著者

郭 鐘声 小竹 元基 鎌田 実

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.16-00092, (Released:2016-09-07)

参考文献数

20

---

In a bathing environment, it is needed to evaluate an emotional effect quantitatively and continuously at stage of the product design for improving stress-relaxation effect. This study aimed to propose an index which can evaluate the comfort quantitatively and continuously on bathing. To search the physiological indices correlated to the comfortable feeling, we measured subjective evaluation of comfortable feeling in one-minute increments, with continuous measurement of physiological parameter before bathing, on bathing, after bathing. We analyzed the relationship between time-series data of the subjective evaluation and the physiological parameter. As a result, we proposed the evaluation index of comfortable feeling by using HF content obtained from spectral analysis of heart rate variability, and confirmed that the evaluation index can evaluate comfortable feeling quantitatively and continuously including the effect of personal preferences related to bathing.

著者

村上 敬宜 高橋 宏治 山下 晃生

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.63, no.612, pp.1612-1619, 1997-08-25 (Released:2008-02-21)

参考文献数

21

被引用文献数

10 43

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In order to investigate the effect of surface roughness on fatigue strength, fatigue tests for a medium carbon steel, which was annealed and free of residual stress (HV≅170) and quenched and tempered (HV≅650). were carried out. To simulate the actual surface roughness, extremely shallow periodical notches with a constant pitch but irregular depth were introduced. The equivalent defect size √(area)R for roughness was defined to evaluate the effect of irregularly shaped roughness using the √(area) parameter model. The fatigue limits of the annealed medium carbon steel specimens with artificial surface roughness are much higher than those of the specimen with a single notch because of the interference effect of notches. The fatigue limits predicted by the √(area) parameter model are in good agreement with the experimental results.

著者

小出 祐一 中川 正紀 福士 直己 石垣 博邦

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.73, no.725, pp.66-71, 2007-01-25 (Released:2011-03-04)

参考文献数

9

被引用文献数

1 1

---

In vibration design, we need to estimate the damping ratio to calculate the dynamic response of a structure. In particular, an estimation of its probability distribution is important to carry out so-called probabilistic design. For this paper, we developed an estimation method using the Bayesian approach to generate the probability distribution of the damping ratio from a vibration test with a small sample size. The Bayesian approach has special significance to engineering design, where available test data is invariably limited, for the approach can systematically incorporate subjective judgments based on experience or indirect information with observed data. We supposed that the probability distribution of the damping ratio has a normal distribution. Therefore, we applied the Bayesian approach to estimate unknown parameters of the distribution. In addition, we compared this method with a method of moments classified as a classical estimation and investigated the influence of sample size by conducting an evaluation test. With the results of our analysis, we came to the following conclusions. First, he true standard deviation of the damping ratio is less than 0.4, and the prior distribution of the standard deviation ranges between 0 and 0.5. (1) The estimated probability distributions determined by the Bayesian approach and the classical approach almost fully agree across more than 40 specimens. (2) The Bayesian approach provides good agreement, less than 10 percent error, with a true standard deviation for approximately 10 specimens. Even though the prior distribution of standard deviation ranges between 0 and 1.0, almost the same accuracy is obtained for approximately 10 specimens.

著者

許 金泉 付 列東 武藤 睦治

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.68, no.672, pp.1266-1272, 2002-08-25 (Released:2008-02-21)

参考文献数

7

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The three dimensional theoretical solution of a normal concentrated forces on the free surface of a coating material is deduced by introducing the infinite mirror points of the load point and applying the Dirichlet's uniqueness theorem. The deduction is based on the basic equations of the spatial axisymmetric problems. It is found that all the stress functions corresponding to the mirror points, which satisfy the continuous conditions at the interface and the free boundary conditions at the free surface, can be deduced from the fundamental solution of a concentrated normal force on the free surface of a semi-infinite homogeneous solid. It is also found that only the stress functions corresponding to the first few mirror points have an influence on the accuracy of the theoretical solution. It is also found that the effect of material combination cannot be expressed by Dunders' parameters only. The stress field can be described by using Dunders' parameters together with the additional parameter.

著者

淺井 裕斗 村田 滋 田中 洋介

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.823, pp.14-00348-14-00348, 2015 (Released:2015-03-25)

参考文献数

11

---

This paper presents a normalized deconvolution approach for a digital holographic particle measurement in order to decrease the elongation of the reconstructed particles along the depth direction. The performance of this approach is evaluated using numerical simulations, and its practicality is experimentally demonstrated. In the numerical simulations, the performance is evaluated mainly based on the cross-correlation between the true distribution and the deconvolution results. Tests were carried out for two types of recording systems and three kinds of reconstructed information. The results indicate that the most accurate particle images were obtained using the phase-shifting observation method and reconstructed quantities that contain phase information, such as the complex amplitude. Furthermore, the RMS error in the particle depth position is found to be improved especially for higher number density within the particle distribution. Experimental measurements with standard particles confirm that particle elongation along the depth direction can be successfully suppressed using the normalized deconvolution method. The experimental results thus confirm that this method is useful for real particle measurements.

著者

Yoshitaka NAKAO Hiroshi NAGAMOCHI

出版者

一般社団法人 日本機械学会

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.1, no.2, pp.217-226, 2007 (Released:2007-04-27)

参考文献数

12

被引用文献数

2 13

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We consider a discrete-type split delivery vehicle routing problem, in which delivery goods for a customer consist of a set of items, each item is required to be serviced by exactly one vehicle, and each customer is allowed to be visited more than once. In this paper, we propose a fast algorithm that constructs a set of routes one by one without any improvement procedures. The algorithm generates routes by dynamic programming based on an elaborate route evaluation function that estimates the total travel cost required to service all the remaining items by vehicles. Experimental results on real-world instances are reported.

著者

木村 弘之

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.837, pp.15-00535-15-00535, 2016 (Released:2016-05-25)

参考文献数

13

被引用文献数

2 2

---

When an elevator rope for a high-rise building is forcibly excited by the displacements of the building induced by wind forces and/or by long-period ground motion, rope displacement becomes large even if the ground acceleration and the buildings acceleration are small. In previous paper, when elevator cage is stationary, a new practical method for reducing the rope vibration by using vibration suppressors is proposed for relaxing the restricted elevator operation. The advantage of using the vibration suppressors for reducing the rope lateral vibration is demonstrated through numerical calculation. Further, when arbitrary position of the rope is pulled, exact solution to the free vibration of the rope with vibration suppressor, which located at the center of the rope and the gap between rope and vibration suppressor is 0, has been presented. However, in the case where the position of vibration suppressor is center of the rope and the gap between rope and vibration suppressor is not 0, no exact solution to the free vibration has yet been obtained. In this paper, an exact solution to the free vibration of this case is presented. In the analysis, the rope is modeled with string. Finite difference analyses of the rope vibration with vibration suppressor are also performed to verify the validity of this exact solution. The calculated results of the finite difference analyses are in fairly good agreement with those of the exact solution.

著者

森 和也 陳 玳〓 西谷 弘信

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.57, no.544, pp.2987-2991, 1991-12-25 (Released:2008-02-21)

参考文献数

8

---

The authers have developed a method for satisfying resultant boundary conditions on each divided boundary by discrete point forces. This method stands high accuracy and short calculating time at the same time. However, to obtain highly accurate solutions, it is necessary to put the point forces at the optimum locations. In this paper, the optimum location of point forces were obtained through several problems in 2D or 3D. The optimum location, that is, the optimum ratio of devided boundary length to distance between point force and boundary is 0.5∼0.7 in the case of notch problems and is 1.5 in the case of crack problems.

著者

Saran KEERATIHATTAYAKORN Satoshi YAMADA Shigeru TADANO

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.15-00423, (Released:2015-09-07)

参考文献数

27

被引用文献数

1 1

---

The authors proposed an electromyography computed tomography (EMG-CT) method to measure the distribution of muscle activity in the forearm using surface EMG signals from multiple surface electrodes. The present study is to develop a method to estimate muscle stress, i.e., force generated during contraction per unit area in the whole cross-section of the forearm based on EMG-CT. While three subjects performed hand gripping trials using three hand grip devices, EMG signals around the forearm were measured using EMG-CT. An EMG conduction model of the forearm was constructed using an outline geometry of the subjects' forearm which was measured with a handy 3D scanner. The stress of muscle was calculated from the relationship between gripping force and total muscle activity. As a result, the distribution of muscle stress in the forearm during hand gripping was visualized in a tomographic image. It was clear that the stress was concentrated in the flexor digitorum superficialis, flexor digitorum profundus, flexor carpi radialis, and extensor digitorum communis region. The maximum stress in the forearm muscles increased from 0.08 ± 0.01 to 0.18 ± 0.02 MPa when gripping force increased from 77 to 242 N. This study provides a novel method of measuring muscle stress in forearm.

著者

田中 純夫 平島 健一 広瀬 幸雄 MURA Toshio

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.58, no.549, pp.745-752, 1992-05-25 (Released:2008-02-21)

参考文献数

11

---

This paper presents an analysis of in-plane problems for isotropic semi-infinite body due to single force, single dislocation, dipole-force, dipole-dislocation, and so forth, with various surface boundaries such as free, fixed and two sliding conditions. Distributions of stresses and displacements under applied singular forces for the above four boundaries are illustrated by some graphical representations as numerical examples.

著者

阿部倉 貴憲 森下 進悟 山本 毅 杉浦 昇 稲垣 瑞穂

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.837, pp.15-00615-15-00615, 2016 (Released:2016-05-25)

参考文献数

14

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As vehicle engines become lighter, smaller, and more powerful, stress prediction of the main bearings has become an important aspect of strength design measures for the cylinder block. To predict the stress of the engine main bearings under actual working conditions, a flexible multibody dynamics (FMBD) solver was developed with a built-in elastohydrodynamic lubrication solver for the main bearings. The dynamic behavior of the engine system under actual working conditions was then calculated and the results were used to calculate the stress. To reduce the stress calculation cost, rather than inputting the actual working load into a finite element model (FEM) of the whole engine as a boundary condition, the stress was calculated by inputting the dynamic behavior into a small FEM consisting only of the main bearing as a displacement boundary condition. Verification of the test results confirmed that this model is capable of highly precisely predicting the actual working strain of main bearing portions susceptible to fatigue-related fractures. It was confirmed that the developed model could predict the actual working strain if the highest natural frequency of the eigenmode utilized by the FMBD analysis was set to 50kHz or higher.

著者

岡 正徳 都井 裕

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A編 (ISSN:18848338)

巻号頁・発行日

vol.79, no.806, pp.1411-1421, 2013 (Released:2013-10-25)

参考文献数

18

被引用文献数

1 1

---

The elasto-viscoplastic-creep constitutive equation based on the concept of continuum damage mechanics is formulated for the gray cast iron as used in diesel engine parts. It employs the viscoplastic strain given by Chaboche-Rousselier and the creep strain given by Perrin and Hayhurst. A part of the material parameters contained in the creep constitutive equation which was previously identified by Oka and Toi are assumed to be temperature-dependent in the present study. The identified model is applied to the creep fatigue life prediction of the cylinder head used in diesel engine parts which is made of gray cast iron. Although there are some points to be improved, the validity of the proposed model is illustrated by comparing the calculated results with the experimental results for the crack initiation locations and the crack propagation directions.

著者

小松崎 俊彦 岩田 佳雄

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C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.786, pp.420-430, 2012 (Released:2012-02-25)

参考文献数

10

---

In this study, a virtual sound production system is developed where the difference frequency component appears as the secondary audible sound at a point of interference locally by the nonlinear interaction of two independently radiated ultrasounds while they travel directionally and intersect each other. The design of high-directive ultrasonic radiator, followed by the investigation of virtual sound production performance has been done theoretically as well as experimentally. It is known from these investigations that the fairly local sound reproduction in free space is possible, yet the sound pressure level of the secondary field is small. The results have also shown that the generated virtual sound area is dependent on both the difference frequency and the intersection angle of two carrier waves emitted by two sound sources.

著者

斉藤 俊 千葉 洋三

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.64, no.623, pp.2389-2394, 1998-07-25 (Released:2008-02-26)

参考文献数

10

---

Two kinds of road racer bicycles are employed to research vibration characteristics of driving bicycles. After obtaing the natural frequencies and modes by vibration test in the non-driving state, practical driving tests are carried out. The acceleration of vibration in the middle of the handles and under the saddles are measured and the corresponding spectral density functions are calculated based on FFT method. The results show that in the driving bicycles, the dominant frequencies exist between 10 Hz and 50 Hz and the lower two modes in the non-driving state are excited.

著者

Masahiro KANAZAKI Shoma ITO Fumio KANAMORI Masaki NAKAMIYA Koki KITAGAWA Toru SHIMADA

出版者

一般社団法人 日本機械学会

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.11, no.1, pp.JFST0003-JFST0003, 2016 (Released:2016-02-17)

参考文献数

8

被引用文献数

1

---

This paper reports on the conceptual design of a three-stage launch vehicle (LV) with a clustered hybrid rocket engine (HRE) through multi-disciplinary design optimization. This LV is a space transportation concept that can deliver micro-satellites to sun-synchronous orbits (SSOs). To design a high-performance LV with HRE, the optimum size of each component, such as an oxidizer tank containing liquid oxidizer, a combustion chamber containing solid fuel, a pressurizing tank, and a nozzle, should be determined. In this study, paraffin (FT-0070) is used as a propellant for the HRE, and three cases are compared: In the first case, HREs are optimized for each stage. In the second case, HREs are optimized together for the first and second stages but separately for the third stage. In the third case, HREs are optimized together for each stage. The optimization results show that the performance of the design case that uses the same HREs in all stages is 40% reduced compared with the design case that uses optimized HREs for each stage.

著者

岩崎 晃久 猫本 善続 森田 英之 谷口 勝彦 奥野 大作 松岡 寿浩 千種 直樹

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.831, pp.15-00212-15-00212, 2015 (Released:2015-11-25)

参考文献数

18

---

Under earthquake condition, the response of the free standing rack is nonlinear and involves complex combination of motion, such as sliding, rocking, twisting, and impacts between the fuel assemblies and the rack cells and between the pool floor and the rack pedestals. To obtain an accurate simulation of the free standing rack, the seismic analysis requires careful considerations of these complex phenomena, and fluid coupling effects. This seismic evaluation method was validated by comparison to full-scale test results. However, the conservative evaluation method is required, since analysis results are not entirely consistent with the test results. In this study, authors obtained the margin of safety for free standing rack, and developed the seismic design method.

著者

永井 裕二 村松 幸治 小林 信之 鳥阪 綾子

出版者

一般社団法人 日本機械学会

雑誌

年次大会

巻号頁・発行日

vol.2012, pp._S102014-1-_S102014-5, 2012

---

Vibration modes measurement and an analysis method on the partially stiffened cylindrical shell with attached mass which contains liquid partially in it, were developed. Since it was measured that the harmonic numbers of circumferential vibration modes of the liquid filled lower part is different from that of the empty upper one, a finite strip method, which is taken into account the geometrical stiffness of hoop stress due to the contained liquid, partial mass and stiffness by attached elements, was developed. As a result, experimental natural frequencies that the harmonic numbers changes along axis are good agreement to those by analysis.

著者

伊達 央 大川 真弥 滝田 好宏 菊地 惇

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C編 (ISSN:18848354)

巻号頁・発行日

vol.79, no.806, pp.3389-3398, 2013 (Released:2013-10-25)

参考文献数

11

被引用文献数

2 11

---

This paper presents the technique for improving the accuracy and reliability of an autonomous mobile robot localization. Localization based on 2D LIDAR is not always satisfactory due to occlusion. Use of 3D LIDAR improves the reliability by greater field of view. However, lack of 3D objects around the robot may result in poor matching between the observation and the 3D map. Even in this case, the different brightness of the ground surface helps localization. In this paper, we propose an efficient expression of 3D map by considering of LIDAR intensity. Experiment result shows successful localization in a trail through outdoor open grass fields.

著者

飯田 明由 小久保 あゆみ 塚本 裕一 本田 拓 横山 博史 貴島 敬 加藤 千幸

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.73, no.732, pp.1637-1646, 2007-08-25 (Released:2011-03-03)

参考文献数

10

被引用文献数

4 1 7

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The aim of this investigation is to understand the generation mechanism of aero-acoustic feedback noise radiated from rear-view mirrors. In order to clarify the relationship between the velocity fluctuation and radiated noise, correlation in terms of aerodynamic noise and velocity fluctuations were measured in a low-noise wind tunnel. The experimental results showed that noise level of the tonal-noise depended on the ratio of the height of the bump to the thickness of the boundary layer. Strong tonal-noise was generated when the height of the bump was almost equal to 40% of the height of the boundary layer. The tonal-noise level also depended on the length between the trailing-edge of the bump and the edge of rear-view mirror. The frequency of the tonal noise can be calculated by modified Rossiter equation. The tonal-noise was disappeared in the case of the bump was placed at separated boundary layer. It revealed that the seed of the tonal noise was small disturbances generated by the bump on the surface of the rear-view mirror.

著者

江口 譲 杉本 聡一郎 服部 康男 平口 博丸

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.823, pp.14-00478-14-00478, 2015 (Released:2015-03-25)

参考文献数

15

被引用文献数

1

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Explanation is given about a rational method to evaluate tornado-borne missile speed, flight distance and flight height to be used for safety design of a nuclear power plant. In the method, the authors employed Fujita's DBT-77 model as a tornado wind model to take the near-ground tornado wind profile into account. A liftoff model of an object on the ground was developed by conservatively modeling the lift force due to ground effect. The wind field model and the liftoff model have been compiled together with a conventional flight model into a computer code, named TONBOS. In this study, especially, the code is verified for one- and two-dimensional free-fall problems as well as a case of 1957 Dallas tornado wind field model, whose solutions are theoretically or numerically known. Finally, the code is validated by typical car behaviors characterized by tornado wind speeds of the enhanced Fujita scale, as well as by an actual event where a truck was blown away by a tornado which struck a part of the town of Saroma, Hokkaido in November, 2006.