Papers - BONKOBARA Yasuhiro
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Vibration Suppression of a Reciprocating Compressor (Investigation Using Fundamental Model)
Memoirs of Faculty of Engineering, University of Miyazaki 47 55 - 59 2018.7
Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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Proposal of self-standing support method for vibration reduction of refrigerator compressors Reviewed
Ko INAGAKI, Yasuhiro BONKOBARA, Takahiro KONDOU, Mie IKE, Takayuki HAMAHATA
Transactions of the JSME (in Japanese) 84 ( 862 ) 1 - 12 2018.6
Language：Japanese Publishing type：Research paper (scientific journal)
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A Ranking Approach to Estimating Structual Damages
Yasuhiro BONKOBARA, Takahiro KONDOU, Yuya HANAUCHI, Takayuki HAMAHATA
Memoirs of Faculty of Engineering, University of Miyazaki 46 77 - 84 2017.7
Language：Japanese Publishing type：Research paper (scientific journal)
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Development of a Tamping Rammer for Decreasing the Risk of Hand-Arm Vibration Syndrome
Yasuhiro BONKOBARA, Takahiro KONDOU, Takayuki HAMAHATA, Daichi INOUE, Kaita MATSUURA
Memoirs of Faculty of Engineering, University of Miyazaki 46 71 - 76 2017.7
Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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Choi M., Kondou T., Bonkobara Y., Yang K.
Journal of Mechanical Science and Technology 30 ( 3 ) 983 - 991 2016.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Mechanical Science and Technology
© 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. We developed a method for analyzing the free vibration of a structure regarded as a distributed system, by combining the Wittrick-Williams algorithm and the transfer dynamic stiffness coefficient method. A computational algorithm was formulated for analyzing the free vibration of a straight-line beam regarded as a distributed system, to explain the concept of the developed method. To verify the effectiveness of the developed method, the natural frequencies of straight-line beams were computed using the finite element method, transfer matrix method, transfer dynamic stiffness coefficient method, the exact solution, and the developed method. By comparing the computational results of the developed method with those of the other methods, we confirmed that the developed method exhibited superior performance over the other methods in terms of computational accuracy, cost and user convenience.
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2E4 Development of Tamping Rammer Using Self-Synchronization Phenomena : Measurement of Impact Force
BONKOBARA Yasuhiro, KAWAMURO Seigo, INOUE Daichi, KONDOU Takahiro, IWAMOTO Nozomu
2014 "2E4 - 1"-"2E4-2" 2014.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers
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IWAMOTO Nozomu, BONKOBARA Yasuhiro, KONDOU Takahiro
Dynamics and Design Conference : D & D 2014 "357 - 1"-"357-9" 2014.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers
The symptoms of a hand-arm vibration syndrome characterized by Raynaud's disease are caused by long-term use of hand-held vibrating tools, and by excessive exposure to hand-arm vibrations. The purpose of this research is to develop a hand-held vibrating tool using self-synchronization phenomena in order to solve the problem of the hand-arm vibration syndrome. We focus on the development of a vibration mechanism for a tamping rammer used to compact cohesive soils and asphalt. The prototype of the generation mechanism of synchronous vibration suitable for a tamping rammer has been developed based on the mechanism of the impact model with four oscillators, which has been developed in the previous reports. This model consists of an upper block and two lower blocks coupled by coil-springs, and two rotor-type oscillators are mounted on each of the lower blocks. The present model generates the synchronous vibration which can achieve a good balance between vibration control on upper block and excitation on lower blocks. In this report, we evaluate the performance both vibration control and excitation of the prototype while the synchronous vibration is generated. The results confirm that the prototype is effective in the prevention of a hand-arm vibration syndrome. However, it is difficult to measure the impact force exactly due to the present experimental system.
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IMAIZUMI Akihiko, KUROKI Hiroyuki, KONDOU Takahiro, BONKOBARA Yasuhiro, TANIGUCHI Tomoyuki, GOTO Toshiro
Dynamics and Design Conference : D & D 2014 "363 - 1"-"363-10" 2014.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers
Machines and structures damaged by aged deterioration or the natural disaster such as the earthquake, and for the certain safe guarantee, the technique attracts attention that indirectly and globally you can estimate the amount of change of the properties of matter level of an element constituting a structure and judge the soundness of the structure quantitatively by measuring the vibration reply of the structure as behavior of the whole structure, and analyzing those data. This technique is called damage identification analysis, that from observation data you analyze having damage or not of the structure, a position of the damage and damage degree. In this study, based on such situation, aiming at the development of the analysis technology that is practical and highly precise, we develop the algorithm of the damage identification analysis using the change of vibration properties as observation data. In this study, we limit the vibration properties as observation data to few natural frequencies of the low level from various kinds of problems as much as possible. In this report, we raise a method to improve estimated precision in the structure damage identification analysis using the Extended Kalman Filter under the limitation that limited the number of the observation data to a few. Furthermore, we examine the prospects of the application for the damage estimate.
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362 Structural Damage Estimation Method with Damage Potential Rankings
GOTO Toshiro, KUROKI Hiroyuki, TANIGUCHI Tomoyuki, IMAIZUMI Akihiko, BONKOBARA Yasuhiro, KONDOU Takahiro
Dynamics and Design Conference : D & D 2014 "362 - 1"-"362-10" 2014.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers
In order to inspect the safety of structures, a non-destructive inspection is required to identify the damaged location. The authors previously developed the structural damage estimation method with damage potential rankings, which is very effective method for decreasing the number of natural frequencies required to detect the damaged part. However, the accuracy of damage estimation decreases by modeling error in case the size of damaged part is too small. Thus, our research proposes a new damage estimation method to bring down the modeling error by appropriately changing the number of modeling division in incremental steps. Then, it becomes possible to perform the high-accuracy estimation regardless of the size of the damaged part. In this report, for the damage estimation problem in a simple straight pipe structure, the validity of the developed algorithm is confirmed by a simple example both numerically and experimentally. As the result, the proposed method can obtain the exact rankings for the risk of damage regardless of the size of the damaged part.
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Tomoki ONO, Takahiro KONDOU, Yasuhiro BONKOBARA
Transactions of the Japan Society of Mechanical Engineers (Series C) 79 ( 799 ) 550 - 561 2013.3
Language：Japanese Publishing type：Research paper (scientific journal)
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ONO Tomoki, KONDOU Takahiro, BONKOBARA Yasuhiro
Journal of System Design and Dynamics 7 ( 4 ) 580 - 594 2013
Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers
The present paper investigates the effects of a coupling element placed between nonlinear self-excited oscillators on synchronization. A simple nonlinear model is newly developed by modifying the model treated in our previous report. This model consists of two oscillators subjected to Coulomb friction and a block installed in the coupling element. These elements are connected in series by coil springs and dashpots. In this model, stick-slip motion frequently occurs due to Coulomb friction. The synchronized solutions and the stability are analyzed accurately by the improved shooting method. The new model is validated by comparing the calculated results and the experimental results, and the features of the synchronized solutions are investigated. The results reveal that the frequencies and vibratory patterns closely correspond to the natural frequencies and natural modes of a three-degree-of-freedom system without Coulomb friction and that the existence regions of the synchronized solutions depend on the block mass as a parameter of the coupling element. When the parameter is set appropriately, the existence regions expand. The mechanism behind this is examined from the viewpoint of the energy transition between oscillators.
DOI： 10.1299/jsdd.7.580
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Tomoki ONO, Takahiro KONDOU, Yasuhiro BONKOBARA
Journal of System Design and Dynamics 6 ( 4 ) 494 - 510 2012.8
Language：English Publishing type：Research paper (scientific journal)
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Myung-Soo CHOI, Takahiro KONDOU and Yasuhiro BONKOBARA
Journal of Mechanical Science and Technology 26 ( 1 ) 11 - 19 2012.1
Language：English Publishing type：Research paper (scientific journal)
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SA/GA Hybrid Optimization Method Using a Procedure of Mesh Size Change Reviewed
Yuichiro SAKAMOTO, Yasuhiro BONKOBARA, Takahiro KONDOU, Kenji ABE, Tomoyuki TANIGUCHI
Transactions of the Japan Society of Mechanical Engineers (Series C) 77 ( 784 ) 4367 - 4381 2011.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Synchronization in Coupled Nonlinear Self-Excited Oscillators with Stick-Slip Vibration Reviewed
Tomoki ONO, Takahiro KONDOU and Yasuhiro BONKOBARA
Proceeding of 14th Asia Pacific Vibration Conference 3 1513 - 1522 2011.12
Language：English Publishing type：Research paper (international conference proceedings)
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Simultaneous Optimization for Topology and Geometry of a Two Dimensional Framed Structure Using SA/GA Hybrid Method Reviewed
Yuichiro SAKAMOTO, Yasuhiro BONKOBARA, Takahiro KONDOU, Hiroyuki KUROKI
Proceeding of 14th Asia Pacific Vibration Conference 3 1185 - 1193 2011.12
Language：English Publishing type：Research paper (international conference proceedings)
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Development of a Tamping Rammer Using Self-Synchronization Phenomena Reviewed
Yasuhiro BONKOBARA, Takahiro KONDOU, Tomoki ONO
Proceeding of 14th Asia Pacific Vibration Conference 3 1473 - 1482 2011.12
Language：English Publishing type：Research paper (international conference proceedings)
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Multiple Damage Identification Analysis Based on Filtering Theory for a Framed Structure by Using Low Order Natural Frequency Change Reviewed
Hiroyuki KUROKI, Takahiro KONDOU, Yasuhiro BONKOBARA, Yuichiro SAKAMOTO
Proceeding of 14th Asia Pacific Vibration Conference 3 1493 - 1502 2011.12
Language：English Publishing type：Research paper (international conference proceedings)
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Yasuhiro BONKOBARA, Tomoki ONO, Takahiro KONDOU
Journal of System Design and Dynamics 5 ( 6 ) 1361 - 1375 2011.9
Language：English Publishing type：Research paper (scientific journal)
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Yuichiro SAKAMOTO, Yasuhiro BONKOBARA, Takahiro KONDOU
Transactions of the Japan Society of Mechanical Engineers (Series C) 77 ( 781 ) 3454 - 3468 2011.9
Language：Japanese Publishing type：Research paper (scientific journal)