 (Released:2016-03-25)

参考文献数

15

---

Thermal design of electronic products has become increasingly complicated with leakage current characteristics and their variation of semiconductors. This paper proposes an application of a thermal system model to a production system of electronic products. The thermal system model is developed for architecture design to determine design parameters of modules. The model is described with Systems Modeling Language (SysML) considering interactions among parameters of mechanical structure and electrical components that include semiconductors with temperature-dependent leakage current characteristics. In the system model, constraints of heat generation and heat transfer are described using equations and relation between equations and parameters are clarified in parametric diagram. The system model that is developed at the early stage of product design is used at the beginning of integration, such as receiving inspection. To prevent quality degradation by variation in component characteristics, semiconductor components such as processing units are screened with thermal simulation result before their implementation on Printed Wiring Board (PWB). The simulation result is being referred to temperatures that cause low-temperature burn injury. As a case study, a system model of portable product is developed and demonstrates thermal simulation to determine limitation in large variation in leakage current characteristics to satisfy product thermal quality. To improve yield ratio of the semiconductor components after screening, system models are developed for various products in which same processing units are installed. The system model can be applied for each product changing the design parameters and simulate to determine allowable range of component characteristics keeping the product quality. Implementing a component that causes more leakage effect into a product that has more allowable range, degradation of product quality can be avoid without losing the component yield ratio.

著者

藤川 正毅 石川 清貴 真壁 朝敏 田中 真人 笹川 崇 表 竜二

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.834, pp.15-00454-15-00454, 2016

被引用文献数

5

---

This paper proposes a novel implementation scheme of geometrically nonlinear finite element programs, which automatically compute exact internal force vectors and element stiffness matrices by numerically differentiating a strain energy function at each element. This method can significantly simplify the complex implementation procedure which is often observed in conventional finite element implementations, since it never requires B matrices, stress tensors, and elastic tensors by hand. The proposed method is based on a highly accurate numerical derivatives which use hyper-dual numbers and never suffer from any round-off and truncation errors. Several numerical examples are performed to demonstrate the effectiveness and robustness of the proposed method.

著者

藤川 正毅 石川 清貴 真壁 朝敏 田中 真人 笹川 崇 表 竜二

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

2016

被引用文献数

5

---

This paper proposes a novel implementation scheme of geometrically nonlinear finite element programs, which automatically compute exact internal force vectors and element stiffness matrices by numerically differentiating a strain energy function at each element. This method can significantly simplify the complex implementation procedure which is often observed in conventional finite element implementations, since it never requires B matrices, stress tensors, and elastic tensors by hand. The proposed method is based on a highly accurate numerical derivatives which use hyper-dual numbers and never suffer from any round-off and truncation errors. Several numerical examples are performed to demonstrate the effectiveness and robustness of the proposed method.

著者

片峯 英次 今井 伸哉

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

pp.15-00578, (Released:2015-12-24)

参考文献数

21

被引用文献数

1

---

This paper presents a numerical solution to shape identification of unsteady natural convection fields to control temperature to a prescribed distribution. The square error integral between the actual temperature distributions and the prescribed temperature distributions on the prescribed sub-boundaries during the specified period of time is used as the objective functional. Shape gradient of the shape identification problem is derived theoretically using the Lagrange multiplier method, adjoint variable method, and the formulae of the material derivative. Reshaping is carried out by the traction method proposed as an approach to solving shape optimization problems. Numerical analyses program for the shape identification is developed based on FreeFem++, and the validity of proposed method is confirmed by results of 2D numerical analyses.

著者

米倉 一男 寒野 善博

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

pp.15-00337, (Released:2015-12-04)

参考文献数

24

---

We propose a Newton-gradient-hybrid optimization method for fluid topology optimization. The method accelerates convergence and reduces computation time. In addition, the fluid-solid boundaries are clearly distinguished. In the method, the optimization process and flow computation are executed concurrently. The flow computation utilizes the lattice Boltzmann method (LBM), and the optimization algorithm partly utilizes a Hessian matrix. Due to the formulation of LBM and the optimization algorithm, the Hessian matrix is a diagonal matrix. Since the optimization problem is nonconvex problem, the Hessian matrix is not generally positive semidefinite. Hence, we employ a gradient method for a component whose corresponding Hessian matrix elements are negative. We compare the optimization results with those of conventional gradient method and show that the convergence is accelerated and the fluid-solid boundaries are clearly distinguished.

著者

釜谷 昌幸 北條 智博 望月 正人

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.80, no.817, pp.SMM0252-SMM0252, 2014 (Released:2014-09-25)

参考文献数

44

被引用文献数

2 2

---

Load carrying capacity of austenitic stainless steel component is increased due to hardening caused by neutron irradiation if no crack is included in the component. On the other hand, if a crack is initiated in the reactor components, the hardening may decrease the load carrying capacity due to reduction in fracture toughness. In this paper, in order to develop a failure assessment procedure of irradiated cracked components, characteristics of change in failure strength of stainless steels due to cold working were investigated. It was experimentally shown that the proof and tensile strengths were increased by the cold working, whereas the fracture toughness was decreased. The fracture strengths of a cylinder with a circumferential surface crack were analyzed using the obtained material properties. Although the cold working altered the failure mode from plastic collapse to the unsteady ductile crack growth, it did not reduce failure strengths even if 50% cold working was applied. The increase in failure strength was caused not only by increase in flow stress but also by reduction in J-integral value, which was brought by the change in stress-strain curve. It was shown that the failure strength of the hardened stainless steel components could be derived by the two-parameter method, in which the change in material properties could be reasonably considered.

著者

岩田 郷志 宅間 正則 齋藤 賢一 松井 淳基 高橋 可昌 都築 勇人

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.80, no.818, pp.SMM0292-SMM0292, 2014 (Released:2014-10-25)

参考文献数

18

---

A6061-T6 alloy has been used in the liner material of high-pressure hydrogen gas storage container that is mounted on a fuel cell vehicle. The degradation of the properties such as strength, toughness and hydrogen embrittlement resistance, etc., has been pointed out, because the grain structure of the mouthpiece part of the liner becomes coarse in the manufacturing process. The tensile and fatigue test for the specimens with different grain size were done, and the detected AE signals during the testing were analyzed. In the tensile test, the characteristics of the signals on dislocation motion, transgranular and intergranular fracture were extracted. In the fatigue test, it was shown that the possibility of which the damage is evaluated by the spectral analysis that utilizes the slope of an approximation straight line in the both logarithmic scale display of FFT analysis result. Then we proposed the amplitude ratio Rv that is the parameter which divided the maximum amplitude of signal for intergranular fracture by that of detected signal, and the correlation between the grain size and the Rv was recognized. These proposed information are able to be utilized in order to evaluate the damage of the container.

著者

滝田 好宏 伊達 央 大川 真弥

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.80, no.812, pp.TRANS0069-TRANS0069, 2014 (Released:2014-04-25)

参考文献数

19

---

This paper proposes SSM (Sensor Steering Mechanism) for a lateral guided vehicle with an articulated body. Authors demonstrated the simple lateral guiding method SSM for the front wheel steer type, the reverse phase four-wheel steer type and the rear wheel steer type vehicle. SSM presents the stable lateral guiding performance for automated vehicle which follows a straight and curved path created by guideway. This paper proposes a simplified SSM to remove the following servo system for the camera rotation. The simplified SSM is applied to 1/25 scaled articulated dump truck which is developed by the previous paper. The stability of the simplified SSM is discussed. Experimental and simulation results show the stable moving and the performance of proposed method.

著者

前田 慎市 菅野 祥一郎 古藤 亮平 小原 哲郎

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

pp.14-00332, (Released:2015-01-16)

参考文献数

26

被引用文献数

1

---

The gaseous detonation driven gas gun was developed for accelerating the projectile to a supersonic speed. The gas gun was simply consisted of two straight stainless-steel tubes. The one was the detonation tube and the other was the launch tube. The detonation tube was 50 mm inside diameter with 2180 or 4280 mm long, and the launch tube was 5 mm inside diameter with 1040 mm long. Chapman-Jouguet detonation wave was initiated in the detonation tube, and the projectile was accelerated in the launch tube via combustion products behind the detonation wave. The spherical projectile of 4.76 mm diameter was made of high-density polyethylene with 52 mg mass. The driver mixture was stoichiometric hydrogen-oxygen premixed gas with initial pressure ranging from 120 to 450 kPa. The gas gun was successfully operated, and the maximum projectile velocity of 1400 m/s was obtained for the conditions that the detonation tube was 4280 mm long and the initial pressure of the driver gas was 450 kPa. The results of the longer detonation tube demonstrated that the projectile velocity was 1.15 - 1.25 times higher than the case of shorter detonation tube. This velocity change of the projectile could be explained by the pressure increase at the inlet of the launch tube by using longer detonation tube. The reason of the pressure increase has a possibility that the length of Taylor wave behind the detonation wave becomes longer for the case of longer detonation tube.

著者

小粥 雅貴 若松 栄史 森永 英二 荒井 栄司 島田 茂樹 眞鍋 賢

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.80, no.814, pp.TRANS0141-TRANS0141, 2014 (Released:2014-06-25)

参考文献数

12

被引用文献数

1

---

In this paper, a prediction method of the maximum principal strain of a core/shielding wire contained in a coaxial cable, which is related to the life-cycle of the wire, is proposed. If the central axis of a wire is assumed to be twisted around a virtual cylindrical surface when a coaxial cable is straight and a virtual toroidal surface when the cable is bent, the shape of the wire can be described by the first and the second fundamental form of their surfaces in the differential geometry. The potential energy of the wire, which is bent, twisted, expanded, and/or contracted, is also formulated based on the differential geometry. Friction of the wire against the virtual surface is modeled as a virtual spring in the circumferential direction of the surface and its elastic energy is included in the total potential energy of the wire. Then, the stable shape of the wire can be computed by minimizing its total potential energy under geometric constraints. After that, the maximum principal strain is estimated from the shape of the wire. As a result of simulation, it was founded that a core wire is broken by bending fatigue before the shielding wire is if they have the same radius and rigidity.

著者

瀧下 謙一 米田 篤彦 清水 康夫

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.81, no.827, pp.15-00101-15-00101, 2015 (Released:2015-07-25)

参考文献数

4

---

In this paper, we focused on the fact that the ease of driving changed according to torsional rigidity of the electric power steering system for the purpose of the improvement in control performance of vehicle. First, the influence on transfer characteristics from a steering angle(steering wheel) to front wheel angle(front tires) by torsional rigidity was considered theoretically. As a result, it turned out that a front wheel angle was determined by not only a steering angle but also the influence of the dynamic state of vehicle, and it was shown that the influence of the dynamic state of vehicle can be shut by making steering torsional rigidity into high torsional rigidity. Next, the validity of a theoretical verification was confirmed through numerical simulation of steering correction at the time of a disturbance input. Finally, the lower limit value of torsional rigidity for practical use of a high torsional rigidity steering was determined.

著者

能美 亜衣 高橋 正樹

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.81, no.826, pp.14-00297-14-00297, 2015 (Released:2015-06-25)

参考文献数

12

被引用文献数

1

---

This paper proposes a design method of the fault-tolerant attitude control system for spacecraft. In recent years, there has been requirement for accurate and agile attitude control of spacecraft. To meet this demand there has been an increasing use of Control Moment Gyros (CMGs), which can generate much higher torque than reaction wheels that are used as conventional spacecraft actuators. Furthermore, it is important for attitude control systems to be fault-tolerant. In a conventional 4 CMGs system, the CMGs are placed in a pyramid mounting arrangement with a skew angle set to 54.74 degree. The maximum angular momentum of the CMG system is changed according to the skew angle. A suitable skew angle should be designed to consider normal and failure situations. Moreover, the suitable parameters of spacecraft attitude and CMG control systems are changed according to the skew angle. In the proposed method, the skew angle and the parameters of the control system are tuned simultaneously using a genetic algorithm. To verify the fault-tolerance of the proposed method, numerical simulations for the case when one CMG has failed are carried out.

著者

大場 啓介 長嶺 拓夫 森 博輝 佐藤 勇一

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.81, no.824, pp.14-00593-14-00593, 2015

---

This paper describes the investigations of the characteristic about the sound generation of a nose flute experimentally. The nose flute is attached to the upper part of a container. If air is passed to a nose flute, sound will occur. The volume of a container is changed and the generated sound is measured. The natural frequencies of an experimental device are calculated and we confirm that it is in agreement with frequency of sound generated in experiment. We show that nose flute is a unique musical instrument with the point that a nose flute has only an edge part and uses peoples mouth for a resonance body part. The frequencies of resonance sound can be calculated from the capacity in a mouth, the thickness and the area of an opening of a nose flute. When people play a nose flute, it is thought that only the first mode of vibration is used.

著者

鈴木 悟史 吉井 正広 中西 洋喜 山隅 允裕 小田 光茂 上田 敦史 渡邊 恵佑 加藤 裕基 星 亜友美 西田 信一郎

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.81, no.824, pp.14-00298-14-00298, 2015 (Released:2015-04-25)

参考文献数

15

被引用文献数

2

---

Image processing is one of the methods used to measure position/attitude for robot control and there are hopes that it can be applied to space robot missions, including REX-J (Robot EXperiment on ISS/JEM). The REX-J mission involves space robot locomotive function experiments using tethers by JAXA. Measuring the robot's motion accurately is crucial to establishing the new locomotive technology using tethers. With conventional methods, a suitable illumination environment is configured for high-precision image processing and a characteristic marker is attached to the measurement object. However, the two challenges posed for image processing during the REX-J mission are: (1) the illumination of space changes significantly with orbital motion and (2) the robot lacks a characteristic marker. Accordingly, our purpose is to develop a marker less image processing method for the illumination environment of space and measure the robot's position/attitude of the REX-J mission by image processing. The proposed new image processing method involves creating virtual points are created at the intersection of the robot's edge in the image, which are then used as markers for image processing. This method is robust for changes in the illumination environment because it allows the creation of a virtual point, even if the edge is incomplete. The method is applied to the REX-J mission and the measurement accuracy of the robot's position/attitude in the illumination environment of space was confirmed as on the sub-pixel level. Subsequently, the position/attitude of the robot during movement by tethers was measured by image processing. In addition, the error in the robot's position/attitude, as estimated from the length of the tethers, was clarified by the image processing result. Based on these results, the robot's locomotive function by the REX-J mission was verified.

著者

三輪 洋靖 渡辺 健太郎 福原 知宏 中島 正人 西村 拓一

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.81, no.822, pp.14-00207-14-00207, 2015 (Released:2015-02-25)

参考文献数

29

被引用文献数

1

---

Employees at nursing-care facilities co-operate with each other and provide nursing-care service according to care plans designed to meet residents’ physical condition and needs. Traditionally, improvement of service productivity in nursing-care service has been based on experience and inspiration of managers and employees. Engineering methods to achieve improvement is a relatively new and necessary approach. In this paper, the authors collaborated with eight nursing-care facilities, and developed engineering methods to achieve improvement of their service process and service productivity. At first, we classified employees’ behaviors into a three-layer structure consisting of “service type”, “purpose / situation” and “operation”, and developed task classification for nursing-care service which could express 455 employees’ states. We then described nursing-care service process as transition of employees’ state with eight properties; “id”, “start time”, “end time”, “task”, “place”, “target resident”, “cost” and “detailed information”. Finally, we measured behaviors of 20 employees at four nursing-care facilities to evaluate the task classification for nursing-care service proposed in this paper, and confirmed that it covered 96.9 % of their behaviors. The cover rate was enough high for visualization of nursing-care service process. In addition, we visualized the nursing-care service process of 15 employees at a nursing-care facility with “time-line mode” and “statistical mode”. We also confirmed that our proposed methods were effective to visualize the nursing-care service process and to improve service productivity in the service field.

著者

三浦 渉尊 嶋田 敏 緒方 大樹 太田 順 新井 民夫 原 辰徳

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.80, no.819, pp.DSM0336-DSM0336, 2014 (Released:2014-11-25)

参考文献数

18

---

Since service is an artifact as well as physical product, we can observe both function design and activity design of service in a conceptual design phase. Activity design requires designers to deploy all designed functions into activities in service delivery process. However, it is difficult for non-experienced designers to model complicated service delivery processes such as conditional branches and exception handlings while assuring the relationship to functions. To solve this problem, the authors propose a design support of constructing service delivery processes using a collection of structure patterns of processes called Workflow Patterns. In this paper, we make the Workflow Patterns hierarchized by the ISM method so that designers can easily choose a pattern among them according to purpose. The proposed method was implemented on a CAD system for service, and its effectiveness was verified through an evaluation experiment. As a result, it was revealed that the proposed method is especially effective in the case of constructing processes including conditional branches.

著者

中島 卓司 坪倉 誠 岡田 義浩 農沢 隆秀 溝兼 通矢 土井 康明

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.80, no.818, pp.FE0301-FE0301, 2014 (Released:2014-10-25)

参考文献数

13

被引用文献数

2

---

The objective of this study is to investigate aerodynamics and its generating mechanism of a road vehicle in steady-state cornering, which is the most basic cornering condition. The vehicle motion in the steady-state cornering was defined on a frame of reference fixed on the vehicle and it was divided into a rotation around a vertical axis and a sideslip. Then, aerodynamic force generated by each motion and its generating mechanism was discussed. In order to reproduce an effect of the rotational motion, a towing tank experiment was conducted to measure the fluid-dynamic force acting on a one-fifth-scale model of a sedan-type road vehicle. Assuming that the fluid-dynamic forces are expressible as a linear superposition of effects of the rotation and sideslip, first derivatives of the side force and yaw moment with respect to the yaw rate and the lateral velocity were analyzed by a multiple linear regression analysis. From the results of measurement and analysis, it was clarified that the assumption can provide good approximations of the force and the moment within a range of measurement conditions in this study. Regarding the fluid-dynamic side force, the rotation generates a centripetal force of the circular motion and the sideslip generates a force suppressing the slip motion. Regarding the fluid-dynamic yaw moment, the rotation generates a moment suppressing the rotation, and the sideslip generates a moment enhancing the vehicle's slip angle. Aerodynamics of a sedan-type road vehicle was estimated quasi-steadily by multiple regression equations with measured vehicle motion in an on-road test. From this estimation, the effects of both the rotation and the sideslip had the same order of magnitude. This result indicates that the effects of the vehicle's rotational motion have the same level of importance as the effects of the sideslip in vehicle aerodynamics in steady-state cornering.

著者

丸茂 喜高 清水 勇介 竹内 亮佑 綱島 均 小島 崇

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.80, no.817, pp.TL0280-TL0280, 2014

被引用文献数

1

---

This study proposes a driving assistance system to inform the notch operation timing for train drivers. The assistance system indicates visually the notch-off position where the driver releases the accelerator. The notch-off position is calculated by the present vehicle acceleration, velocity and position by assuming the constant acceleration. The assistance system also indicates the brake onset and the predicted stopping positions. Two experiments are conducted by using the train-driving simulator. One experiment examines the effects of the notch-off and brake onset timing on the vehicle velocity and the running time. The assistance system makes it possible to adjust the vehicle velocity and the running time. The other experiment examines the three running patterns by combination of the notch-off and the brake onset positions. With the time recovering pattern, which is combination of the higher notch-off velocity and the later brake onset timing, the assistance system realizes the shorter running time in comparison with the standard running pattern. With the energy saving pattern, which is combination of the lower notch-off velocity and the later brake onset timing, the assistance system prevents the time delay by the later brake timing even if the velocity is lower than the standard running pattern.

著者

森川 翔太 積際 徹 横川 隆一

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.80, no.816, pp.DR0234-DR0234, 2014 (Released:2014-08-25)

参考文献数

23

---

The objective of this study is to develop the wearable haptic device having widely operating range and highly efficient dynamic characteristics of the end-effector located on the tip of the haptic device. The conventional haptic device displays pseudo translational force to the operator's hand. However, there is a problem that the dynamic characteristics of the end-effector of these devices are restricted to the response of motion of the actuator. To improve the dynamic characteristics of the end-effector, the variable structure control which is able to choose either connection or disconnection between the actuator and the end-effector is developed. The proposed system controls (opens or closes) the hinge mechanism, so that the actuator and the end-effector can be connected or disconnected depending on the opened or closed status of the hinge mechanism. Accordingly, we develop the control system including the coordinate transformation of the displaying force using the angle sensor by taking into account large range of motion in the end-effector. To confirm the effectiveness of the proposed control method, experiments of force display for human operators were carried out. The experimental results show that the proposed system is able to improve the dynamic characteristics of the end-effector and to amplify the operating range of the hand motion in the force non-displayed condition.