著者

藤井 文夫 Kuo Mo HSIAO 小林 卓哉 井上 吉弘 新田 高洋

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 (ISSN:21879761)

巻号頁・発行日

vol.82, no.836, pp.15-00623, 2016 (Released:2016-04-25)

参考文献数

9

被引用文献数

1

---

The popular sports entertainment, billiards, is rich in mechanical issues such as 3D finite rotation, collision, contact and friction, evoking a research interest in rigid-body dynamics, nonlinear CAE and computational mechanics. However, the 3D nonlinear behavior of a rigid ball has so far hardly received the attention of scholars to exercise the mechanical modeling skill. The represent study focuses, therefore, on 3D nonlinear billiard dynamics and attempts to precisely predict the ball behavior in finite rotational motion with collision, contact and slip friction. In dependence upon ball situations, 4 different models are proposed. They are namely, rotation model, strike model, collision model and reflection mode. The rotation model is an elementary model and describes the 3D ball motion after a cue strike and subject to table friction only. The strike model is useful to study the effects of cue striking. For simplicity, the strike points are limited to the ball center, 12, 3, 6 and 9 o'clock' in the ball projection. The collision model ignores the ball-to-ball friction and the law of conservation of momentum holds to predict the velocities of two balls after collision. The reflection model simulates the ball-to-cushion contact in bank shots. Incidence angle, translational and rotational velocities, cushion elasticity and frictional properties may be variable in a parameter study. In all these 4 models, the ball is assumed to be in contact to the table surface. Masse or jump shots are excluded in modeling. The equations of ball motion are time-integrated by forward Euler method. The models are verified and validated in numerical examples including optimization and parameter studies. All computed results well agree with the hustler’s experiences in game practice. The present research work will contribute to develop a skill-up program of professional hustlers.

著者

松下 和磨 森本 雄矢 竹内 昌治

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.86, no.890, pp.20-00180, 2020 (Released:2020-10-25)

参考文献数

13

被引用文献数

1 3

---

Biohybrid robots composed of synthetic skeletons and living components have recently gained interests as a solution to engineering biological dynamic systems. Among the living components, muscle tissues are used as actuators for biohybrid robots, resulting in vitro reproduction of various movements. Especially, swimming robots containing living muscle tissues or cardiomyocytes have been proposed as representative examples of biohybrid robots. However, these robots have limitations on reproducibility and controllability due to individual differences between each explanted living muscle tissues and the self-contraction of cardiomyocytes, respectively. To solve the issue, a swimming robot with cultured skeletal muscle tissue is required since it allows to control the shape and contraction of the cultured tissue. In this paper, we propose the construction method of a swimming robot with cultured skeletal muscle tissue. Our method can prevent spontaneous shrinkage before transferring the tissue from an appropriate culture substrate for tissue formation to the swimming robot. Using the method, we succeeded in the preparation of a swimming robot with three different robot skeleton and skeletal muscle tissues cultured under the same condition, regardless of the spontaneous shrinkage during culture. As a result, we obtained the relationship between shapes of robot skeletons and propulsion of the robot and confirmed that the robot can move forward by shaking a tail fin. We believe that the method for integrating skeletal muscle tissues with the synthetic skeleton will be useful for the easy preparation of biohybrid robots and devices.

著者

田中 泰爾 大石 義彦 朴 炫珍 田坂 裕司 村井 祐一 川北 千春

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.88, no.907, pp.21-00297, 2022 (Released:2022-03-25)

参考文献数

24

---

Drag reduction by bubble injection in turbulent boundary layers was investigated using a 36-m-long flat-bottom model ship. The model ship was towed at 8.0 m/s, resulting in a downstream-distance-based Reynolds number as high as 2.9 × 108. The total resistance exerting on the model ship was reduced, and the resistance reduction increased with the air flow rate for the bubble injection. The local wall shear stress on the bottom plate was measured at multiple locations to clarify the streamwise transition of the drag reduction. The local drag reduction observed at the upstream measurement locations was increased with the air flow rate. The higher gas flow rate, moreover, produced the longer streamwise persistence of the drag-reduction effect. These multiple factors improved the efficiency of the total resistance reduction against the power consumption for the bubble injection. We provide the estimation of total frictional drag reduction for the full-scale ships using the equation of the local friction coefficient obtained experimentally. The results of the model ship experiment and the full-scale estimation consistently indicated that the downstream persistence of the local drag-reduction effect strongly affect the total drag reduction of such the long hulls.

著者

岡田 昌史 黒須 寛明

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.88, no.906, pp.21-00317, 2022 (Released:2022-02-25)

参考文献数

12

被引用文献数

1

---

Because mechanical parts will be broken by high acceleration caused by impact of collision, a shock reduction mechanism takes an important role for mechanism design. Springs and dampers have been often used for a shock absorber, however, because of their mass, the impact is transmitted to the body. Momentum exchange impact damper (MEID) and mechanical singularity will be effective mechanism design. The former transfers momentum from body to damper-mass to reduce the body velocity. The latter avoids impact transmission. This paper proposes an impact mitigation mechanism inspired by break-fall in Judo. The mechanism exchanges momentum without additional sensor nor actuator, and avoids impact transmission by singular configuration. It is shown that the proposed mechanism has 1-DOF by Kutzbach-Gruebler’s equation using a planer model and two singular configurations by singularity analysis. Dynamics simulation confirms the concept of the proposed mechanism (Momentum exchange). And a prototype is designed and motion captured by a high speed camera to evaluate the momentum exchange.

著者

松永 信智 坂本 将一 田中 友樹 岡島 寛

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.858, pp.17-00349, 2018 (Released:2018-02-25)

参考文献数

19

被引用文献数

1 1

---

Recently, electrical welfare vehicles driven by two motors employing free casters are widely used by patients and elders. However, as the user is not able to drive the vehicle well on the uneven rough roads, it is necessary to apply a new mechanism to drive on the rough road in order to expand driving area. The skid steer vehicle (SSV) has been used because of its high traveling ability on the rough road. However, the SSV has disadvantage that is, the driving assistance is required because its steering is highly affected by the road condition. The aim of this study is to design a driving assistance system of SSV for patients and elders by using Model Error Compensator (MEC) that suppresses the modeling error. The proposed controller consists of MEC, Extended Kalman Filter (EKF) that reduces sensor noise and system noise, and estimator of on-line cornering power of SSV. The effectiveness of the proposed system using on-line cornering power estimator is confirmed by the outdoor driving experiments. And the improvement of the driving assistance is evaluated by the correlation of the joystick manipulation comparing the paved and the dirt roads.

著者

田島 利基 李 沛譲 朱 赤

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.20-00372, (Released:2021-04-09)

参考文献数

15

---

In recent years, electric powered wheelchairs have become indispensable in long-term care. Up so far, many electrically powered wheelchairs have been developed to reduce the burden of caregivers, in which omnidirectional electrically powered wheelchairs attracted researchers’ attentions because these types of EPWs can be used without stress in narrow and/or crowded spaces. In this research, we have developed an omnidirectional wheelchair typed mobile assistive robot with power assistance. In addition, traditional electric powered wheelchairs use a joystick or a force sensor as the operation interface. Joysticks cannot be used by the elderly or disabled, and force sensors are too expensive to be used for wheelchairs. In this study, we have developed a new type of Human Machine Interface (HMI) using a mechanism that can detect force at low cost by using linear potentiometers and compression coil springs instead of a force sensor. The accuracy of the developed HMI is verified, and its effectiveness is confirmed in practical use. Further, we conducted power assisted experiments in forward/backward and lateral directions and turn on the spot using an admittance control with the developed HMI attached to our omnidirectional wheelchair robot. From the experimental results, the developed HMI control accurately measures the forces applied on the wheelchair by the user. Finally, a power-assisted experiment was conducted in the straight direction on a 5-degree slope. These experiments proved that our HMI-based power assist system is effective for omnidirectional wheelchairs.

著者

乾 公昭 森川 昌英 橋本 雅文 所谷 康平 高橋 和彦

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.83, no.854, pp.17-00061, 2017 (Released:2017-10-25)

参考文献数

21

被引用文献数

1

---

This paper presents a method of correcting distortion in 3D laser-scan data from in-vehicle multilayer laser scanner. A robot identifies its own 3D pose (position and attitude) in a laser-scan period using the normal-distributions transform (NDT) scan-matching method. Based on the pose information, the robot's pose in a period shorter than scan period under the assumption that the robot moves at almost constant linear and turning velocities. The estimated pose of the robot is applied to map laserscan data onto a world coordinate frame. Subsequently, the robot again identifies its own 3D pose from the mapped scan data using NDT scan matching. This iterative process enables the robot to correct the distortion of laser-scan date and accurately map the laser-scan data onto the world coordinate frame. Two methods for correcting the laser-scan data are presented: linear-interpolation based and Kalman-filter based methods. The former applies the extrapolation and interpolation to estimate the vehicle pose, while the latter applies the prediction, estimation, and smoothing. Experimental results of mapping a signal light in a road environment show the performance of the proposed two methods.

著者

高田 宗一朗

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.87, no.893, pp.19-00271, 2021 (Released:2021-01-25)

参考文献数

15

被引用文献数

1

---

This paper discusses the new identification method of a linear single-degree-of-freedom system using Gaussian random vibration response. The propose method is based on the method of Maximum Likelihood Estimation (MLE). The likelihood function of the proposed method is composed from the analytical solution of Fokker-Planck equation. The estimation formulas of unknown parameter are obtained by maximization of the original likelihood function. The obtained estimators represent the population variance estimation problem of multivariate Gaussian model. Furthermore, the numerical identifications are conducted using the random vibration response by calculation result of the 4th Runge-Kutta method. In the result, the estimation performance of the propose method is confirmed in terms of the dependency of sample number and dependency of the damping coefficient. Especially, the proposed method is implied the application to identification problem of the large damping system. Quantification of the large damping characteristic is the important problem, because it is the difficult problem in the conventional identification method. Moreover, the benchmark tests are conducted with Half-Power Method (HPM) based on the spectral analysis and Auto-Regressive Method (ARM) based on the time series analysis, respectively. The results of the benchmark test are shown in the accuracy of the propose method is higher than its of HPM and ARM, respectively. Finally, the expansion to the recursive estimation algorithm is conducted using MLE estimator of recurrence form. In addition, the operation of the recursive algorithm is confirmed.

著者

橋本 直樹 薗部 正和 加藤 尚志 村上 徹

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.19-00095, (Released:2019-09-05)

参考文献数

11

---

JR east is developing a new ground coil to handle future speed increments in Shinkansen trains, as it is necessary to expand response distance of ground coils to cope with higher speeds. In addition, when lowering the mounting position of ground coils (as a measure against damage from falling ice), a need arises to adjust (expand) response distance. Therefore, in this research, we investigated measures to expand response distance of ground coils from the view point of feasibility, while maintaining compatibility with the current method. This research proved that an external power supply is effective for expanding response distance, so we have built a prototype ground coil with a built-in battery as a means of external power supply. The voltage detection control circuit supplies battery power only when electromagnetic waves are detected. The circuit configuration also uses a voltage induced by electromagnetic waves. This allows the battery to be used for more than 10 years. The high-speed rotation test confirmed that the prototype ground coil is capable of coping with 400 km/h even 300 mm from the ground coil and the on-board antenna. A falling-weight test confirmed that a new sturdier mounting base was capable of withstanding a load equivalent of 400 km/h. Since it was conformed that the prototype’s sufficient performance, we now plan to conduct a field test for practical use.

著者

水野 徳人 山川 勝史

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.83, no.845, pp.16-00049-16-00049, 2017 (Released:2017-01-25)

参考文献数

17

被引用文献数

1

---

Dolphin kick swimming is an underwater undulatory motion which is similar to the way dolphin and other cetaceans swim, and it's utilized after dives and turns in competitive swimming. Since in the international rules underwater limit is 15m which is 30% of 50m pool, this swimming technique has large effect on swimming records. Thus, it is essential to know and control fluid dynamics of dolphin kick swimming. In this paper, flow around human in dolphin kick swimming is simulated and the results are evaluated. To implement the simulation, dolphin kick movement is reproduced on computer by 3D model of male swimmer and changes of 5 joint angles are captured from the video footage, and the flow around swimmer model is computed by means of a moving grid finite volume method. This computational approach completely fulfills geometric conservation laws, so that moving boundary problems become resolvable. Also, a moving computational domain method actualizes unrestricted move of swimmer model. Furthermore, coupling of these methods and kinematics allows swimmer model to dynamically accelerate and decelerate by the forces applied to itself. The result shows that most of the thrust is produced in down-kick, and the ring vortex is generated in the wake, which appears in practical dolphin kick swimming. And the speed of swimmer model agrees with the speed of swimmer in the video footage.

著者

中嶋 大智 相田 健一郎 秋山 裕喜 瀧上 唯夫 富岡 隆弘 西山 幸夫 田中 隆之 宮本 岳史 今岡 憲彦

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.83, no.854, pp.17-00078, 2017 (Released:2017-10-25)

参考文献数

21

被引用文献数

3

---

It is pointed out that the yaw dampers, which are often installed in between carbody and bogie frame of a high-speed railway vehicle, have such unfavorable points that the damping force is generated not only in the yawing direction but also in other direction. As a result the damping force is generated also to the longitudinal or pitching vibration of a bogie, and the excitation force acts in the longitudinal direction of the carbody resulting in the increase of the carbody vibration of the longitudinal or vertical direction. In this research, to enable the reduction of the excitation of the carbody vibration while maintaining the original function of yaw dampers to prevent bogie hunting motion, a new mounting structure of yaw dampers on railway vehicles has been developed. The new mounting structure enables to reduce the excitation force transmitted from a bogie frame to a carbody through yaw dampers. In this paper, the effect of yaw dampers on the carbody vertical vibration is firstly shown based on the results of an excitation test of a full-scale vehicle, then the outline of the new mounting structure for yaw dampers and the design and manufacture of the prototype device are presented. The vehicle dynamics model based on multi body dynamics was constructed and the suppression effect of the yaw damper force generated to movement in the direction other than the yawing direction of a bogie was verified by the numerical simulation. Moreover, the prototype device was installed on a full-scale test vehicle and a bogie hunting motion test was carried out to verify the running stability.

著者

藤川 正毅 石川 清貴 真壁 朝敏 田中 真人 笹川 崇 表 竜二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.15-00454, (Released:2016-01-15)

参考文献数

13

被引用文献数

6 5

---

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

著者

太田 崇文 岡田 耕治 齊藤 梓 吉田 一也 村澤 剛 川上 勝 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.83, no.850, pp.16-00567, 2017 (Released:2017-06-25)

参考文献数

15

被引用文献数

2 4

---

In this work, we present a comparison of the mechanical properties of 3D printed structures with respect to the printing orientation for 3D gel printer "SWIM-ER" and FDM (Fused Deposition Modeling) 3D printer with a result that the fracture surface of the 3D modeled object of the gel does not break along the stacked line, and the maximum stress at that time is the breaking strength. Also, the fracture surface of the 3D model of the ABS resin has broken along the stacked line other than 0 degrees, and the maximum stress at that time is the peel strength. The yield point can be observed at the 0 degree specimen, the maximum stress at that time is tensile strength. Moreover, while comparing both materials, we observed that the dependency in the stacking direction is weak in the 3D model of the gel, strong in the 3D modeled material of the ABS resin, and the dependence on the stacking direction is strongly influenced by the way of bonding the materials in stacking.

著者

廣瀬 徳晃 津坂 祐司 清水 毅 山内 智裕 白石 孝 谷中 壯弘

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.15-00087, 2015 (Released:2015-06-25)

参考文献数

17

被引用文献数

2 5

---

The various kinds of the electric personal mobility, which is one or two-seater, are being developed all over the world. These mobilities are applied into the substantiative experiment held in the several cities in order to investigate the effectiveness and popularity. The main specification of the personal mobility is the small footprint to reduce the parking space and alleviate traffic jam. However, the small footprint causes the deterioration of the posture stabilization. The authors are developing the personal mobility, which has a lean actuator to tilt the upper body for keeping the posture stabilization not only during turning motion but also on the uneven road surface. In this paper, the motion model considering yaw motion around roll axis is derived. In addition, the posture control method based on the motion model is proposed to realize the desired roll angle, which ensures the required range of the zero moment point. The effectiveness of the proposed approach is verified by the experiments using a prototype.

著者

濱野 拓人 小野里 雅彦 田中 文基

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.859, pp.17-00480, 2018 (Released:2018-03-25)

参考文献数

19

---

House-collapsing simulation using a physics engine is an effective method for acquiring structural data regarding collapsed houses with the aim of understanding the properties of destroyed or disordered structures for designing and operating rescue-robots. However, the simulation needs a lot of time since a house model consists of a large number of rigid bodies and joints. In order to find an appropriate configuration of computer hardware and software for accelerating house-collapsing simulations, this study evaluates the performances of four major physics engines, namely Open Dynamics Engine, Bullet Physics Library, PhysX 2.8.1 and PhysX 3.4, by comparing the processing time about two sample structures including only rigid bodies or rigid bodies constrained by joints. Results of the experiments show that the use of multi-core CPU and GPU, especially high-speed GPU, on PhysX 3.4 has the best performance since it can process a large number of rigid bodies and joints in parallel. Based on the results, an existing simulation system has been improved and the collapsing process of one-house, which consists of about 7,500 rigid bodies and 15,000 joints, can be simulated in real-time using multi-core CPU and GPU. Moreover, this study estimates the size of GPU memory which is required for simulating the large-scale field on PhysX 3.4 to enlarge the scale of simulation. Consequently, the collapsing process of thirty-houses which includes interactions between collapsed houses can be simulated.

著者

高田 宗一朗

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.86, no.881, pp.19-00172, 2020 (Released:2020-01-25)

参考文献数

13

被引用文献数

1

---

The author proposed the identification method of symmetric nonlinear system based on the Auto-Regressive analysis and the method of averaging in a previous paper. However, there is a problem that conventional methods including the one in the previous paper cannot address the identification of asymmetric vibrating systems. In this paper, the system identification in asymmetric nonlinear system is investigated. At first, formulation of identification problem is conducted. The identification problem is described using the method of Krilov-Bogoliubov-Metropolsky is considered the two-order approximation. The description contains the amplitude dependency however coefficient of the sign cannot discriminate. Therefore, this paper proposes a new system identification method to solve these problems by identifying appropriate sign of nonlinear parameters based on movement of center-of-vibration. Identification experiment is conducted using numerical investigation, Runge-Kutta method. A nonlinear coefficient is considered in two cases: positive number and negative number. In both cases, the proposed method gives good estimated results which show good agreement with the true values. Moreover, identification experiment is conducted using the cantilever system subjected to the magnetic force. The proposed method gives estimated results which shows good agreement with the true experiment values.

著者

佐藤 俊之 永瀬 純也 嵯峨 宣彦 齋藤 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.83, no.853, pp.17-00142, 2017 (Released:2017-09-25)

参考文献数

24

---

This paper proposes a two-degree-of-freedom control systems design using a preview feedforward controller called zero phase error tracking controller (ZPETC) to improvethe tracking performanceof the disturbance observer-basedPredictive Functional Control (PFC) systems. To this end, we derive a pulse transfer function representation of the PFC controller, which is used for the design of ZPETC, and show some properties of the PFC controller. Then a disturbance observer-based PFC system combined with ZPETC is designed. Several experiments using a single axis table drive system are conducted to validate the effectiveness of the proposed control method. The experimental results show that the tracking error is dramatically reduced compared to the previously-developeddisturbance observer-based PFC.

著者

藤川 正毅 田中 真人 井元 佑介 三目 直登 浦本 武雄 山中 脩也

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.86, no.881, pp.19-00256, 2020 (Released:2020-01-25)

参考文献数

20

被引用文献数

1

---

A numerical calculation scheme for stress and its consistent tangent moduli with hyper-dual numbers(HDN) for Ogden-type hyperelastic material model was proposed. The main advantage of this scheme is that once the framework is coded, any Ogden-type hyperelastic material model can be implemented by only re-coding the strain energy density function. In this scheme, the new differentiation method for eigenvalue and eigenvector of the symmetric matrices with HDN were proposed. The proposed method can calculate the eigenvalue and eigenvector in non-real part analytically by using the eigenvalue and eigenvector in real part, in case that all eigenvalues in real part are not multiple root. We implemented the Neo-Hookean model and the Ogden model with the proposed scheme, to confirm the effectiveness and robustness of this method, and applied it to some examples. As the results, it was confirmed that the numerical results of the proposed method showed good agreement with analytical ones.

著者

原 進 鈴木 健太 山田 陽滋

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.83, no.855, pp.17-00208, 2017 (Released:2017-11-25)

参考文献数

17

---

Recently, proceeding of the aging society has encouraged research and development of power assist systems. The authors' research group studies on the assist system control using an assist cart as a rollator. The merit of the proposed system is the aging people walk by themselves using the cart as the assisting tool and it helps anti-aging. Most serious problems of the proposed system are the avoidance of fallings and collisions without losing operability. To solve the problem, this paper proposes the remote control system taking operators' safety and operability into account. The remote control has a possibility of the establishment of the cost-effective multiple target control systems by reducing the requirement for each control target system. However, because of the limitation of communication data capabilities, the controller cannot grasp the state of the controlled object completely. To grasp the state and keep the safety, the authors apply an evaluator in the remote control system. It detects the effect of the uncertainty and keeps the controlled object safe. In addition, as an interface for the users to avoid the collisions, this paper applies the stiffness control. Introducing the virtual spring into the control system, the proposed system prevents the controlled object to collide the obstacle, without losing operability. Based on an application example for the one-dimensional assist rollator collision avoidance, this paper reveals the practicality of the proposed system by conducting experiments and the simulations. The result shows the proposed way is one of the effective ways for applying a remote control system to the assist system problem.

著者

神田 康行

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

巻号頁・発行日

vol.85, no.873, pp.19-00035-19-00035, 2019

被引用文献数

1

---

<p>The rigid plastic finite element method (RPFEM) is used in many re-meshing procedures in material processing analysis. Currently, the four-node quadrilateral element, which can avoid volumetric locking, is applied in the RPFEM. However, it is desirable to apply the three-node triangular element instead because of its easy and robust mesh generation procedure. This study applied the three-node triangular element with drilling and strain degrees of freedoms (GNTri3) to the RPFEM, the validity of which was verified by analyzing some numerical examples. First, as verification for the volumetric locking characteristic of the GNTri3, FEM analysis of a nearly incompressible elastic body under plane strain conditions was performed. Volumetric locking was recognized by applying full integration to the element stiffness matrix of the GNTri3. Therefore, it was revealed that the RPFEM using the GNTri3 is necessary for applying selective reduced integration to the element stiffness matrix. Analysis of the RPFEM using the GNTri3 showed that the tool pressure was in good agreement with theoretical solutions and FEM results obtained using a conventional four-node quadrilateral element at a rigid punch indentation. In addition, reasonable material processing deformations were computed in the plane strain compression test.Therefore, validity of the RPFEM using the GNTri3 was verified by numerical results.</p>