著者

根岸 秀世 雨川 洋章 間庭 和聡 小原 新吾 羽山 誠 董 大明

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.85, no.875, pp.19-00086, 2019 (Released:2019-07-25)

参考文献数

22

被引用文献数

3

---

Grease lubrication in ball bearings is one of key technologies to reduce energy consumption and enhance lifetime in design of spacecrafts as well as general industrial machineries. From a view point of grease lubrication design, it is crucial to understand grease macro flow phenomena in ball bearings taking into account non-Newtonian property of grease. In the current study, grease macro flow phenomena were investigated based on experimental and numerical works as a preliminary study. Grease dam breaking was defined as a benchmark problem and its collapsing phenomena were experimentally observed. As for the numerical work, a basic algorithm to simulate non-Newtonian grease macro flows was developed based on the explicit MPS (Moving Particle Simulation) method coupled with Bingham pseudoplastic fluid model. The observed grease dam breaking behavior was simulated by the developed numerical approach and the numerical results showed a good agreement with the corresponding experimental data.

著者

積際 徹 本元 泰穂 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.82, no.841, pp.16-00010, 2016 (Released:2016-09-25)

参考文献数

23

被引用文献数

2 3

---

The objective of this study was to develop a motion analysis system to evaluate relations between the activation of the lower limb muscles, the pedal force and the movement of the lower limb during the pedaling motion. To confirm the effectiveness of the proposed analysis system, we analyzed the pedaling motion of nine cyclists to identify their pedaling skill. In the experiments, cyclists were instructed to perform their pedaling technique at two pedaling rates (80-90 rpm and 110-120 rpm). Surface electromyography (EMG) signals was recorded from tensor of latae (TFL), rectus femoris (RF), hamstrings (HAM) and gastrocnemius (GAS), and pedal force was measured by a power meter (Pioneer Corporation). Furthermore, the lower limb motion during the pedaling was measured using a 3D motion capture system to investigate the relations among measured data as mentioned above. The experimental results show that the proposed analysis system reveals the pedaling skill of cyclists and the relations between the EMG data, the pedal force and the movement during the pedaling motion. In this paper, firstly, the activation section of the lower limb muscles during the pedaling was determined quantitatively. Secondly, Tukey-Kramer test was conducted to determine whether there are significant differences (p < 0.05) between the pedaling effectiveness of the three groups (elite group, amateur group and beginner group). Finally, the pedaling skill of the cyclists was revealed based on the analysis results of the measurement experiments.

著者

鞍谷 文保 北林 研人 小川 渉 吉田 達哉 長村 光造 小出 俊雄 文珠 義之 水田 泰次

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.17-00110, (Released:2017-07-06)

参考文献数

13

---

Cymbals are percussion instruments that vibrate and radiate sounds when hit with a stick or when used in pairs. The sound radiated from a cymbal depends on its vibration characteristics. Cymbals are made through spin forming, hammering and lathing processes. The spin forming creates the domed shape of cymbals, determining the basic vibration characteristics. The hammering and lathing make specific sound quality adjustments by changing the vibration characteristics. In this paper, we focus on how the hammering affects the cymbal's vibration characteristics. The hammering produces many shallow dents over the cymbal's surface, generating residual stresses in it. These residual stresses change the vibration characteristics. We perform finite element analysis of the hammered cymbal to obtain its vibration characteristics. In the analysis, we use thermal stress analysis to reproduce the stress distribution and then with this stress distribution we perform vibration analysis. The results show that the effects of thermal load (i.e., hammering) vary depending on the mode: an increase or decrease in the natural frequency. As a result, the peak frequencies and their peak values in the frequency response function change.

著者

Liu Chen 藤本 由紀夫 田中 義和 上杉 征 並河 隆浩

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.BMS0244, 2014 (Released:2014-08-25)

参考文献数

7

---

When human body is punched by the boxing glove, both of the body surface and the boxing glove deform in a complex shape. The purpose of this study is to develop a flexible sensor that can be used in such interface. Firstly, several mechanical phenomena, which are the cause of error signal of the sensor, are discussed. These are the influences of out-of-plane bending deformation, shear force caused by rubbing force, shear force caused by the Poisson's effect of contact material, and the transverse compressive force caused by the overhanging deformation of flexible material. Then as a sensor that can eliminate the error factors of these, a distribution type impact sensor in which sixteen sensor elements are arranged in a 4x4 matrix is developed. Punching experiments using a boxing glove are carried out by installing the sensor on the load cell, on the concrete wall and on the sandbag. From the experiment, it is found that the impact force can be measured with good accuracy by using the sensor. Despite the sensor has inadequate distribution number of sensor elements, the sensor structure includes mechanical requirements for the flexible impact sensor.

著者

永島 唯哉 池田 生馬 岩附 信行

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.85, no.873, pp.18-00439, 2019 (Released:2019-05-25)

参考文献数

13

被引用文献数

1

---

When one rides a car on a gravel road, a noise due to collision of gravels rolled up by tires makes him uncomfortable. The collisions are assumed as random impacts with respect to mass, collision time, position, velocity, angle and so on. In order to probabilistically estimate the noise, the time history of impact force in the case where a force sensor on a rigid pendulum hits a peripherally clamped thin rectangular plate is precisely measured for various impact speeds, angles and positions. The vibration response and sound pressure radiating from the plate are then estimated with the measured impact forces based on Rayleigh-Ritz method and impulse response method. It was then revealed that the time history of impact force could be represented with a certain time function for any impact speeds, angles and positions and that the component of the impact force perpendicular to the plate determined the maximum of the impact force. The time history of impact force can also be approximated as a superposition of the extreme function and Gaussian function. The estimated vibration acceleration of the plate and sound pressure agree very well the measured values. The noise generated by random impacts was estimated probabilistically. It was found that the noise strongly depends on the natural vibration modes of the plate.

著者

NGUYEN QUANG Thinh 岩村 幸治 杉村 延広 浦出 俊和 竹歳 一紀 香川 文庸 平原 嘉幸 木下 泰宏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.18-00220, (Released:2019-02-26)

参考文献数

17

被引用文献数

1

---

Much emphasis is now being given to research and development of plant factories which daily produce a large volume of high-quality vegetables under artificially controlled environments. One of the important issues to be considered for the management and the daily operations of the plant factories is to find a set of suitable customers and/or markets to which the daily produced vegetables are sold and delivered. The current wholesale markets of the vegetables are not suitable for trading the high-quality vegetables produced by the plant factories, therefore, a new market is required to sell and to buy the products made by the plant factories. A new trading market system is proposed, to sell and to buy the lettuces supplied by the plant factories, based on the stock exchange mechanisms, in this paper. An estimation method of yield rate is also proposed to generate a suitable volume of sales for the plant factories. Some case studies have been carried out to verify the effectiveness of the proposed trading market.

著者

沖野 友洋 永田 恵輔 佐藤 裕之 堀川 敬太郎 小林 秀敏

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.85, no.869, pp.18-00270, 2019 (Released:2019-01-25)

参考文献数

11

被引用文献数

2 4

---

The crash safety structure of the railway vehicles is effective as one of the safety measures against the train crews and the passengers in the event of a collision accident. However there is no standard for crash safety in Japan. In order to discuss guidelines for the crash safety design of the vehicle structure, it is important to grasp the actual situation of collision accidents in Japan. Therefore, firstly the authors performed the statistical analysis of serious level-crossing accidents for the past 30 years. Secondly, we carried out finite element analyses of a level crossing accident with a dump-truck under various conditions (collision position, collision angle, collision speed and mass of the load on the dump-truck) based on the result of the statistical analysis. We also evaluated their results in terms of the contact force, the deformation energy of the rail vehicle, the deformation amount of the cabin, the mean deceleration of passenger’s area (conformable to European standard), the maximum deceleration of the passenger’s area and the secondary impact velocity of the passenger (American standard). The degree of correlation among these results was discussed. The analyses showed that the horizontal collision position of the dump-truck and the collision speed had a comparatively large effect on the safety of passengers, and further that the mass of the load on the dump-truck also affected it when the secondary impact velocity was used as an evaluation index.

著者

岩部 洋育 菊池 恭平 白井 健司

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.15-00289, (Released:2015-11-12)

参考文献数

6

被引用文献数

1 4

---

This paper deals with the geometrical analysis of the surface roughness of a radius end milled workpiece with an inclined surface using the contouring and scanning cutter path methods. In the case of contouring, first it was classified into three types of cutting edges for generation of inclined surface. Secondly, three equations of the theoretical roughness of the machined surface were lead based on the geometrical analysis for each type. The calculation values of surface roughness almost coincide with the experimental values, therefore the validity of the analytical method is cleared. In the case of scanning, first the envelope surface of the bottom and corner edges was defined as the lower half surface of the torus. Secondly, the calculation and estimating method of the envelope curve which was obtained by the outside line of the projected torus surface is shown. The estimated values of surface roughness almost coincide with the experimental values, therefore the validity of the analytical and estimating method are cleared too. Finally, the selection of the scanning method is more effective in order to achieve highly accurate machining.

著者

黒島 亮 大高 武士 門 久義

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.FE0318, 2014 (Released:2014-11-25)

参考文献数

21

---

Recently, the micro-bubble technologies are applied in a wide field, and grow to the field close to the human lives. Though many methods of micro-bubble generation have been proposed, pressure loss of a venturi tube is less than among others. The studies on micro-bubble generation with venturi tube have ever seen, but the generation mechanism of a micro-bubble is not fully evident. The purpose of this paper is to make the micro-bubble generation mechanism experimentally clear. In conclusion, by inspecting the images of high-speed camera, the water jet occurs on the trailing edge of a bubble when its leading edge arrives at the throat inlet and divides it into two parts in the throat section. Then, passing through the diffuser, outer shapes of the two parts become unstable and break down into micro-bubbles. It is clear that the mechanical conditions of this occurrence are based on the accelerations at a nozzle and a diffuser. Then, the generated bubble size is distributed around a peak of about 200µm.

著者

横山 綾亮 小村 啓 坪井 諭之 大岡 昌博

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.18-00283, (Released:2018-10-30)

参考文献数

13

---

Hardness representation in VR is one of the important problems to create virtual touch feeling as if the feeling is caused by real touch. In this study, we are attempting to improve the hardness representation method by combining the pseudo-haptics and tactile stimuli, which was presented in our previous research. In the current study, we investigated the ability of both of these methods to express tactile hardness stimulation: in Experiment A hardness was generated solely by visual stimulation using CG; and in Experiment B hardness was generated solely by the dot-matrix display. Based on the results of Experiments A and B, in Experiment C we conducted psychophysical experiments on the ability to express tactile hardness by combining the effects of pseudo-haptics and the tactile stimuli. In Experiment C, we were able to express six levels of distinguishable hardness, while only four and two levels were observed in Experiments A and B, respectively. In addition, the relationship between hardness evaluation and the six levels shows high linearity with R2 = 0.98.

著者

木原 玄悟 吉本 勇太 堀 琢磨 高木 周 杵淵 郁也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.865, pp.18-00193, 2018 (Released:2018-09-25)

参考文献数

33

---

We constructed a coarse-grained (CG) water model based on non-Markovian dissipative particle dynamics (NMDPD) taking into account memory effects. The NMDPD equation of motion was derived from a generalized Langevin equation formulated via the Mori–Zwanzig (MZ) projection operator. We extracted a CG pair potential and memory kernels between clusters comprising 10 water molecules by means of molecular dynamics (MD) simulations. We found that the MZ-guided CG potential followed by an iterative Boltzmann inversion correction resulted in an accurate representation of both a radial distribution function and pressure. Furthermore, in contrast to Markovian DPD, the NMDPD model exploiting MZ-guided memory kernels could reproduce short-time dynamics originating from molecular collisions, which was characterized by decaying nature of a velocity autocorrelation function (VACF). The NMDPD model was also able to reasonably represent the viscosity of the MD system compared to the conventional DPD, where interaction parameters were phenomenologically tuned such that a few macroscopic properties were reproduced, leading to a significant underestimation of a viscosity or Schmidt number. Finally, the differences of the viscosity and long-time behavior of the VACF between MD and NMDPD systems implied the necessity of a more appropriate description for a one-to-one correspondence between a CG particle and a water cluster.

著者

宮﨑 達二郎 井上 卓真 野田 尚昭 佐野 義一

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

巻号頁・発行日

vol.84, no.864, pp.18-00013-18-00013, 2018

被引用文献数

2

---

<p>In this paper, convenient analysis methods are proposed for analyzing the singular index and the intensity of singular stress field (ISSF) at the vertex on the interface in the three dimensional (3D) bonded body. The analysis methods focus on FEM stresses at and around the vertex. The singular index is determined from the FEM stress ratio at the vertex obtained by performing FEM analyses for the finely and coarsely meshed models. Then, the ISSF is determined from the average FEM stresses around the vertex obtained for the reference and unknown models by applying the similar mesh pattern. The validity of the present methods is examined by comparing the results of 3D bonded models with/without fixed free surfaces. It is found that the obtained singular index has the same accuracy as the FEM eigenvalue analysis. The asymptotic solutions with the singular index and ISSF obtained by the present method correspond to FEM stress distributions. Since the ISSF obtained by the body force method (BFM) is used as the reference solution, the present method for ISSF has the same accuracy as BFM. Moreover, the critical ISSF values are calculated from the experimental results of the butt joints under various adhesive thicknesses. The critical ISSF at the side of 3D butt joint is in good agreement with the critical ISSF of 2D butt joint model. It is shown that the critical ISSF at the vertex of 3D joint is constant as well as the critical 2D ISSF independent of the adhesive thickness.</p>

著者

宮﨑 達二郎 井上 卓真 野田 尚昭 佐野 義一

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

巻号頁・発行日

2018

被引用文献数

2

---

<p>In this paper, convenient analysis methods are proposed for analyzing the singular index and the intensity of singular stress field (ISSF) at the vertex on the interface in the three dimensional (3D) bonded body. The analysis methods focus on FEM stresses at and around the vertex. The singular index is determined from the FEM stress ratio at the vertex obtained by performing FEM analyses for the finely and coarsely meshed models. Then, the ISSF is determined from the average FEM stresses around the vertex obtained for the reference and unknown models by applying the similar mesh pattern. The validity of the present methods is examined by comparing the results of 3D bonded models with/without fixed free surfaces. It is found that the obtained singular index has the same accuracy as the FEM eigenvalue analysis. The asymptotic solutions with the singular index and ISSF obtained by the present method correspond to FEM stress distributions. Since the ISSF obtained by the body force method (BFM) is used as the reference solution, the present method for ISSF has the same accuracy as BFM. Moreover, the critical ISSF values are calculated from the experimental results of the butt joints under various adhesive thicknesses. The critical ISSF at the side of 3D butt joint is in good agreement with the critical ISSF of 2D butt joint model. It is shown that the critical ISSF at the vertex of 3D joint is constant as well as the critical 2D ISSF independent of the adhesive thickness.</p>

著者

藤井 正浩 國冨 裕太 石田 浩規

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.820, pp.TRANS0339, 2014 (Released:2014-12-25)

参考文献数

8

---

In order to clarify the effect of surface profile on friction characteristics of viscoelastic material used for oil seal, sliding test was conducted under oil lubrication with the NBR (Nitrile Butadiene Rubber) specimen in combination with steel specimen. The sliding surface profiles with different feature in the steel specimens were introduced by polish process and blast process. The NBR specimens with different surface feature were also employed. Under a low load condition, steel specimens with plateau surface showed the lower friction coefficient. The reduction of contact area and pocket effect could lead to the lower friction coefficient. Similar effect was provided by the NBR specimens with rough surface or dimples. Friction behavior under a low load condition was influenced by adhesion force. The adhesion force decreased with increasing surface roughness, that is with decreasing contact area. Therefore, the friction coefficient decreased with increasing surface roughness in NBR specimen. The friction coefficient of the NBR specimen with dimples which had small asperity and large concave portion was remarkably small under a low load condition. On the other hand, under a high load condition, where the deformation of NBR specimen was rather large, the effect of surface profile on friction coefficient was small.

著者

橋本 博文 今井 栄一 矢野 創 渡辺 英幸 横堀 伸一 山岸 明彦

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

巻号頁・発行日

vol.82, no.835, pp.15-00538-15-00538, 2016

被引用文献数

1

---

The mechanical thermometer using a bimetallic strip coil was developed for the Tanpopo mission. The Tanpopo mission is a multi-year passive exposure experiment for astrobiology exposure and micrometeoroid capture onboard the Exposed Experiment Handrail Attachment Mechanism (ExHAM) at the Japanese Experiment Module 'Kibo' (JEM) Exposed Facility (EF) on the International Space Station (ISS). The Tanpopo mission apparatuses were launched by the SpaceX-6 Dragon CRS-6 on April 14 2015, from the Cape Canaveral Air Force Station in the U.S.A. Since its microbial exposure experiment requires recording the maximum temperature that the Tanpopo exposure panel experiences, we have developed a mechanical thermometer with no electric power supplied from the ExHAM. At a given time and orbital position of the ISS, the thermometer indicator was video-imaged by the extravehicular video camera attached to the Kibo-EF and controlled from the ground. With these images analyzed, we were able to derive the maximum temperature of the Tanpopo exposure panels on the space pointing face of the ExHAM as 23.9±5 °C. Now this passive and mechanical thermometer is available to other space missions with no electric supplies required and thus highly expands the possibility of new extravehicular experiments and explorations for both human and robotic missions.

著者

佐藤 航 磯島 宣之

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.844, pp.16-00207, 2016 (Released:2016-12-25)

参考文献数

21

被引用文献数

2

---

To achieve precise temperature control, Peltier devices, which are also called thermoelectric coolers, are widely used. However, simulating the unsteady temperature history caused by the Peltier devices is difficult because the amounts of heat absorption and generation are affected by their temperature. The temperature dependence reportedly can be calculated using the quadratic equation of temperature and the typical temperature characteristic coefficients. However, as the temperature dependence varied among the manufacturers, the temperature characteristic coefficients had to be modified for each of the devices. We developed a technique to determine the temperature characteristic coefficients of the Peltier device automatically by using data assimilation. We integrated the particle filter, one of the data assimilation algorithms, into the thermal network method and enabled estimating the suitable temperature characteristic coefficients. To demonstrate the estimation, we evaluated a Peltier device. The constant current 1.0 A and its inverse current were applied to the sample device repeatedly, and the temperature of the control object fluctuated repeatedly between 40 °C and 90 °C was measured. The temperature change was simulated using the thermal network method with the typical temperature characteristic coefficients and the history was compared with the measurement results. The root mean square error of temperature between the measurement and the calculation results was 3.20 K. Then, we estimated the applicable value of the temperature characteristic coefficients by applying the particle filter combined with the thermal network model. When the estimated coefficients were applied to the thermal network model, the root mean square error of temperature decreased to 1.39 K.

著者

森脇 一郎 上田 昭夫 射場 大輔

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.863, pp.18-00033, 2018 (Released:2018-07-25)

参考文献数

9

被引用文献数

1

---

The present paper describes edge contact analyses for power transmission gears using tooth-flank-film elements, which have been proposed for finite element analyses of tooth stresses. For edge contact analyses, the tooth-flank-film elements are placed not only on usable flanks but also over tooth edges. Finer elements on edge neighboring areas and on the parts of usable tooth flanks where tend to contact with mating edges enable the edge contact to be analyzed. Comparisons of calculated distributions of tooth contact stress with observed tooth flanks after a running test showed the validity of the proposed method for edge contact analyses.

著者

田辺 郁男 水谷 淳之介 高橋 智 熊井 達也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.863, pp.17-00516, 2018 (Released:2018-07-25)

参考文献数

12

被引用文献数

1

---

Recently the design of experiments is used to decide optimum processing conditions. However when the control factor interaction between the several control factors becomes large, the calculated accuracy using the design of experiments becomes very bad. Then everybody should check the results regarding the best and the worst conditions in the experiments. If differences between the calculated vale and the experimental value for the best and the worst conditions become large, the results using the design of experiments are never used. Therefore, in the previous research, we have developed the tool for easily finding the control factor interaction in the design of experiments. This control factor interaction between the several control factors action is large fault, an obstacle for innovation and disliked by everybody. However when the reaction between the several control factors becomes large effect which is surpassed the estimate, the control factor interaction becomes the synergistic effect which is liked by everybody, the synergistic effect finally brings large profit, excellent license and innovation. Therefore in this research, the tool for easily finding the synergistic effects between the control factors was developed and evaluated using the program in the previous research. The program was the tool for finding the control factor interaction in the design of experiments, it was improved for the easily finding the synergistic effects by using the new algorithm, and was evaluated by the several mathematical models and the experiment. It is concluded from the result that (1) the new program can clear the synergistic effects between the control factors, (2) the program also can clear the complex multiplier effects and (3) the program can clear the synergistic effects with innovative profit in the actual example.

著者

荒井 皓一郎 岡田 裕 遊佐 泰紀

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.863, pp.18-00115, 2018 (Released:2018-07-25)

参考文献数

25

被引用文献数

3

---

In this paper, a new formulation of three-dimensional J-integral for the evaluation of elastic-plastic fracture problem is presented. It is known that the J-integral represents the energy release rate per unit crack extension. The J-integral is a path-independent integral and can be computed on arbitrary integral path or domain. This property requires the assumption of proportional loading when an elastic-plastic material is considered. Because of this assumption, J-integral loses path-independent property under a non-proportional loading condition. We present a new formulation of three-dimensional J-integral representing the energy dissipation inside a small but finite domain in the vicinity of crack front. The dissipated energy includes the energy released by crack extension and the deformation energy that dissipates in the process zone. This formulation is the extension of the three-dimensional J-integral using equivalent domain integral method and derived without any assumptions on the deformation history. Therefore, it is possible to evaluate the J-integral for problems subject to any load histories. Finally, the problems of hyperelastic and large deformation cyclic elastic-plastic analysis using finite element method are presented. They show that the proposed method can be applied to non-proportional loading problem.

著者

牟禮 良晃 河野 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

vol.84, no.863, pp.17-00589, 2018 (Released:2018-07-25)

参考文献数

16

被引用文献数

1

---

Three-dimensional (3D) numerical simulation of incompressible, magnetohydrodynamic (MHD) flows under alternating-current (AC) magnetic fields are carried out, which takes into account the coupling with the electromagnetic fields in the solid and gas regions. A numerical scheme is constructed by combining the Galerkin finite element method and the edge-element based finite element method, which are applied to the discretizations of the Navier–Stokes equations and the electromagnetic field equations, respectively. The solution algorithm for fluid flow is based on an explicit fractional step approach and the simultaneous relaxation of velocity and pressure to satisfy the continuity equation. The electromagnetic field equations are formulated with the use of the magnetic vector potential which is defined on the edge elements. In the proposed numerical scheme, the advection term in the induction equation is not neglected, because the scheme needs to deal with the condition where the advection term is the same order with the diffusion term in that equation. The validity of the numerical scheme is verified through the analysis of the electromagnetic field under a direct-current magnetic field, and numerical simulations of the MHD flows under spatially uniform AC magnetic fields are carried out. It is confirmed that the spatio-temporal mean Lorentz force in the conducting fluid becomes weaker with the increase in the dimensionless frequency due to the skin effect. It is also shown that the flow pattern in a hexahedral closed domain is largely changed when the frequency is getting higher, which is associated with the change in the Lorentz force profile.