Transactions of the JSME (in Japanese)

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EISSN : 2187-9761
Published by: Japan Society of Mechanical Engineers (10.1299)
Total articles ≅ 2,975
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Tamotsu Murakami, Tatsuya Kure, Yuta Matsunaga
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00207

Abstract:
Recently in the field of design, it is becoming more important to generate innovative ideas of "what to create" at early design stage than ideas of "how well to make". Ideation informatics to enhance idea generation by adding systematicity and exhaustiveness of information technology to human intuition should be a prospective approach to the problem. In this research, a ten sentence pattern model is proposed as a computable description of function and user experience (UX) at early design stage as a fundamental technology for ideation informatics by extending the English basic five sentence patterns. An XML format is designed to add semantic information to words, phrases, and sentences described in the ten sentence pattern model by using concept dictionary, i.e., concept identifiers of EDR electronic dictionary and synsets of Japanese WordNet, and software to calculate their semantic similarity is implemented in Python. Then, based on the knowledge of cognitive neuroscience that "human creation does not create something out of nothing, but the memory of the past is the basis of creation", a database of functions and UXs of existing products and services is prepared as an extension of human memory. Using the database, experiments to coming up ideas for solving problems related to the new coronavirus. From the obtained results, the effectiveness and possibility of the proposed method are confirmed.
Chikako Natsumeda, Kazumi Matsui, Junichi Tatami, Takahiro Yamada
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00237

Abstract:
In this paper, a simple simulation strategy for sintering ceramics is proposed by referring to the experimental results of the deformation profile obtained from a thermomechanical analysis (TMA) under uniaxial compression loads. Assuming that mechanical and thermal deformations are independent, the total deformations are decomposed into mechanical and thermal components, and each deformation component is divided into reversible and irreversible deformations. The thermal and mechanical reversible deformations are represented by the commonly accepted models, namely thermal expansion and linear elasticity. For the thermal irreversible strain (sintering strain), the Master Sintering Curve (MSC), which considers microscopic thermodynamics from a macroscopic perspective, is employed. This facilitates the prediction of any densification evolution without stress and decreases the number of experiments required for parameter fittings. The viscoplasticity model is used for the mechanical irreversible strain to represent the creep deformation in sintering ceramics under stress. In this model, the temperature dependence of the viscosity parameter and density dependence of the yield stress are introduced. The sintering simulation was performed by installing a model with a User Programmable Feature (UPF) into ANSYS thermal–structural analysis. The simulations were validated by comparing the simulation deformation profiles with other sintering experiments under uniaxial compression loads that were not used for the modeling.
Ryo Takahashi, Takao Goto, Yutaro Nonaka, Tadashi Egami
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00128

Abstract:
We developed a new H-type climber for infrastructure inspection by applying the manufacturing technology for climbers used in space elevator experiments, which have been researched for many years. This inspection climber ascends and descends two belt tethers stretched in parallel, thereby reducing the degrees of freedom around each belt and making the climber more resistant to external disturbances such as wind and to twisting than when ascending and descending a single belt. The climber could move not only vertically but also horizontally and on inclines such as slopes. In addition, multiple climbers could be connected to each other by an aluminum frame, which has the advantage that various inspection units can be installed for versatile inspection. In this development work, we first conducted an experiment to investigate a drive system suitable for transporting heavy objects, and then developed the new climber for infrastructure inspection based on the results obtained. In addition, an optimal synchronous control system for position and velocity was developed as an alternative to the conventional optimal synchronous control system for position alone in order to keep the tilt of the inspection climber horizontal and to control its speed. The climber and control system were verified through simulations as well as actual experiments.
Yuta Wakabayashi, Jun Kinugawa, Masaya Kamioka, Kazuhiro Kosuge
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00123

Abstract:
In logistics warehouses, Goods-to-Person systems (i.e., kitting transport systems) and workers work together in order to improve the efficiency of kitting (also called “picking”) tasks. On the other hand, in assembly factories that also require kitting tasks, Goods-to-Person systems have not yet been implemented. We propose a novel robot co-worker called Kitting Parts Delivery system (i.e., KitPaDY) to expedite work processes at assembly factories. Unlike existing Goods-to-Person systems that are designed to use a mobile robot to transfer a single shelf at a time, KitPaDY adopts a novel mechanism that enables a single mobile robot to transfer multiple shelves simultaneously. The mechanism is mounted on every shelf and does not need any power. Rather, it uses the drive of a mobile robot to group shelves together; this also simplifies the control of the mobile robot. Here, we describe the mechanism behind KitPaDY and the mobile robot’s motion. Furthermore, we conducted an experiment to gauge KitPaDY’s ability to simultaneously transport multiple shelves. Additionally, by comparing KitPaDY with existing transport systems for current kitting processes, we demonstrated our system’s efficacy in the simulations. The simulation results show that KitPaDY can reduce the required number of mobile robots by 75% compared to existing transport systems.
Yuta Kasuya, Naoki Iinuma, Ryo Shirata, Hiroshige Sato, Yasuhiro Kakinuma
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00172

Abstract:
Ultrasonic abrasive machining is a machining method in which an ultrasonically-vibrated tool presses the workpiece via free abrasive grains and induces hammering motion of free abrasives. This machining technique is especially applicable to hard-and-brittle materials such as ceramic matrix composites and sufficient machining speed is practically achieved by performing micro-brittle fractures tens of thousands of times per second. Nevertheless, there are few studies that quantitatively evaluate the parameters of this machining method and their interactions. The problem is that this machining process is conducted manually and the machining conditions are determined by the experience of an operator. Hence, derivation of conditions to improve machining efficiency is required. In this study, the factor effects and their interactions among machining pressure, oscillator power and slurry flow, which are the typical parameters of ultrasonic abrasive machining, were evaluated by analysis of variance and the related experiments in monolithic SiC. As a result of analysis of variance and the related experiments, it was shown that the combination of machining pressure of 135 g/mm2, oscillator power of 100 W and slurry flow of 2500 mL/min remarkably improves the machining efficiency in monolithic SiC. It was also clarified that there are significant interactions between the machining pressure and the oscillator power and between the machining pressure and the slurry flow, respectively.
Wanjun Zhang, Masayuki Arai, Kiyohiro Ito
Transactions of the JSME (in Japanese), Volume 87, pp 21-00086; https://doi.org/10.1299/transjsme.21-00086

Abstract:
Thermal barrier coating (TBC) is widely applied to gas turbine blade surface to protect the metallic substrate from high-temperature combustion gas flow. Porous TBC system has been developed by our research group in order to further increase the turbine inlet temperature. In this study, in order to appropriately evaluate the stress distribution and the crack growth behavior in porous TBC subjected to a monotonical tensile loading at high-temperature, a finite element analysis model with pores in top coat (TC) based on an actual cross-sectional image of TBC specimen was established. The inelastic constitutive equation of TC and the crack growth algorithm proposed by our research group were also introduced into the analysis model. It was confirmed that the stress distribution and the crack growth behavior obtained by the analysis under a monotonical tensile loading condition were consistent with the experimental results under 293K and 1273K temperature conditions. In addition, the analysis results from three models with different porosity showed that the crack initiation strain is increased with increasing the porosity. The increase of porosity could improve the apparent ductility of TC. It was considered that the improved ductility suppressed the cracks initiation.
Kohei Shintani, Hideyuki Azegami, Takayuki Yamada
Transactions of the JSME (in Japanese), Volume 87, pp 21-00138; https://doi.org/10.1299/transjsme.21-00138

Abstract:
This paper proposes a solution to a multi-material robust topology optimization problem of density type considering material uncertainties based on H1 gradient method. A material interpolation with respect to the density is introduced using the rational approximation of material properties (RAMP) and generalized it for the case with an arbitrary number of materials. Material uncertainty is considered by introducing random variables in the material interpolation scheme. The probability density functions of the random variables are assumed to be given. The topology optimization is formulated using the density which is given by a sigmoid function of the design variable. A weighted sum of the mean and standard deviation of the mean compliance is used as the objective function to control the tradeoff between optimality and robustness. To evaluate statistical moments of the objective function effectively, the univariate dimension reduction (UDR) and the Gauss-type quadrature sampling are introduced. A scheme to solve the robust topology optimization problem is presented using an iterative algorithm based on the H1 gradient method for reshaping. Examples of a two-dimensional cantilever beam under various material uncertainty exhibit the efficiency and flexibility of the approach. The accuracy of UDR is validated by comparing the results to the Monte Carlo approach.
Yosuke Horie, Katsuhiko Kimura, Akihiro Nojima, Hiroyuki Takayama, Kohei Nonaka
Transactions of the JSME (in Japanese), Volume 87, pp 21-00079; https://doi.org/10.1299/transjsme.21-00079

Abstract:
As a method for cleaning the nozzle of clinical analyzers with high cleaning efficiency, ultrasonic cleaning was selected because the cleaning mechanism can be miniaturized and the effect on dispensing accuracy is negligible. As for nozzle cleaning, it is necessary to meet two requirements: (i) suppress the wetting range of the nozzle inserted in the chamber of the ultrasonic cleaner and (ii) generate cavitation at a depth of a few millimeters from the liquid surface. To meet those requirements, a new ultrasonic cleaner with an L-shaped cleaning head as a small and high-efficiency cleaning nozzle is proposed. The shape of the cleaning head, which enables the vibration phase of the ultrasonic irradiation surfaces to be reversed even with a single ultrasonic transducer (BLT), is composed of two vibration plates at the tip of the cleaning head to concentrate the sound pressure in the cleaning area. The BLT with cleaning head has three resonant frequencies: fBLT, fL-P, and fU-P. At fBLT, the ultrasonic transducer expands and contracts in the longitudinal direction.At fL-P and fU-P, deformation of each vibration plate is large. By setting the resonance frequencies in the increasing order of magnitude fL-P, fBLT, and fU-P, the phases of the two vibration plates are reversed by driving at fBLT. It was confirmed by experiment that the sound pressure can be concentrated in the cleaning area by driving the cleaning head at fBLT.
Akitoshi Fujita, Kiyomi Kawamura, Reiko Ueda
Transactions of the JSME (in Japanese); https://doi.org/10.1299/transjsme.21-00118

Abstract:
This study proposed a simple configuration for a Variable Injection Direction (VID) nozzle for a diesel engine, which can change a direction of fuel injection according to the needle lift amount. Differently from a conventional one, the VID nozzle has a needle tip partly cylindrically shaped, and a divergent-shaped hole-end. The geometry enables to control internal nozzle flow. The needle tip increases the angle of the flow direction to a hole inlet with respect to an axis of nozzle hole at small needle lift, while it decreases the angle at large needle lift. The divergent-shaped hole-end allows for those direction change of injection. The internal nozzle flow was numerically simulated for exploring the nozzle geometry in detail, using the computational fluid dynamics (CFD). Also, for its validation, an eight-times enlarged nozzle was developed and water was injected. The observation was conducted using a high speed video camera. The CFD results showed good agreement with the measurements regarding not only the injection direction but also the needle lift amount when the injection direction switches. The investigations confirmed that the injection direction can be changed within one injection and a magnitude of injection angle is controllable by the nozzle geometry.
Kazuki Harada, Shion Ando, Yuya Ito, Yuzo Kawasoe, Hideki Hashimoto, Osamu Moriue
Transactions of the JSME (in Japanese), Volume 87, pp 21-00168; https://doi.org/10.1299/transjsme.21-00168

Abstract:
While lean combustion in SI engine is one of the promising methods to increase the thermal efficiency and reduce the pollutant emissions, it causes instability of ignition and combustion due to the low burning velocity. Thus, we propose to increase the combustion intensity by incorporating oxygen enrichment with lean combustion. The objective of present study is to investigate the effects of oxygen enrichment on lean combustion behavior in SI engine. Premixed methane-air-oxygen mixture was combusted in a rapid compression expansion machine with varying their concentration. Experimental conditions were determined by identifying the conditions where the laminar burning velocity significantly changes by oxygen enrichment with 1-D simulation of premixed combustion. Histories of pressure were measured to evaluate heat release rate. Luminous flame was captured by a high-speed camera to observe the flame propagation. As a result, laminar burning velocity increased with oxygen concentration, which caused reduction of combustion period and enhancement of the indicated thermal efficiency. On the other hand, this trend was suppressed when the fuel concentration is lower than 6.85 %. In addition, when the fuel concentration is relatively large, flame propagation speed increased with increase in oxygen concentration, which can cause autoignition of end gas. NOx emission decreased or kept almost constant with increase in oxygen concentration, which might be due to the shortened combustion duration.
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