Nihon kikai gakkai ronbunshu最新文献

{"title":"Molecular dynamics analysis for the effect of the wettability and the slip on the solid wall surface on bubble growth","authors":"Souta KAKAMU, Takahiro ITO, Yoshiyuki TSUJI","doi":"10.1299/transjsme.22-00320","DOIUrl":"https://doi.org/10.1299/transjsme.22-00320","url":null,"abstract":"Since the boiling heat transfer is much affected by the nucleation of bubble and its growth, estimation of such process is essential for the accurate prediction of the heat transfer. In this study, molecular dynamics simulations were performed in order to clarify the effect of the wall conditions, i.e. the wettability and the slip between fluid and solid wall, on the bubble growth. The simulation results show that the evaporation near the contact line is enhanced and the vapor jet from contact line is observed. The direction of the vapor jet from the contact line is along the solid wall surface in the case of large slip and is along the liquid-gas interface in the case of small slip. The difference in the direction of the vapor jet is due to the flow in the adsorption layer on solid wall surface (in solid-gas interface). In the case of large slip, the fluid molecules in the adsorption layer flow with larger velocity in the direction away from the contact line. The vapor jet thus can develop along the surface of the adsorption layer. In the case of small slip, by contrast, the flow in the adsorption layer is prevented by the wall shear stress and the layer held on the wall surface invokes shear stress between the layer and the vapor jet. Consequently, the slip affects the vapor jet from contact line.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"慣性センサを用いた水平加速度の積分に基づく歩幅推定","authors":"Ryoga NAKANISHI, Motomichi SONOBE, Kiyoshi HIROSE","doi":"10.1299/transjsme.23-00194","DOIUrl":"https://doi.org/10.1299/transjsme.23-00194","url":null,"abstract":"The variation in stride length is an important index of gait stability. The evaluation requires a device that can accurately measure the stride length during ground walking. However, there are currently no practical and reliable measurement systems for clinical use. The purpose of this study was to improve the stride estimation method using a single inertial sensor and to verify the accuracy of stride length estimation. Stride length was estimated by integrating the horizontal acceleration at the ankle joint. To reduce the impact acceleration at ground contact, which is the primary factor causing estimation errors, we mounted an inertial sensor on the lower leg. In the present method, the following four factors contribute to the stride length estimation error: the sensitivity of the inertial sensor, consideration of the directional angle, detection of integral intervals, and estimation of the relative position vector from the inertial sensor to the ankle joint. This study presents solutions to these problems and verifies the accuracy of stride length estimation by comparing it with optical motion capture measurements. The results indicated that the sensitivity of the inertial sensor improved the accuracy of the stride length estimation. Furthermore, we found that the standard deviation of stride estimation per step was approximately 32 mm, regardless of cadence and stride length. We conclude that the stride length estimation by the acceleration integral method is applicable to the estimation of the average stride length; however, it is difficult to apply it to the evaluation of stride variation from step to step.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-material topology optimization considering material cost and displacement constraints","authors":"Shun OGAWA, Kazuo YONEKURA, Katsuyuki SUZUKI","doi":"10.1299/transjsme.23-00180","DOIUrl":"https://doi.org/10.1299/transjsme.23-00180","url":null,"abstract":"This study proposes a multi-material topology optimization approach considering the effect of material cost. The proposed method can derive the optimized configuration, the choice of materials to use, and their arrangement, which can minimize material cost while satisfying a maximum displacement constraint. An approach based on Discrete Material Optimization with material definition independence and symmetry is employed to represent the arrangement and geometry of multiple materials for an isotropic linear elastic model. This structural representation method solves the problems of local minima solutions regarding the order of material definitions and the introduction of physically difficult-to-interpret parameters, which have been issued in the past. As a result, the proposed method is highly compatible with actual product design systems. As a strength constraint, a maximum displacement constraint based on the p-norm idea is introduced. The objective function is defined as the material cost function assuming the introduced structural representation approach. Finally, a study of several numerical examples is performed. The validity and effectiveness of the proposed approach is demonstrated.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136257182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Focusing on lignin flowability of bamboo fibers extracted from machining centers a study of optimum molding conditions for self-adhesive molded bamboo fibers","authors":"Kaito TANAKA, Daigo TAUCHI, Toshiki HIROGAKI, Eiichi AOYAMA, Hiromichi NOBE","doi":"10.1299/transjsme.23-00118","DOIUrl":"https://doi.org/10.1299/transjsme.23-00118","url":null,"abstract":"In this study, we are attempting to create self-adhesive moldings made entirely from bamboo fibers extracted by a machining center in order to solve global environmental problems and the destruction of ecosystems caused by bamboo. However, the mechanical properties of the moldings are still insufficient. In the present report, we clarify the molding conditions that can improve the mechanical properties of the molded plates. First, the cause of fracture of the plates during tensile testing was investigated. As a result, it was considered that the cause was the fracture at the adhesion area or fiber withdrawal. To enhance the adhesive action, we focused on lignin, an adhesive component in bamboo, and its flow process during molding. We investigated the effects of in-mold temperature and pressure and molding time on the thermal flow of lignin. As a result, it was found that the thermal flow of lignin progressed and the mechanical properties improved as the time and pressure were increased. Therefore, we attempted to determine the molding conditions that maximize the tensile strength of the moldings by referring to a manufacturing process model for fiber-reinforced composites. Five specimens were fabricated, and a tensile strength of 32.37 MPa was achieved with a standard deviation of 0.55 MPa, which is equivalent to that of general-purpose plastics.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136257189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface to the Special Issue on TRANSLOG2022","authors":"Eiichi ONO","doi":"10.1299/transjsme.23-pre02","DOIUrl":"https://doi.org/10.1299/transjsme.23-pre02","url":null,"abstract":"","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135158300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"複合冷凍菓子の水分量の違いが感性に及ぼす影響","authors":"Keiichi WATANUKI, Masato KAWAMOTO, Kosuke OKANO, Kazuya KATSUMURA, Takumi KANO, Kyosuke KOBAYASHI, Suguru MASHIMA, Tomoya KOISHI, Mai WAJIKI, Tomohiro TAURA, Hitomi TSUCHIYA","doi":"10.1299/transjsme.23-00006","DOIUrl":"https://doi.org/10.1299/transjsme.23-00006","url":null,"abstract":"There are few studies that have conducted comprehensive verification of the physiological and psychological effects of different textures of chilled confectioneries by means of biometric measurements and subjective evaluation. The effects of confectionery texture are still unclear. Therefore, this study aimed to clarify the effects of different textures on the activity of autonomic nervous system, the brain, and muscles, and emotion by simultaneously measuring changes over time in various biological information and assessing subjective evaluation given by the tasters during consumption of different types of ice cream with monaka shell with varying water content. Participants answered a subjective evaluation questionnaire and rested for 60 s, and then performed the task. The monaka ice cream consisted of 9 blocks, each of which was eaten in 20 s. Afterwards, the participants rested for 60 s and completed a subjective evaluation questionnaire. Near-infrared spectroscopy was used to measure brain activity during eating, electromyography to measure muscle activity, and electrocardiography equipment to analyze heart rate variability. Eating monaka shell with low water content significantly activated cerebral blood flow in the right hemisphere when the first and sixth blocks were eaten. A significant trend was observed in LF/HF, which is considered an index of sympathetic nerve activity. In the mastication force test, the participants chewed significantly more strongly on ice cream with a high water content monaka shell than those with a low water content. During mastication, the participants who consumed ice cream with the low water content shell tended to use slow muscles more than those who consumed ice creams with high water content shell. The questionnaire showed that both the increase in degree of emotions such as surprise and excitement and the decrease in the degree of emotions such as sadness and depression were larger when the participants consumed ice cream with a high water content shell than those with a low water content shell. The results suggest that monaka shells with a low water content induce a more relaxed state and pleasant emotions than those with a high water content.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135753597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"孔食が存在する腐食レールに対する実応力と応力勾配を用いた疲労強度予測手法の提案","authors":"Jun MIZUTANI, Mitsuru HOSODA, Ryuichi YAMAMOTO, Yoshihiro TERASHITA","doi":"10.1299/transjsme.23-00196","DOIUrl":"https://doi.org/10.1299/transjsme.23-00196","url":null,"abstract":"Rail corrosion is one of the causes of rail breaks. The relationship between rail corrosion state and fatigue strength is still unclear. Therefore, to accurately estimate the fatigue strength of corroded rails, the prediction method for fatigue strength of corroded rails with pitting corrosion by actual stress and stress gradient was investigated. Bending fatigue tests were performed on the rails with pitting corrosion on the bottom surface. At this time, models based on the shape of the rail bottom surface were created, and actual stresses and stress gradients generated at the rail bottom surface were evaluated by the finite element method. When the fatigue test results were evaluated by the actual stress, the bending fatigue strength appeared to be higher when the fracture origin position was inside of pitting corrosion than when it was outside. This was an apparent phenomenon due to the use of actual stress, which could be explained in terms of stress gradients. Furthermore, using the relationship between the correction factor of time strength q, which expresses the relationship between the fatigue strength of new rails and the apparent fatigue strength of the corroded rails, and the stress gradient χ, it is possible to estimate the number of loading cycles that the corroded rails break in the fatigue tests.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"180 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135703726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a novel forming method to restrain wall curvature for stamping products using general purpose ultra-high tensile strength steel sheets","authors":"Hideto KATSUMA","doi":"10.1299/transjsme.23-00065","DOIUrl":"https://doi.org/10.1299/transjsme.23-00065","url":null,"abstract":"In recent years, automobile manufacturing requires both weight reduction for environmental measures and high strength for safety. For this reason, the use of ultra-high tensile strength steel sheets for frame components is increasing. For the application of ultra-high tensile strength steel sheets, it is necessary to pay attention to measures to ensure dimensional accuracy for press forming. Among them, wall curvature countermeasures are very important technologies. In this study, a novel forming method without generating wall curvature was developed using a simple hat model, and then a prototype mold was produced and confirmed. This novel forming method is a combination of the advantages for draw forming and cam bending forming. To form a shape so as not to fracture or wrinkle in a process similar to drawing, and to prevent wall curvature of a vertical wall part of a hat section in a process similar to cam bending. The forming motion consists of downward descent and multi-step sliding while holding the specimen in one forming process. In the FEM analysis before the production of the prototype mold, the conventional forming method and the novel forming method were evaluated from the viewpoint of the wall curvature, and the novel forming method gave the best results with the minimum wall curvature. The evaluation of the formed panel using the prototype mold also gave the same results as the FEM analysis. This paper shows that the developed forming method hardly generates the wall curvature even when the ultra-high tensile steel sheet is used.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135007855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Virtual sensor using model order reduction for real-time estimation of tool edge temperature","authors":"Masahiro TAKANO, Masayoshi SHINYA, Hiroyasu MIYAKAWA, Yuta YOSHIDA, Kenichi HIROSAKI","doi":"10.1299/transjsme.23-00159","DOIUrl":"https://doi.org/10.1299/transjsme.23-00159","url":null,"abstract":"Virtual sensor, which is one of the applications of the digital twin, is effective for estimating physical quantities that are difficult to measure. This paper deals with estimation of real-time tool edge temperature by virtual sensor. The tool edge temperature is estimated by inputting the temperature data of the endmill shank obtained from the pyrometer installed in the machine tool to the simulation model created in cyber space. The simulation performed in cyberspace is an unsteady heat transfer analysis, and a state space model with a reduced order of the finite element model using Krylov subspace method is adopted as the simulation model in order to allow real-time simulation. In addition, unknown heat input to the cutting edge was calculated by state feedback control using the temperature data obtained from the pyrometer and the simulation model. The tool edge temperature during cutting was estimated in real time using the developed virtual sensor with the heat transfer analysis block and the input estimation block. The estimated tool edge temperature changed significantly in response to changes such as chipping of the tool edge. The estimated temperature and the measured temperature by the thermocouple method generally matched.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136374319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diamond-like carbon film coatings on soft metal substrates","authors":"Makoto MATSUO, Takanori YAMAKI, Yuki HIRATA, Yukio TAMURA, Hiroshi YAMAMOTO, Toshio OZAWA, Gangyi PAN, Hiroki AKASAKA, Naoto OHTAKE","doi":"10.1299/transjsme.23-00171","DOIUrl":"https://doi.org/10.1299/transjsme.23-00171","url":null,"abstract":"Application of segment-structured tetrahedral amorphous carbon (ta-C) film on soft metal substrate is proposed to improve wear resistance of mechanical parts. It was generally considered that continuous structure ta-C film was effective when applied to hard materials because it could not follow deformation of substrate material and the film tended to delaminate. In contrast, by applying segment structure on ta-C film, tribological properties of ta-C film coated on soft substrate were further improved, and sliding surface exhibited excellent wear resistance even under high sliding loads. Effectiveness of the use of brass substrate in improving wear resistance was demonstrated through large-scale wear resistant test of valve-plate used in oil pump of construction machine. Segment-structured ta-C coated brass valve-plate reduced maximum wear by approximately 80 % as compared with uncoated brass plate.","PeriodicalId":485601,"journal":{"name":"Nihon kikai gakkai ronbunshu","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135358630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}