著者

感本 広文 中司 雅文

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.14-00676-14-00676, 2015 (Released:2015-04-25)

参考文献数

13

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Spent nuclear fuel assemblies are stored in the cask with the necessary protective function during the spent fuel transportation or storage. The structural integrity of the fuel rods for the impact load caused by cask mishandling drop accident has to be evaluated to realize more economical and safe operation. However, the experiments for the spent fuel rods accompany many of difficulties and the available experimental data is limited. Hence, the numerical simulation is useful method to predict and evaluate the dynamic response of the fuel rods. This paper deals with the dynamic response of the spent fuel rods under side drop condition. One spacer span of the fuel rod of the undermost layer during side drop is analyzed by finite element method (LS-DYNA). The fuel rod was held between the upper and lower spacers. In the numerical model, the fixed rigid base and the drop weight were connected to the lower and upper spacers, respectively. The numerical analyses were carried out by varying the impact speed of the drop weight and the spacer plate size. Further, the cases of entire drop, in which both the drop weight and fuel rod have the same impact speed, and weight drop, in which only the weight collides with the spent fuel rod placed on the rigid wall were also analyzed. It is found that the fuel pellet and cladding tube reached their yield stresses near the impact point even for the lowest impact speed (2.4m/s) regardless of the spacer size and drop conditions. The plastic region of the pellets is limited within one pellet and the corner part of the neighboring pellet even for the highest impact speed (13.3m/s). The deflection of the fuel rod increased from impact point to the end of the fuel rod in the entire drop condition, but it was limited near the impact point in the weight drop condition. Therefore, the weight drop condition may underestimate the deformation or damage of the spent fuel rod compared to the entire drop condition.

著者

今荘 和也 巽 和也 Winoto Sonny H. 中部 主敬

出版者

一般社団法人 日本機械学会

雑誌

年次大会講演論文集

巻号頁・発行日

vol.2009, pp.137-138, 2009

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Microvalves are the essential parts of valveless micropumps and other integrated microfiudic systems. The non moving parts (NMP) valve of which geometry is fixed is a simple and reliable valving concept. This paper proposes R type valve as the improved form of 'Tesla valve' which is one of the NMP valves, and evaluated its performance numerically. In the R type valve case, diodicity was 1.37 at Re = 500 and 14% more efficient than the optimized Tesla valve. In addition, the flow characteristics of pulsating flow in low Re regime was different from those of steady flow with the identical instantaneous Re conditions.

著者

設樂 真理子 宮 瑾 芹澤 凌 牧野 真人 西岡 昭博 古川 英光

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.829, pp.15-00008-15-00008, 2015 (Released:2015-09-25)

参考文献数

5

被引用文献数

2

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The market of care food is growing for aging society and the personal version of care food will be needed for improving a fun of meal. On this occasion, 3D printing technologies have been developed and are being applied for food creation. In the present study, we prepare food ink for the world-first 3D gel printer designed by our group. The hardness of food is one of the most important factors that influence the texture of food. So that the jelly foods made by the 3D gel printer is designed being soft and easy to chew. Here four kinds of jelly food samples are prepared by using agar and gelatin as gelation agents. The mechanical strength of the jelly foods is evaluated by a compression test for foods. We measured the hardness (maxmum stress) of the jelly foods and succeeded in the preparation of various jelly foods of 8 ~ 45kPa in hardness. The gelation of agar is possibly controlled by temperature change. Thus by using the temperature change, the jelly foods are easily printed by the 3D gel printer. We hope these printed jelly foods will make it possible for elder persons to enjoy their fun of everyday meal and improve the quality of life for the elder persons.

著者

小堺 孝和 加藤 裕之 中北 和之 金崎 雅博

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.15-00188, (Released:2015-08-20)

参考文献数

13

被引用文献数

1 1

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The “buffet” which is the shock wave vibration on the wing at transonic speed has influence to the aerodynamic performance of the civil transport. It is significant because the wing cannot maintain its aerodynamic performance and it is also led to the stall. Therefore, several researches on the suppression of the buffet are carried out. A Vortex Generator (VG) is one of the way which can improve to the transonic buffet. It is simple device and widely applied to the commercial airplane. Conventionally, VGs are installed along the wing span. However, they increase the friction and the instruction drag. Thus, the number of VGs should not be beyond the minimum necessary. Another problem is that it is still expensive for the computational fluid dynamics to simulate the small size vortex accurately. Therefore, the optimization procedure of the VGs installation is developed with directly combining the wind tunnel evaluation result. To reduce the number of experimentations, the surrogate model based GA exploration is employed. The design objective is to maintain the linearity of the variation lift with changing angle of attack (lift curve), because the stall is appeared if the curvature of the lift curves become smaller. Eight initial designs are evaluated and five design samples are acquired. As this result, optimum samples can be explored with reducing the number of the experiment. Several samples successfully prevent the stall without increasing the drag. In addition, the design knowledge can be obtained regarding the optimum VG’s layout by visualization.

著者

伊達 直輝 坂東 麻衣 外本 伸治

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 (ISSN:21879761)

巻号頁・発行日

vol.81, no.826, pp.14-00657-14-00657, 2015 (Released:2015-06-25)

参考文献数

16

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As low-thrust propulsion technology becomes increasingly popular, orbital estimation for low-thrust spacecraft may become an area of increasing interest. More frequent use of low-thrust propulsion to place satellites in orbit gives more opportunities for collisions and radio frequency interference as these spacecraft travel slowly through altitude ranges. The purpose of this paper is to develop a method for estimation of the osculating orbital elements for low-thrust spacecraft. To overcome the instability of the estimation problem with low-thrust acceleration, we estimate the mean elements instead of osculating elements. By use of the averaging technique, Hudson and Scheeres proposed an analytical model of secular variations of orbital elements under thrust acceleration. The resulting averaged equation has a nice property in which only a finite number of Fourier coefficients of the thrust acceleration appear because of the orthogonality of the trigonometric function. Based on the nonlinear state equation representation for the extended state variables which include not only orbital elements but also unknown Fourier coefficients, mean orbital elements and thrust history are estimated from perturbed observation data of mean orbital elements. Then, the mapping from mean to osculating elements which is derived from the perturbation theory is used to estimate the osculating elements. The proposed method is demonstrated through numerical simulations.

著者

伊達 直輝 坂東 麻衣 外本 伸治

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 (ISSN:21879761)

巻号頁・発行日

vol.81, no.826, pp.14-00487-14-00487, 2015 (Released:2015-06-25)

参考文献数

15

被引用文献数

1 1

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Space Situational Awareness (SSA) has been recognized to be important for safe space activities. As low-thrust propulsion technology becomes increasingly popular, SSA for low-thrust spacecraft may become an area of increasing interest. In this paper, we propose an orbital estimation method to predict the long-term evolution of spacecraft trajectory under unknown low-thrust acceleration. In particular, by the use of the perturbation theory and a nonlinear Kalman filter, long-term variations of orbital elements and thrust accelerations can be estimated from observation data of mean orbital elements. Performance of our method are evaluated for both controlled and uncontrolled orbits.

著者

中村 友道 廣田 和生 友松 健一 高井 睦夫 岩瀬 敏彦 宇和川 誠一 班目 春樹 岩壺 卓三 齋藤 孝基

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.68, no.668, pp.1064-1072, 2002-04-25 (Released:2008-02-26)

参考文献数

7

被引用文献数

1 1

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A partial but full-size mock-up test of practical steam-generator U-bend tubes in nuclear power plants has been carried out, where the test model has been set in a HFCF-123 fluid two-phase flow loop. U-bend tubes are supported with so-called "Anti-vibration Bars (AVB) ", which have two types of AVBs in Japan, 7-span type and 5-span one. Both types of AVBs have been examined and it is found that tubes with AVB supports shows no large amplitude vibration up to 150% flow rate to the practical condition. Basic data for the fluidelastic instability are obtained when some tubes have been set to be flexible at some contact points with AVBs.

著者

相場 一希 大宮 正毅 射手矢 岬 紙谷 武 戸松 泰介

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A編 (ISSN:18848338)

巻号頁・発行日

vol.78, no.796, pp.1631-1641, 2012 (Released:2012-12-25)

参考文献数

16

被引用文献数

2

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Beginning in 2012, judo has been selected to be a compulsory course in junior high schools in Japan. However, the number of participants, in particular beginners, who die or are injured in judo is higher than that for other sports. For this reason, there is a fear that there will be a drastic increase in the number of judo-related accidents leading to death or injury in junior high schools. The most serious form of head injury is acute subdural hematoma (ASDH). The purpose of the present study is to compare ASDH occurrence indices and to evaluate the effectiveness of using head protectors. Based on measurements of head acceleration during falling, the Head Injury Criterion (HIC), maximum angular acceleration and angular velocity variation range were calculated. The results indicated that the relative displacement between the brain and skull was most strongly correlated with the angular velocity variation range, which is thus a candidate evaluation index for ASDH. The results also suggest that in order to prevent ASDH, a head protector should be made of shock absorbing materials with a small coefficient of restitution, so as to reduce the rebound velocity of the skull after occipital impact.

著者

森西 洋平 福井 岳人

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.75, no.759, pp.2163-2172, 2009

参考文献数

19

被引用文献数

2

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A non-segregated numerical algorithm is proposed for unsteady incompressible flow simulations with the fully discrete fully conservative finite difference scheme. The fully conservative finite difference scheme is useful for the numerical simulations of unsteady turbulent flow because of its stability and reliability. However, a large system of nonlinear discrete equations should be solved for the fully (spatio-temporal) discrete fully conservative scheme. In this study, the Jacobian-Free Newton-Krylov (JFNK) method with the GMRES(m) method as a Krylov iterative solver is introduced as a non-linear solver in the non-segregated numerical algorithm. A couple of preconditionings to the Krylov iterative method are tested and a new effective physical-based preconditioning is proposed. Numerical tests on the DNS of turbulent channel flow demonstrate the availability of the present method. Then, the DNS of backward facing step flow is carried out for an example of a stiff problem in which the streamwise grid spacings are locally fine.

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

pp.14-00478, (Released:2015-02-04)

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.

著者

西本 哲也 望月 康廣

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.13-00729, (Released:2015-01-14)

参考文献数

26

被引用文献数

1

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The aim of this study was to examine micro injuries of brain tissue to gain a better understanding of head injury tolerance. Compression stress relaxation experiments were conducted in vitro, using porcine brain tissue and subsequently analysed using two stain methods; immunofluorescent stain and immunoenzymatic stain. In these in vitro stress relaxation experiments, brain specimens were compressed quasi-statically at 1 mm/s, for compression strains ranging from 10% to 50%, in ten percent increments. Using the immunofluorescent stain method, it was observed that axon tear occurred at a compression strain of 30% or greater. The distribution of the damage ratio of the transverse length to the longitudinal length of brain nerve cells (referred to as an aspect ratio) using immunoenzymatic stain method in the brain tissue under loading was also examined. This indicated that at a compression strain of 30% or greater the aspect ratio exceeded 2.0. The results of this study show that a compression strain of 30% corresponds to the threshold for the extreme aspect ratio of 2.0; where the transverse length of deformed nerve cell is two times greater than longitudinal length.

著者

清水 昭比古

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:00214728)

巻号頁・発行日

vol.112, no.1090, pp.763-765, 2009

著者

能見 公博

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

vol.80, no.817, pp.SE0282-SE0282, 2014 (Released:2014-09-25)

参考文献数

12

被引用文献数

2 4

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This paper describes evaluation analysis for the space verification experiment of a tethered space robot on the sounding rocket "S-520-25." The S-520-25 rocket was launched on August 31, 2010. The tether was extended and kept its tension, and attitude control of the tethered space robot was performed. However, experimental results included non-linear dynamic motion, though the attitude control is designed under assumption of linear motion. Then, the space experimental results have been examined by mechanical dynamics software ADAMS. Non-linear motion can be evaluated qualitatively by simulation, and effectiveness of the attitude control has been confirmed.

著者

高野 敦 松林 三和子 松田 淑男 高野 千尋 小畑 貴稔 森川 洋

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.801, pp.682-690, 2013 (Released:2013-05-25)

参考文献数

22

被引用文献数

1 1

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A high strength bolt fastening system for satellite structures has been developed. This fastening system enables high frictional strength by adopting titanium bolts with high strength and low torque-coefficient, as well as shims with high friction coefficient. Low torque-coefficient of the titanium bolts is achieved by PTFE (Polytetrafluoroethylene) solid-film lubricant, which is coated on the bolts. High friction coefficient of the shim is achieved by surface roughening by etching. To verify the design of the fastening system, long-term preload test, torque-coefficient test and vibration loosening test (Junker's test) were conducted and successfully completed. In addition, the fastening system was applied to a development model of satellite structure and was verified by mechanical environmental tests (static load test, system vibration test and thermal vacuum test). The observation showed no evidence of slip or alignment deviation. Thus, a conventional reamer-bolted-fastening system can be replaced with the developed high strength bolt fastening system that saves manufacturing period of satellites and furthermore enables the satellites to be competitive in terms of cost, delivery and performance.

著者

高野 敦 松林 三和子 松田 淑男 小畑 貴稔 森川 洋

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.804, pp.1201-1209, 2013 (Released:2013-08-25)

参考文献数

13

被引用文献数

1 2

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Long-term measurement and prediction for Ti-6Al-4V and A286 bolts was conducted. It was pointed out that Ti-6Al-4V indicates significant creep behavior and accumulated large creep strain and thus Ti-6Al-4V can not be applied for preloaded bolts. In addition, preload relaxation due to creep of solid-film lubricants for bolts and fastened aluminum parts were also pointed out. Recently, the authors developed a high strength bolted fastening system for satellite structures with PTFE (polytetrafluoroethylene) solid film lubricated Ti-6Al-4V bolts and aluminum threadedand drilled-hole parts. The authors, hence, measured the preload of the fastening system for 253-days, predicted 30-years later preload, and confirmed that the preload reduction was not harmful.

著者

大島 裕子 足立 渡 辻内 伸好 小泉 孝之

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C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.796, pp.3947-3958, 2012 (Released:2012-12-25)

参考文献数

17

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In this paper, local polynominal regression is proposed as a metamodel for the optimal design. Local polynominal regression is often used for smoothing. Smoothing and approximation are applied for the different purpose, however these two methods are based on the similar theory. Therefore local polynominal regression is forecasted to be able to approximate functions. So the theory of local polynominal regression is extended to multivariate predictors for optimal design, and its effectiveness for approximation is verified. Next, more suitable optimization method that uses characteristics of local polynominal regression is suggested. Additionally, the comparison of local polynominal regression and other metamodels shows its features. As a result of the consideration, next four points are clarified. (1)LOESS that uses local quadratic regression and tricube weight function is most suitable for the approximation. (2)The metamodels based on local polynominal regression are able to use for the structural optimization and its characteristics are available for the optimization based on the gradient. (3)The accuracy of local polynominal regression is better than Kriging and RBF interpolation when the sample size is small. However, the property is reversed when the sample size is large. (4)The accuracy of local polynominal regression is better than Kriging and RBF interpolation when the response has noises. The fact shows local polynominal regression is suitable for the metamodel of montecarlo simulations and experiments.

著者

有田 隆一 加瀬 篤志 大場 謙吉

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:18848346)

巻号頁・発行日

vol.77, no.775, pp.823-831, 2011 (Released:2011-03-25)

参考文献数

5

被引用文献数

3

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The purpose of this research is to elucidate the mechanism of aerodynamic force generation and control in flapping flight of a mosquito. In this paper, a tenfold enlarged realistic model of the flapping wing was used to simulate the motion of the mosquito's wing and flow pattern around it. Experiments were conducted using a very low speed wind tunnel to coincide the condition of Reynolds and Strouhal numbers with those of real mosquito. The flow field around the wing model was analyzed by a stereo-PIV system. The aerodynamic forces generated by the model wings were calculated by using a momentum conservation law applied to the flow field. In these experiments, two unsteady ring vortexes around model wings were observed. The magnitude and direction of the jet flow induced by the ring vortex were greatly influenced by the attack angle. It was found that the lift was generated during the down-stroke and the thrust during the up-stroke in the real mosquito's flight.

著者

長谷川 裕晃 大津 里実

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B編 (ISSN:18848346)

巻号頁・発行日

vol.77, no.783, pp.2049-2057, 2011 (Released:2011-11-25)

参考文献数

20

被引用文献数

1

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The reverse osmosis (RO) method is a method obtaining the fresh water by using semi permeable RO membrane. However, the RO method has to give continuous operation at high pressure in seawater desalination plants. In the present study, in order to improve the efficiency of RO desalination under low pressure conditions, the water treatment system is proposed by using microbubbles in salt water disposal. Microbubbles are very small air bubbles with diameters of the order of less than several tens microns, and our proposed microbuble generator was developed in our previous study. The RO desalination efficiency can be improved by microbubble generation in salt water in contrast to the method with no microbubbles, and the efficiency of desalination is significantly improved by microbubbles with a high electrical potential. The effect of the microbubbles on the rate of osmosis was also investigated by measurements of the electric conductivity and the shrinkage rate of microbubbles. The electrical conductivity of salt water decreases with increasing the electrical property of the gas-water interface (ζ- potential) of microbubbles. Furthermore, microbubbles with a high electrical potential of high number density in salt water can exist in salt water because the rising velocity and the shrinkage rate of microbubbles become smaller with increasing the high electrical potential of microbubbles.

著者

平沼 賢次 川名 優孝 刑部 真弘 木船 弘康 毛利 邦彦 犬飼 和具

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:18848346)

巻号頁・発行日

vol.79, no.799, pp.234-238, 2013 (Released:2013-03-25)

参考文献数

2

被引用文献数

2

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This paper describes on the energy saving experiment by using the smart meter. In Japan, last summer, the power shortage was concerned and the limited use of electric power had been issued from the government. We constructed display system of the electric power consumption of Tokyo University of Marine Science and Technology (TUMSAT) on the web. This system could provide the average power usage during 10 minutes to promote the energy saving actions of each consumer. From the energy saving experiment in our university, it was found that the display on web was significantly effective to suppress the consumption of electric power without the compulsory cut off.

著者

Kenji KAWAGUCHI Tomoaki UCHIYAMA Ken MURAMATSU

出版者

一般社団法人 日本機械学会

雑誌

Journal of Power and Energy Systems (ISSN:18813062)

巻号頁・発行日

vol.6, no.3, pp.378-393, 2012 (Released:2012-08-10)

参考文献数

25

被引用文献数

10

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Fault Tree and Event Tree analysis is almost exclusively relied upon in the assessments of seismic Core Damage Frequency (CDF). In this approach, Direct Quantification of Fault tree using Monte Carlo simulation (DQFM) method, or simply called Monte Carlo (MC) method, and Binary Decision Diagram (BDD) method were introduced as alternatives for a traditional approximation method, namely Minimal Cut Set (MCS) method. However, there is still no agreement as to which method should be used in a risk assessment of seismic CDF, especially for uncertainty analysis. The purpose of this study is to examine the efficiencies of the three methods in uncertainty analysis as well as in point estimation so that the decision of selecting a proper method can be made effectively. The results show that the most efficient method would be BDD method in terms of accuracy and computational time. However, it will be discussed that BDD method is not always applicable to PSA models while MC method is so in theory. In turn, MC method was confirmed to agree with the exact solution obtained by BDD method, but it took a large amount of time, in particular for uncertainty analysis. On the other hand, it was shown that the approximation error of MCS method may not be as bad in uncertainty analysis as it is in point estimation. Based on these results and previous works, this paper will propose a scheme to select an appropriate analytical method for a seismic PSA study. Throughout this study, SECOM2-DQFM code was expanded to be able to utilize BDD method and to conduct uncertainty analysis with both MC and BDD method.