OBUNAI Kiyotaka
Faculty of Science and Engineering Department of Mechanical and Systems Engineering
Professor
Last Updated :2025/05/20

Researcher Profile and Settings

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Machine materials and mechanics

Research Experience

  • University of Nebraska–Lincoln, Department of Mechanical and Materials EngineeringLincoln, Visiting Adjunct Faculty Member, 2023/04 - 2024/09
  • Doshisha University, Faculty of Science and Engineering Department of Mechanical and Systems Engineering, Professor, 2024/04 -
  • Doshisha University, Faculty of Science and Engineering Department of Mechanical and Systems Engineering, 准教授, 2018/04 - 2024/03
  • Okayama Prefectural University, Faculty of Computer Science and System Engineering, Assistant Professor, 2011/04 - 2018/03
  • Japan Society for the Promotion of Science, Research Fellowship for Young Scientists, 2010/04 - 2011/03

Awards

  • JSMS Award for Promising Researchers
    May 2022, Society of Materials Science, Japan
  • JSMS Kansai Branch President Award
    Apr. 2022, Society of Materials Science, Japan
  • Research and Development Award
    Jul. 2017, The Japan Institute of Light Metals Chugoku-Shikoku Chapter
  • Encouragement award
    May 2015, JSMS Committee on Composite Materials

Published Papers

  • Mechanical characteristics of reclaimed carbon fibre under superheated steam atmosphere and its feasibility for remanufacturing CFRP/CFRTP
    K. Obunai; K. Okubo
    Composites Part A: Applied Science and Manufacturing, Elsevier BV, 176 107843 - 107843, Jan. 2024, Scientific journal
  • Effect of Insertion of Controlled Composition Gradient Layer on Mechanical Characteristics of Composite Specimens Made by FDM Type 3D Printer Equipped with Co-axial Extruder
    Kiyotaka Obunai; Kazuya Okubo; Kazuki Sanada
    Seikei-Kakou, The Japan Society of Polymer Processing, 36(1) 31 - 38, 20 Dec. 2023, Scientific journal
  • Change of Relative Local Velocity in Pulley Groove at Sliding between Belt and Pulleys for Metal Pushing V-Belt Type CVT
    Taku Kamiya; Kiyotaka Obunai PhD; Kazuya Okubo
    SAE Technical Paper Series, SAE International, 24 Oct. 2023, International conference proceedings
  • A prediction model of flat belt slippage considering rigid-slip during power transmission
    OBUNAI Kiyotaka; OKUBO Kazuya; FUKUO Ato
    Transactions of the JSME (in Japanese), The Japan Society of Mechanical Engineers, 89(924) 23-00073 - 23-00073, 2023
  • 炭素繊維/樹脂間の界面接着せん断強度に及ぼす繊維表面のサイジング処理効果の負荷ひずみ速度の違いによる変化—Change in Effects of Sizing Treatment on Interfacial Shear Strength between Carbon Fiber and Resin According to Difference of Loading Strain Rate
    村山 凌太郎; 小武内 清貴; 大窪 和也
    日本接着学会誌 = Journal of the Adhesion Society of Japan : adhesion, 日本接着学会, 59(3) 65 - 72, 2023
  • Effect of sub-micron glass fiber addition on CAI strength of UD-CFRP
    Ryotaro Murayama; Kiyotaka Obunai; Kazuya Okubo
    International Journal of Computational Methods and Experimental Measurements, WITPRESS LTD., 10(3) 271 - 281, 14 Sep. 2022, Scientific journal
  • Orbital Change of belt for Metal V-belt Type CVT (Continuously Variable Transmission) - Change of pitch angle at strings -
    Kazuki Oshima; Seiji Mitsubayashi; Kiyotaka Obunai; Kazuya Okubo
    IOP Conference Series: Materials Science and Engineering, IOP Publishing, 1250(1) 012001 - 012001, 01 Jul. 2022, Scientific journal
  • Local change of PV value on end faces of rocker pins of chain type CVT (Continuously Variable Transmission) under transmitting condition
    Ryunosuke Kikui; Kiyotaka Obunai; Kazuya Okubo; Kouhei Toyohara; Kyohei Watanabe; Hui Jin
    SAE Technical Papers, 09 Jan. 2022, International conference proceedings
  • Influence of Deformation of Elements in Width Direction on Winding Radial Displacement in Pulley Groove of Metal V-belt Type CVT
    Mitsubayashi Seiji; Hachiman Itsuki; Obunai Kiyotaka; Okubo Kazuya
    Transactions of Society of Automotive Engineers of Japan, Society of Automotive Engineers of Japan, 53(6) 1033 - 1038, 2022
  • Skew of Frictional Power Transmission Flat Belt Driven by Pulleys with In-Plane Angular Misalignment
    MITSUBAYASHI Seiji; TSUTSUMI Kota; OBUNAI Kiyotaka; OKUBO Kazuya
    JOURNAL OF JAPAN SOCIETY FOR DESIGN ENGINEERING, Japan Society for Design Engineering, advpub, 2022
  • Influence of Bending-Twisting Coupling Deformation on Pure Bending Strength and Fracture Morphology of CFRP Angle-Ply Laminate
    Kazuki Terasaki; Kiyotaka Obunai; Kazuya Okubo
    Materials Science Forum, 1067 99 - 105, 2022, In book
  • Influence of Deformation of Elements in Width Direction on Winding Radial Displacement in Pulley Groove of Metal V-belt Type CVT
    三林誠治; 八幡樹; 小武内清貴; 大窪和也
    自動車技術会論文集(Web), 53(6), 2022
  • Change of Internal Force State in Element for Metal V-belt Type CVT Due to Increase of Transmitting Torque
    Mitsubayashi Seiji; Hachiman Itsuki; Obunai Kiyotaka; Okubo Kazuya
    Transactions of Society of Automotive Engineers of Japan, Society of Automotive Engineers of Japan, 53(4) 731 - 736, 2022
  • Improvement in Impact Energy Absorption of UD-CFRP by Sub-Micron Glass Fiber into Its Matrix
    Ryotaro Murayama; Kiyotaka Obunai; Kazuya Okubo; Li Bao
    Open Journal of Composite Materials, Scientific Research Publishing, Inc., 11(04) 82 - 93, Oct. 2021, Scientific journal
  • 竹繊維の利活用 : その可能性を探る (天然素材関連特集)
    藤井 透; 大窪 和也; 小武内 清貴
    強化プラスチックス, 強化プラスチック協会, 67(8) 329 - 335, Aug. 2021
  • Improvement of Impact Energy Absorption of Curved Thin Chopped Tape CFRP Shell by Adding Submicron Glass Fiber into Matrix
    Taiki Ueda; Kazuya Okubo; Kiyotaka Obunai; Li Bao
    Key Engineering Materials, Trans Tech Publications, Ltd., 889 59 - 64, 16 Jun. 2021, Scientific journal
  • Frictional Loss Mechanism Due to Polygonal Winding Slip of Chain Type CVT
    Yuichi Nakai; Kiyotaka Obunai; Kazuya Okubo; Junpei Hayakawa; Kouhei Toyohara; Takeshi Muramatsu
    Journal of Physics: Conference Series, IOP Publishing, 1888(1) 012011 - 012011, 01 Apr. 2021, Scientific journal
  • チェーン式CVTの多角巻付きに伴う摩擦損失
    菊居龍之介; 大窪和也; 小武内清貴; 豊原耕平; 早川純平; 渡邊恭平; 村松剛; 金暉
    年次大会, 一般社団法人 日本機械学会, 2021, 2021, Scientific journal
  • Influence of axial pulley misalignment on power loss in layered steel bands and of metal V-belt type CVT
    Daiki Murai; Tooru Yagasaki; Kazuya Okubo; Kiyotaka Obunai
    2021 IEEE Asia-Pacific Conference on Computer Science and Data Engineering, CSDE 2021, IEEE, 2021, International conference proceedings
  • Improving Damping Properties of Carbon Fiber Reinforced Plastic Fabricated with Modified Matrix by Adding Cellulose Nanofibers : Influence of Aspect Ratio of Cellulose Nanofiber Added to Matrix on Damping Properties
    野村知正; 小武内清貴; 大窪和也
    日本複合材料学会誌, 日本複合材料学会, 47(4) 131 - 136, 2021
  • Effect of Heating Process on Flexural Strength and Toughness of CFRTP Molded by Multi-layer Press -Investigation on Effect of Residual Stress-
    Akihito Itami; Kiyotaka Obunai; Kazuya Okubo; Hiroyuki Takei
    IOP Conference Series: Materials Science and Engineering, 859(1), 28 May 2020, International conference proceedings
  • Effect of Submicron Glass Fiber Modification on Mechanical Properties of Short Carbon Fiber Reinforced Polymer Composite with Different Fiber Length
    Nhan Thi Thanh Nguyen; Obunai Kiyotaka; Okubo Kazuya; Fujii Toru; Shibata Ou; Tomokuni Hidehiko; Fujita Yukiko
    Journal of Composites Science, MDPI AG, 4(1) 5 - 5, 02 Jan. 2020, Scientific journal
  • 超音波応用加工技術 1)超音波ニードルパンチ処理によるCFRTPの面外特性の向上
    小武内清貴; 福田忠生; 尾崎公一
    超音波Techno, 32(6), 2020
  • Improvement of Fatigue Life of Plain Woven CFRP plate by Adding Cellulose Nano Fibers and Investigation on Its Mechanism
    OBUNAI Kiyotaka; OKUBO Kazuya; HAYASHI Kenta
    Journal of the Society of Materials Science, Japan, The Society of Materials Science, Japan, 69(5) 351 - 357, 2020, Scientific journal
  • Brittle failure criteria of CNRB specimen for fracture toughness test
    Manato KANESAKI; Kiyotaka OBUNAI; Tadao FUKUTA; Yoshihito KUROSHIMA; Koichi OZAKI
    Mechanical Engineering Journal, Japan Society of Mechanical Engineers, 7(4) 19 - 00621, 2020, Scientific journal
  • Consideration and Practice of an Effective Promotion System for Multi-Industry-Academia Collaboration in the Automobile Industry
    Akihiro Aoyama; Kiyotaka Obunai; Kazuya Okubo
    同志社大学ハリス理化学研究報告 = The Harris science review of Doshisha University, Harris Science Research Institute of Doshisha University, 60(4) 185 - 193, Jan. 2020
  • Improvement of Interfacial Properties and Fatigue Life by High Polarization of Epoxy Matrix of CFRP
    松田 遼亮; 小武内 清貴; 大窪 和也; 河村 奈緒
    強化プラスチックス, 強化プラスチック協会, 66(1) 30 - 35, Jan. 2020
  • Effect of Ultrasonic Needle Punching on Interlaminar Tensile Strength and Mode I Interlaminar Fracture Toughness of Unidirectional CFRTP Laminate
    NISHIHARA, Iori; OBUNAI, Kiyotaka; KANESAKI, Manato; FUKUTA, Tadao; OZAKI, Kouichi
    Advanced Experimental Mechanics, 日本実験力学会, 5, 2020, Scientific journal
  • Effects of imparting polarity to epoxy matrix of carbon fiber reinforced plastic on static, impact and fatigue properties
    Ryosuke Matsuda; Kiyotaka Obunai; Kazuya Okubo; Nao Deguchi
    APFIS 2019 Proceedings - 7th Asia-Pacific Conference on FRP in Structures, 01 Dec. 2019, International conference proceedings
  • Projection-transformation method with considering energy conservation
    Hitoshi Yamauchi; Koichi Ozaki; Yoichiro Sato; Tadao Fukuta; Kiyotaka Obunai
    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, WILEY, 14(12) 1805 - 1814, Dec. 2019, Scientific journal
  • 産業用ベルト伝動の基礎と伝動設計 (特集 動力伝達技術)
    大窪 和也; 小武内 清貴
    月刊トライボロジー, 新樹社, 33(12) 39 - 41, Dec. 2019
  • セルロースナノファイバー(CNF)の添加によるCFRPの疲労寿命の改善事例 (セルロースナノファイバー関連特集)
    大窪 和也; 小武内 清貴; 田中 亜弥
    強化プラスチックス, 強化プラスチック協会, 65(11) 462 - 465, Nov. 2019
  • Mechanical Properties of Submicron Glass Fiber Reinforced Vinyl Ester Composite
    Nguyen T. T. Nhan; K. Obunai; K. Okubo; O. Shibata; H. Tomokuni; Y. Fujita
    Open Journal of Composite Materials, Scientific Research Publishing, Inc., 09(04) 365 - 377, Oct. 2019, Scientific journal
  • Mechanical Characteristics of Composite Reinforced by Short and Plain Woven Carbon Fiber with Vinyl Ester Matrix Modified by Submicron Glass Fiber
    Thi Thanh Nhan Nguyen; Kiyotaka Obunai; Kazuya Okubo; Ou Shibata; Hidehiko Tomokuni; Yukiko Fujita
    同志社大学ハリス理化学研究報告 = The Harris science review of Doshisha University, Harris Science Research Institute of Doshisha University, 60(3) 127 - 132, Oct. 2019
  • Impact Improvement of Tape Carbon Fiber Composite Modified by Submicron Glass Fiber
    Nhan T.T. Nguyen; Naoto Miyakita; Obunai Kiyotaka; Okubo Kazuya
    Journal of Materials Science Research, Canadian Center of Science and Education, 8(4) 21 - 21, 30 Sep. 2019, Scientific journal
  • Effects of submicron glass fiber addition on mechanical property of short carbon fiber reinforced vinyl ester resin
    Nguyen T.T. Nhan; K. Obunai; K. Okubo; Y. Fujita
    ICCM International Conferences on Composite Materials, 2019-August, 2019, International conference proceedings
  • Improvement of Static and Fatigue Durability of CFRTP Joint Using Bite Plate and Modified PP Film
    SHIOYA Wataru; OBUNAI Kiyotaka; OKUBO Kazuya; ISHIKAWA Takeshi
    Journal of the Japan Society for Composite Materials, The Japan Society for Composite Materials, 45(6) 230 - 235, 2019
  • Consideration of Industry-University Collaborative Research Framework in Drivetrain System
    Aoyama Akihiro; Obunai Kiyotaka; Okubo Kazuya
    Transactions of Society of Automotive Engineers of Japan, Society of Automotive Engineers of Japan, 50(5) 1307 - 1312, 2019
  • Industry-Academia Collaborative Research on Air Bubble Control in Oil in Vehicle power transmission system and Consideration
    Aoyama Akihiro; Obunai Kiyotaka; Okubo Kazuya
    Transactions of Society of Automotive Engineers of Japan, Society of Automotive Engineers of Japan, 50(6) 1543 - 1548, 2019
  • Low Cycle Fatigue Life Estimation of Stainless Steel
    OBUNAI, Kiyotaka; KAWASE, Koshiro; FUKUTA, Tadao; OZAKI, Koichi
    Advanced Experimental Mechanics, 日本実験力学会, 3 152 - 156, Aug. 2018, Scientific journal
  • 竹から散りだした繊維を複合材料の強化材として使う
    藤井透; 大窪和也; 小武内 清貴; wenpeng Yu; Wenbin Yao
    JATAFFジャーナル, 6(8) 36 - 43, 19 Mar. 2018
  • Effective diameter of added glass fiber into matrix of carbon fiber reinforced thermo-plastics for improving mechanical properties
    Naoto Miyakita; Kazuya Okubo; Kiyotaka Obunai; Kazuya Yanagita
    33rd Technical Conference of the American Society for Composites 2018, 5 3042 - 3048, 2018, International conference proceedings
  • Improvement of Interfacial Adhesion Strength and MechanicalProperties of CFRP by Fabricated with Modified Matrix byAdding Nano Fibers
    HAYASHI Kenta; OKUBO Kazuya; OBUNAI Kiyotaka
    Journal of The Adhesion Society of Japan, The Adhesion Society of Japan, 54(11) 402 - 409, 2018
  • Effect of Residual Stress in Composites onits Interlayer Adhesive Strength
    OBUNAI Kiyotaka; NISHIHARA Iori; FUKUTA Tadao; OZAKI Koichi
    Journal of The Adhesion Society of Japan, The Adhesion Society of Japan, 54(11) 410 - 415, 2018
  • Study on AZ91D chip for injection molding (2nd Report, Effect of dimension on effective thermal conductivity after consolidation)
    OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Transactions of the JSME (in Japanese), The Japan Society of Mechanical Engineers, 84(863) 18 - 00106-18-00106, 2018
  • Microstructure and mechanical properties of newly developed SiC-C/C composites under atmospheric conditions
    Kiyotaka Obunai; Daisuke Mikami; Tadao Fukuta; Koichi Ozaki
    AIMS Materials Science, AIMS Press, 5(3) 494 - 507, 2018, Scientific journal
  • Study of Numerical Calculation for Laser Beam Joining Process
    OBUNAI Kiyotaka; MATSUMOTO Takuya; FUKUTA Tadao; OZAKI Koichi
    Journal of The Adhesion Society of Japan, The Adhesion Society of Japan, 53(6) 217 - 222, 2017
  • Goal Setting in a PBL Class Considering Variety of Solutions
    IZUMI Shinsaku; ISHII Yutaka; YAMASAKI Taiga; FUKUTA Tadao; SHIBA Seiji; OBUNAI Kiyotaka
    Journal of JSEE, Japanese Society for Engineering Education, 65(6) 6_103 - 6_108, 2017
  • Tensile properties of Nitriding Tantalum
    Yusaku Wada; Kiyotaka Obunai; Tadao Fukuta; Hitoshi Yamauchi; Koichi Ozaki
    Advanced Experimantal Mechanics, 1 137 - 142, Aug. 2016, Scientific journal
  • Mechanical Characteristics of C/C Composites Modified with Micro-Sized Glass Fibers
    Yasuhiro Utsunomiya; Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki; Kazuya Okubo; Toru Fujii
    Advanced Experimental Mechanics, 1 126 - 130, Aug. 2016
  • Effect of Thin TaN on Tensile Characteristics of Tantalum
    Yusaku Wada; Kiyotaka Obunai; Tadao Fukuta; Hitoshi Yamauchi; Koichi Ozaki
    Advanced Experimental Mechanics, 1 137 - 142, Aug. 2016
  • 超音波ニードルパンチ処理を施したCFRTPのMode Ⅰ層間破壊じん性と曲げ強度
    森川 祥文; 小武内 清貴; 福田 忠生; 尾崎 公一
    自動車技術会論文集, 自動車技術会, 47(3) 801 - 806, May 2016
  • Effect of hot needle punching on bending and inter-laminar characteristics of CF/PA6 composite
    Obunai Kiyotaka; Fukuta Tadao; Ozaki Koichi; Morikawa Yoshifumi
    MECHANICAL ENGINEERING JOURNAL, The Japan Society of Mechanical Engineers, 3(4) 15 - 00610-15-00610, 2016, Scientific journal
  • Development of green composites using decomposed bamboo powder
    Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki; Sayaka Ikeno
    International Jornal of Engineering Sciences & Reserch Technology, 4(12) 171 - 176, Dec. 2015, Scientific journal
  • Carbon fiber extraction from waste CFRP by microwave irradiation
    K. Obunai; T. Fukuta; K. Ozaki
    COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING, ELSEVIER SCI LTD, 78 160 - 165, Nov. 2015, Scientific journal
  • Decomposition of bamboo powder for eco-friendly material development by using superheated steams
    Sayaka Ikeno; Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki
    Advances in Materials, 4(5-1) 1 - 6, Oct. 2015, Scientific journal
  • Assessing the Educational Effectiveness of Human Resource Development Education with Information System Engineers through a Rescue Robot Contest
    Tadao FUKUTA; Yoshihiro SEJIMA; Kiyotaka OBUNAI; Hitoshi YAMAUCHI; Toshiki MATSUI
    Journal of Japanese Society for Engineering Education, Japanese Society for Engineering Education, 63(5) 87 - 92, Sep. 2015, Scientific journal
  • Optimum Rib Installation Conditions on Air Exhaust from Backward Step Part by Visualizing Water Flow Experiments
    Tadao FUKUTA; Kiyotaka OBUNAI; Koichi OZAKI
    Journal of Japan Foundry Engineering Society, Japan Foundry Engineering Society, 87(7) 446 - 452, Jul. 2015, Scientific journal
  • Study on AZ91D chip for injection molding (1st Report, Effect of dimension on bulk density after consolidation)
    OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, The Japan Society of Mechanical Engineers, 81(830) 15 - 00259-15-00259, 2015
  • Improvement of tensile properties of injection molded AZ91D alloy by adding Carbon Black
    Seiichi Akazawa; Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Koji Murakami
    Keikinzoku/Journal of Japan Institute of Light Metals, Japan Institute of Light Metals, 65(4) 113 - 117, 2015, Scientific journal
  • Hydrogen Embrittlement Properties of an Al-Mg-Zn Series of Alloy with Brilliant
    Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Akihiro Tanabe; Hideki Kanetsuki; Koji Murakami; Makoto Hino
    JOURNAL OF THE JAPAN INSTITUTE OF METALS, JAPAN INST METALS, 79(3) 94 - 99, 2015, Scientific journal
  • Prediction Method of Fracture Strain for Non-Standardized Specimens Based on Local Absorbed Strain Energy Distribution
    FUKUTA, Tadao; OBUNAI, Kiyotaka; OZAKI, Koichi; TSUTSUI, Masato; HARA, Takuto
    実験力学, 日本実験力学会, 14(Special_Issue) 210 - 215, Sep. 2014, Scientific journal
  • First-Principles estimation of hydrogen embrittlement properties at the grain boundary of an Al-Mg-Zn series alloy
    Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Kosuke Kitaura; Akihiro Tanabe
    Zairyo/Journal of the Society of Materials Science, Japan, 63(2) 174 - 181, Feb. 2014, Scientific journal
  • 混練・複合化技術 2
    小武内清貴
    成形加工, 一般社団法人 プラスチック成形加工学会, 26(5), 2014, Scientific journal
  • Synthesization of CNTs on pore surfaces in C/C composites and effect of CNTs on tribological characteristics
    Kiyotaka Obunai; Kazuya Okubo; Toru Fujii
    Zairyo/Journal of the Society of Materials Science, Japan, Society of Materials Science Japan, 63(5) 356 - 361, 2014, Scientific journal
  • Influence of molding conditions on tensile properties of AZ91D alloy products prepared by injection molding
    Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Seiichi Akazawa
    Keikinzoku/Journal of Japan Institute of Light Metals, Japan Institute of Light Metals, 64(9) 407 - 412, 2014, Scientific journal
  • Study on Patch Bonding for Recovery of Damaged Carbon Fiber Reinforced Thermoplastics by Four-Point Bending Method
    Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki; Rei Yamagishi; Masahiro Yamamoto
    Journal of Materials Science Research, 2(3) 60 - 67, Jun. 2013
  • An Estimation Method of Pixel Value Distributions in Consideration of Conservation of Energy
    YAMAUCHI Hitoshi; OZAKI Koichi; SATO Yoichiro; FUKUTA Tadao; OBUNAI Kiyotaka
    IEICE technical report. Image engineering, 一般社団法人電子情報通信学会, 113(20) 29 - 34, 26 Apr. 2013
  • Synthesization of CNT on Surface of C/C composites to Stabilize the Coefficient of Friction Through a Wide Environmental Temperature Range
    Kiyotaka Obunai; Kazuya Okubo; Toru Fujii
    Journal of Materials Science Research, 2(1) 15 - 22, Jan. 2013
  • Fundamental research of repair for bending damaged carbon fiber reinforced thermoplastics under bending load
    Masahiro Yamamoto; Rei Yamagishi; Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki
    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 79(802) 759 - 763, 2013, International conference proceedings
  • Development of Al-Mg-Zn casting alloy with brilliant for automotive wheels
    Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Shinsuke Ujihira; Kosuke Kitaura; Hideki Kanetsuki; Koji Murakami; Makoto Hino
    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 79(802) 838 - 846, 2013, International conference proceedings
  • Effect of finely dispersed cementite on tensile properties of tempering steel using super rapid induction heating
    Ryosuke Miyakoda; Yuki Yamamoto; Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki
    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 79(802) 754 - 758, 2013, International conference proceedings
  • 湯流れ解析と実成形品調査による欠陥発生率関数を用いた欠陥予測
    木村紀公; 小武内清貴; 福田忠生; 尾崎公一
    日本鋳造工学会中国四国支部会報こしき, (35) 30 - 33, Dec. 2012
  • Improvement of bending strength and fracture toughness of C/C composite by adding carbon particles with 3-dimensional web-like structures
    Kiyotaka Obunai; Kazuya Okubo; Toru Fujii
    Zairyo/Journal of the Society of Materials Science, Japan, 公益社団法人 日本材料学会, 61(5) 468 - 473, May 2012, Scientific journal
  • Tensile properties of S45C steel using super rapid induction tempering
    Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki; Takahiro Tanaka; Yuki Yamamoto
    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 一般社団法人 日本機械学会, 78(789) 632 - 636, 2012, International conference proceedings
  • Improvement of Mechanical Properties of C/C composite by Addition of Carbonized MFC into Carbon Precursor
    Obunai Kiyotaka; Takeuchi Yasunori; Okubo Kazuya; Fujii Toru
    The science and engineering review of Doshisha University, 同志社大学, 51(3) 26 - 31, Oct. 2010
  • Modification of strain distribution on contact surface of shoe to reduce low frequency squeals for brake disc with small holes
    Kiyotaka Obunai; Sho Hagiwara; Kazuya Okubo; Toru Fujii; Tsuyoshi Nakatsuji
    SAE Technical Papers, 2010, International conference proceedings
  • Brake Torque Variation on Wave Type Brake Disc for Motorcycles
    OBUNAI Kiyotaka; OKUBO Kazuya; FUJII Toru; NAKATSUJI Tsuyoshi
    Transactions of the Society of Automotive Engineers of Japan, 自動車技術会, 40(4) 961 - 966, 25 Jul. 2009
  • Characterization of brake torque variation of wave type brake disc for motorcycles
    Kiyotaka Obunai; Kazuya Okubo; Toru Fujii; Tsuyoshi Nakatsuji
    SAE Technical Papers, 2009, International conference proceedings
  • Brake Torque Variation on Wave Type Brake Disc for Motorcycles
    OBUNAI Kiyotaka; OKUBO Kazuya; FUJII Toru; NAKATSUJI Tsuyoshi
    Transactions of the Society of Automotive Engineers of Japan, 自動車技術会, 39(2) 63 - 66, 25 Mar. 2008
  • Study on low speed judder of wave type brake discs for motorcycles
    Kiyotaka Obunai; Kazuya Okubo; Toru Fujii; Tsuyoshi Nakatsuji
    SAE Technical Papers, SAE International, 13 Nov. 2006, International conference proceedings

MISC

  • セルロースナノファイバーを母材に予添加した一方向性CRFPの面外衝撃エネルギ吸収率の向上-予添加材の添加率の影響-
    宮谷和伸; 大窪 和也; 小武内 清貴; 峯村 淳; 小倉 孝太; 森本 裕輝
    Dec. 2024, Summary national conference
  • 構造化スーパキャパシタに用いるポリイミド粉末添加セルロース複合フィルムの電気抵抗及び引張強度に及ぼすセルロース種別の影響
    溝渕進也; 小武内清貴; 大窪和也
    Dec. 2024, Summary national conference
  • Energy absorption ratio of pre-addition of cellulose nanofibers into matrix of uni-directional CFRP under out of plane impact loading by drop weight
    Kazunobu MIYATANI; Kazuya OKUBO; Kiyotaka OBUNAI; Atsushi MINEMURA; Kota OGURA; Yuki MORIMOTO
    Nov. 2024, Summary international conference
  • ポリイミド粉末添加セルロースフィルムを代替基材とした構造化スーパキャパシタ複合材の電気抵抗および強度の変化
    溝渕進也; 小武内清貴; 大窪和也
    Nov. 2024, Summary national conference
  • 湾曲形状に成形した一方向炭素繊維強化複合材料の母材への微細ガラス繊維添加による曲げ衝撃特性の改善
    天谷 律希; 大窪 和也; 小武内 清貴
    Nov. 2024, Summary national conference
  • 同軸押出ノズルを用いて作製したガラス繊維/PLA/PETG積層平板の 衝撃吸収エネルギーに及ぼす内外送り比の時間的変化勾配の影響
    栁谷純輝; 小武内清貴; 大窪和也
    Nov. 2024, Summary national conference
  • ポリ乳酸を母材とした植物繊維複合材料の衝撃強度の温水浸漬による経時変化に及ぼす植物繊維種別の影響
    藤井雅志; 大窪和也; 小武内清貴
    Nov. 2024, Summary national conference
  • Changes of Shifting Rate of Metal V-belt Type CVT during Speed Up/Down under Quasi-Idle Loading Condition
    Yuichirou Mori; Kazuya Okubo; Kiyotaka Obunai
    Oct. 2024, Summary international conference
  • Improvement of Fatigue Life of Unidirectional Carbon Fiber Composite by Modification of Vinyl Ester Matrix with Rubber Particles under Cryogenic Condition
    Naofumi Terada; Kiyotaka Obunai; Kazuya Okubo; Yukiko Fujita
    Oct. 2024, Summary international conference
  • 一方向性炭素繊維強化複合材料の高温環境下での疲労寿命に及ぼすビニルエステル樹脂母材のゴム変性の影響
    増井悠希; 小武内清貴; 大窪和也; 藤田幸子
    Oct. 2024, Summary national conference
  • IMPROVEMENT OF STATIC STRENGTH AND FATIGUE DURABILITY OF BOLTED JOIINT OF WOVEN CARBON FIBER REINFORCED COMPOSITE PLATE BY INSERTING MAT OF PVA NANOFIBERS
    Seiya Watanabe; Kiyotaka Obunai; Kazuya Okubo
    Sep. 2024, Summary international conference
  • セルロースナノファイバーを母材に予添加した 一方向性CRFPの面外衝撃エネルギ吸収率
    宮谷 和伸; 小武内 清貴; 大窪 和也; 峯村 淳; 小倉 孝太; 森本 裕輝
    Sep. 2024, Summary national conference
  • Location of Noise Generation of Metal V-Belt Type Cvt Driven on Model Test Bench – Estimation by Beamforming Method –
    Yoshiyuki Ohashi; Kazuya Okubo; Kiyotaka Obunai
    Jun. 2024, Summary international conference
  • 金属Vベルト式CVTの無負荷時での増速および減速速度の変化要因
    森 裕一郎; 大窪 和也; 小武内 清貴
    May 2024, Summary national conference
  • 竹繊維をコアに持つポリ乳酸樹脂母材の3D プリンタ用造形材の引張特性
    栁谷純輝; 小武内清貴; 大窪和也
    Mar. 2024, Summary national conference
  • Change of Transmitting Properties of Rubber V-belt for CVT according to Difference of Stiffness
    TANAKA Kenichiro; OBUNAI Kiyotaka; OKUBO Kazuya; DOI Ikuhito; KATO Hideyuki
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 06_613 , 2020
  • An Method to Improve Fatigue Life of Fiber Reinforced Composite:- Introduction of Applications with Additions of Fine Fibers into Matrix -
    OKUBO Kazuya; OBUNAI Kiyotaka
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 03_kicyo , 2020
  • Stress relaxation of CFRP plate fastened by bolt in thickness direction:-Influence fastening torque, temperature condition and types of reinforcement-
    石田 貴大; 小武内 清貴; 大窪 和也; 佐々 喜紀; 石川 健
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 P_009 , 2020
  • Improvement of impact property of curved thin shell fabricated with chopped tape CFRP:- Influence of diameter of added submicron glass fiber into matrix -
    UEDA Taiki; OKUBO Kazuya; OBUNAI Kiyotaka; Li BAO
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 P_010 , 2020
  • Influence of impact energy on improvement rate of energy absorption of chopped carbon fiber reinforced FRP during drop impact test due to addition submicron glass fiber into matrix
    OKIMURA Takuma; OKUBO Kazuya; OBUNAI Kiyotaka
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 P_012 , 2020
  • Evaluation of interfacial shear strength between fiber and resin using Sprit Hopkinson Pressure Bar method
    村山 凌太郎; 小武内 清貴; 大窪 和也
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2020 P_007 , 2020
  • Design of Fixed-wing Multicopter Made from Carbon Fiber Composite Plate:-Suppression of Aeroelastic Effect in Wing Structure by Bending-Torsion Coupling Deformation-
    TERASAKI Kazuki; Obunai Kiyotaka; Okubo Kazuya
    The Proceedings of Design & Systems Conference, The Japan Society of Mechanical Engineers, 2020 1505 - 1505, 2020
  • Improvement of Inter-Laminar Strength and Mode I Inter-Laminar Fracture Toughness of Uni-Direction CFRTP Laminate by Ultrasonic Needle Punching
    西原伊央利; 小武内清貴; 金崎真人; 福田忠生; 尾崎公一
    第44回複合材料シンポジウム, Sep. 2019
  • Effect of Densification of SiC-C/C Composites Modified by Glass Fiber in Precursor Resin on Friction Properties
    高佳祐; 小武内清貴; 金崎真人; 福田忠生; 尾崎公一
    第44回複合材料シンポジウム, Sep. 2019
  • Measurement of Fracture Toughness by using CNRB specimen
    金崎真人; 小武内清貴; 福田忠生; 尾崎公一
    日本機械学会材料力学部門若手シンポジウム2019, Aug. 2019
  • Improvement of Interfacial Properties between Matrix and Carbon Fiber by Imparting Polarity to Plastic Matrix of CFRP
    MATSUDA Ryosuke; WATANABE Kenichi; OBUNAI Kiyotaka; OKUBO Kazuya
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2019 309 - 309, 2019
  • Prevention of interfacial strength reduction of CFRTP fabricated with MXnylon as matrix:-Investigation of molding atmosphere condition and temperature condition-
    ITAMI Akihito; OBUNAI Kiyotaka; OKUBO Kazuya; NISHIDA Hironori; TAKEI Hiroyuki
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2019 312 - 312, 2019
  • Improvement of fatigue life of metal-CFRTP bolted joint by using heat pressing before fatigue process.
    YOSHIKAWA Rikiya; OBUNAI Kiyotaka; OKUBO Kazuya
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2019 314 - 314, 2019
  • Improvement of fatigue life of plain woven CFRP by adding carbon milled fibers (CMFs) into polymer matrix:-its orientation control by applying magnetic field-
    Murayama Ryotaro; Obunai Kiyotaka; Okubo Kazuya
    The Proceedings of the Materials and Mechanics Conference, The Japan Society of Mechanical Engineers, 2019 OS0325 , 2019
  • 表面及び内部空孔にSiCを生成したC/C複合材料の摩擦係数の温度依存性の低減及び摩耗抑制
    若本昇; 小武内清貴; 大窪和也; 藤井透
    関西支部講演会講演論文集, 一般社団法人 日本機械学会, 2017.92(0), 2017
  • 高温環境下におけるSCM435の低サイクル疲労挙動
    川瀬皐士朗; 小武内清貴; 福田忠生; 尾崎公一
    中国四国支部総会・講演会 講演論文集, 一般社団法人 日本機械学会, 2017.55(0), 2017
  • 射出プランジャ型水モデル可視化装置を用いた金型内充填挙動の調査
    小野 貴大; 小武内 清貴; 福田 忠生; 尾崎 公一
    鋳造工学 全国講演大会講演概要集, 公益社団法人 日本鋳造工学会, 168(0) 53 - 53, 2016
  • ナノハイブリッドシートを用いた樹脂のレーザ接合に関する数値解析
    松本卓也; 尾崎公一; 福田忠生; 小武内清貴
    計算力学講演会講演論文集, 一般社団法人 日本機械学会, 2016.29(0), 2016
  • Fatigue and hydrogen embrittlement properties of Al-Mg-Zn series casting alloy with Cu addition
    Yudai Nasu; Tadao Fukuta; Kiyotaka Obunai; Koichi Ozaki
    72nd World Foundry Congress, WFC 2016, 365 - 366, 01 Jan. 2016
  • 080 Determination of dimension of circumferential notched round bar specimen for fracture toughness test
    TASAI Dairoku; FUKUTA Tadao; OBUNAI Kiyotaka; OZAKI Koichi
    The Computational Mechanics Conference, The Japan Society of Mechanical Engineers, 2015(28) "080 - 1"-"080-2", 10 Oct. 2015
  • An estimation method of pixel value distributions in consideration of conservation of energy
    Hitoshi Yamauchi; Koichi Ozaki; Yoichiro Sato; Tadao Fukuta; Kiyotaka Obunai
    IEEJ Transactions on Electronics, Information and Systems, Institute of Electrical Engineers of Japan, 135(5) 545 - 552, 01 May 2015
  • A Projection Transformation Method in Consideration of Conservation of Energy
    YAMAUCHI Hitoshi; OZAKI Koichi; SATO Yoichiro; FUKUDA Tadao; OBUNAI Kiyotaka
    IEICE technical report. Image engineering, The Institute of Electronics, Information and Communication Engineers, 114(460) 137 - 142, 23 Feb. 2015
  • G0310701 Effect of Microstructure on Strength Properties under Corrosive Environment of Al-Mg-Zn Series Alloy
    TANABE Akihiro; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2014 "G0310701 - 1"-"G0310701-5", 07 Sep. 2014
  • G0110105 Determination of Defect Occurrence Function of Injection Molded Magnesium Alloy Products by Numerical Simulation
    AKIYAMA Ryohei; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2014 "G0110105 - 1"-"G0110105-5", 07 Sep. 2014
  • OS1728 Moderation of Dependence of Frictional Coefficient of C/C Composite on Temperature due to Addition of Glass Fibers into Carbon Precursor
    FUJITANI Ryohei; OBUNAI Kiyotaka; OKUBO Kazuya; FUJII Toru
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2014 "OS1728 - 1"-"OS1728-3", 19 Jul. 2014
  • 第一原理計算に基づくAl-Mg-Zn系合金結晶粒界の水素脆化特性評価
    福田忠生; 小武内清貴; 尾崎公一; 北浦宏将; 田辺晃弘
    光アライアンス, 25(4) 36 - 39, Apr. 2014, Introduction commerce magazine
  • Proposing of Image Interpolation Method Considering Conservation of Brightness Energy and Its Application for Digital Image Measurement
    原 卓土; 小武内 清貴; 福田 忠生
    日本実験力学会講演論文集, 日本実験力学会, (14) 147 - 150, 2014
  • Evaluation of Fracture Toughness by using Circumferentially Notched Small Round bar
    太才 大陸; 福田 忠生; 小武内 清貴
    日本実験力学会講演論文集, 日本実験力学会, (14) 307 - 310, 2014
  • GS11 Tensile Characteristics of Al-Mg-Zn series Alloy in Corrosive
    KITAURA Kosuke; TANABE Akihiro; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koiti
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2013 "GS11 - 1"-"GS11-2", 12 Oct. 2013
  • GS45 Plane Strain Fracture Toughness Test Used Small Round Bar Specimen with Circumferential Notch
    MIYAKODA Ryosuke; FUKUTA Tadao; OBUNAI Kiyotaka; OZAKI Koichi
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2013 "GS45 - 1"-"GS45-3", 12 Oct. 2013
  • A Linear Transformation method in Consideration of Conservation of Energy
    YAMAUCHI Hitoshi; OZAKI Koichi; SATO Yoichiro; FUKUTA Tadao; OBUNAI Kiyotaka
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, The Institute of Electronics, Information and Communication Engineers, 113(212) 91 - 96, 12 Sep. 2013
  • A Linear Transformation method in Consideration of Conservation of Energy
    YAMAUCHI Hitoshi; OZAKI Koichi; SATO Yoichiro; FUKUTA Tadao; OBUNAI Kiyotaka
    IEICE technical report. Life intelligence and office information systems, The Institute of Electronics, Information and Communication Engineers, 113(210) 91 - 96, 12 Sep. 2013
  • A Linear Transformation method in Consideration of Conservation of Energy
    YAMAUCHI Hitoshi; OZAKI Koichi; SATO Yoichiro; FUKUTA Tadao; OBUNAI Kiyotaka
    IEICE technical report. Image engineering, The Institute of Electronics, Information and Communication Engineers, 113(211) 91 - 96, 12 Sep. 2013
  • G031023 Relations between Constant Tensile Characteristics under Corrosive Environment and Zn Contents in Al-Mg-Zn Series Alloy
    TANABE Akihiro; KITAURA Kosuke; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2013 "G031023 - 1"-"G031023-4", 08 Sep. 2013
  • G011033 Prediction of casting defect in Mg alloy castings by using of numerical simulations
    KIMURA Norimasa; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2013 "G011033 - 1"-"G011033-5", 08 Sep. 2013
  • G031034 Proposing of Newly Image Interpolation and Its Application for Digital Image Measurement
    HARA Takuto; TSUTSUI Masato; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2013 "G031034 - 1"-"G031034-4", 08 Sep. 2013
  • G031013 Improvement on Bending Strength of Injection Molded AZ91D by Addition of Carbon Black
    AKAZAWA Seiichi; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2013 "G031013 - 1"-"G031013-5", 08 Sep. 2013
  • 203 Prediction of casting defect by using of numerical simulations
    KIMURA Norimasa; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    講演論文集, The Japan Society of Mechanical Engineers, 2013(51) "203 - 1"-"203-2", 25 Feb. 2013
  • 211 Development of non-contact optical measurement system by time-series camera image
    TSUTSUI Masato; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    講演論文集, The Japan Society of Mechanical Engineers, 2013(51) "211 - 1"-"211-2", 25 Feb. 2013
  • Study on patch bonding for recovery of damaged CFRTP under bending load
    Rei Yamagishi; Kiyotaka Obunai; Tadao Fukuta; Koichi Ozaki
    8th Asian-Australasian Conference on Composite Materials 2012, ACCM 2012 - Composites: Enabling Tomorrow's Industry Today, 2 1204 - 1209, 01 Dec. 2012
  • GS45 Repair of CF/PA6 composites with bending failure
    YAMAMOTO Masahiro; YAMAGISHI Rei; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2012 "GS45 - 1"-"GS45-3", 22 Sep. 2012
  • GS15 Tensile Properties and Effect for dispersed finely cementite of QT steel using Super Rapid Induction Tempering
    MIYAKODA Ryosuke; YAMAMOTO Yuki; FUKUTA Tadao; OBUNAI Kiyotaka; OZAKI Koichi
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2012 "GS15 - 1"-"GS15-3", 22 Sep. 2012
  • G030081 Hydrogen embrittlement characteristics of heat treated Al-Mg-Zn series alloy
    KITAURA Kosuke; UJIHIRA Shinsuke; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2012 "G030081 - 1"-"G030081-3", 09 Sep. 2012
  • G040022 Endurance Evaluation of BTDP
    ITO Hiromasa; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi; OKAMOTO Takemitu; ONISHI Kenji; IOGAWA Yoshihiro
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2012 "G040022 - 1"-"G040022-4", 09 Sep. 2012
  • G030026 Investigation of tensile properties evaluated by small type specimen
    YAMAMOTO Yuki; TSUTSUI Masato; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2012 "G030026 - 1"-"G030026-4", 09 Sep. 2012
  • 817 A study of tensile properties using small specimen
    YAMAMOTO Yuuki; TANAKA Takahiro; Fukuta Tadao; OBUNAI Kiyotaka; OZAKI Kouichi
    関西支部講演会講演論文集, The Japan Society of Mechanical Engineers, 2012(87) "8 - 17", 16 Mar. 2012
  • 307 Characteristic evaluation of fiber reinforced rubber for BTDP
    ITO Hiromasa; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    講演論文集, The Japan Society of Mechanical Engineers, 2012(50) 30701 - 30702, 28 Feb. 2012
  • 105 Tensile Properties of Super Rapid Induction Tempering Steel
    TANAKA Takahiro; YAMAMOTO Yuki; FUKUTA Tadao; OBUNAI Kiyotaka; OZAKI Koichi
    講演論文集, The Japan Society of Mechanical Engineers, 2012(50) 10501 - 10502, 28 Feb. 2012
  • 306 Development of Al-Mg-Zn Alloy with brilliant for Automotive wheel use
    UJIHIRA Shinsuke; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi; HINO Makoto; MURAKAMI Koji
    学術講演会講演論文集, 日本材料学会, 61 67 - 68, 2012
  • 309 Improvement for Strength of Injection Molded AZ91D by Addition of Graphite Powder
    SUZUKI Masaki; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Kouichi
    学術講演会講演論文集, 日本材料学会, 61 73 - 74, 2012
  • 611 Fundamental study on repair of bending damaged carbon fiber reinforced thermoplastics
    YAMAGISHI Rei; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    学術講演会講演論文集, 日本材料学会, 61 157 - 158, 2012
  • 208 Simulation of Laser Joining of Plastic Plates with Nano-Hybrid Sheet
    OZAKI Koichi; FUKUTA Tadao; OBUNAI Kiyotaka
    The Computational Mechanics Conference, The Japan Society of Mechanical Engineers, 2011(24) 34 - 35, 08 Oct. 2011
  • 2312 Study on Injection Molding of Mg Alloy Defects Prediction used Simulation
    KANZAKI Taiyo; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    The Computational Mechanics Conference, The Japan Society of Mechanical Engineers, 2011(24) 655 - 656, 08 Oct. 2011
  • G040062 Influence of Mold Temperature on Fluidity Length of ADC12
    SUZUKAWA Masahiro; UJIHIRA Shinsuke; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2011 "G040062 - 1"-"G040062-3", 11 Sep. 2011
  • G040061 Strength Property of Carbon-doped AZ91D Products made by lnjection Molding
    KAMAKURA Hiroyuki; SUZUKI Masaki; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    Mechanical Engineering Congress, Japan, The Japan Society of Mechanical Engineers, 2011 "G040061 - 1"-"G040061-4", 11 Sep. 2011
  • GS06 Tensile Properties of Super Rapid Induction Tempering Steel
    TANAKA Takahiro; YAMAMOTO Yuki; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2011 "GS06 - 1"-"GS06-3", 16 Jul. 2011
  • GS09 Influence of Natural aging of Al-Mg-Zn series alminium alloy
    FUJIWARA Takuya; UJIHIRA Shinsuke; OBUNAI Kiyotaka; FUKUTA Tadao; OZAKI Koichi
    M&M材料力学カンファレンス, The Japan Society of Mechanical Engineers, 2011 "GS09 - 1"-"GS09-3", 16 Jul. 2011
  • 424 Improvement of Coefficient of Friction between C/C Composites
    OBUNAI Kiyotaka; OKUBO Kazuya; FUJII Toru
    The Proceedings of Conference of Kansai Branch, The Japan Society of Mechanical Engineers, 2011(0) _4 - 24_, 2011
  • Synthesization of CNT on surface of C/C composites by alcohol CVD method and its effect on coefficient of friction between them
    K. Obunai; K. Okubo; T. Fujii
    25th Technical Conference of the American Society for Composites and 14th US-Japan Conference on Composite Materials 2010, 1 711 - 720, 01 Dec. 2010
  • G04002-5 Improvement of mechanical properties of carbon fiber reinforced carbon composites by addition of Carbonized MFC into carbon precursor
    TAKEUCHI Yasunori; OBUNAI Kiyotaka; OKUBO Kazuya; FUJII Toru; NAKATSUJI Tsuyshi
    The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2010(0) 363 - 364, 2010

Industrial Property Rights

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  • Patent right
    炭素繊維強化炭素複合材料及びその製造方法
    仲辻 毅, 藤井 透, 大窪 和也, 小武内 清貴, 竹内 康徳
    特願2009-194259, 特開2011-046543, サンスター技研株式会社, 学校法人同志社
  • Patent right
    外周波型ブレーキディスク
    星 良雄, 仲辻 毅, 藤井 透, 大窪 和也, 小武内 清貴
    JP2008050571, WO2008-090809, サンスター技研株式会社

Research Projects

  • Study on mechanical characteristics of nano- micro-fiber under various strain speed conditions
    小武内 清貴; 大窪 和也
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, 2024/04 -2027/03, Grant-in-Aid for Scientific Research (C), Doshisha University
  • Investigation and improvement of interfacial strength between fiber and matrix under impact loading
    小武内 清貴; 大窪 和也
    本年度は,引張型SHPB装置および計装式振子型衝撃試験機を用い,異なるひずみ速度下における強化繊維-母材樹脂間の界面せん断強度および一方向複合材料の衝撃吸収エネルギの評価方法を確立した.確立した評価方法を用い,炭素繊維/エポキシ系およびガラス繊維/エポキシ系の界面せん断強度を調査したところ,ガラス繊維/エポキシ系においては,ひずみ速度の増加に伴って,両者の界面せん断強度は増加したが,炭素繊維/エポキシ系においては,両者の界面せん断強度は,ひずみ速度の増加に伴って低下した.これは一方向複合材料の衝撃エネルギにおいても同様となった.また,母材エポキシ樹脂をサブミクロンガラス繊維によって改質した場合,炭素繊維/エポキシ系において,高ひずみ速度条件下での界面せん断強度,ならびに一方向複合材料の衝撃吸収エネルギが増加した. これは,母材に添加した高ひずみ速度下において,サブミクロンガラス繊維と母材との間に剥離が生じ,母材中の弾性波の進展を阻害したためと考えられる.現在は,より詳細にサブミクロンガラス繊維添加の効果を調査中である. また,炭素繊維において,その表面改質(サイジング処理)が,炭素繊維/エポキシ樹脂間の界面せん断強度におよぼす影響を,異なるひずみ速度下で調査したところ,現在一般に使用されているサイジング処理による界面せん断強度向上効果は,ひずみ速度の増加に伴って減衰することを見出した.この繊維表面処理の効果については,より詳細な調査を,来年度に向けて実施予定である., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), 2021/04 -2024/03, Grant-in-Aid for Scientific Research (C), Doshisha University
  • Formulation of design criteria and improvement of durability of carbon fiber reinforced composite joint subjected to in-plane and out of plane loading.
    大窪 和也; 小武内 清貴
    本研究では,平板を用いた2次元的に単純な継手構造だけではなく,CFRP(炭素繊維強化プラスチックス)を用いた実用的に広範囲な種別の接合構造を想定し,その全般を含むような接合構造の強度設計手法と設計規準を社会に提唱すると共に,長期使用に対する疲労耐久性を高めるための新技術を社会に提供し当該の学術・産業分野に貢献する事を目的として研究を開始した.この初年度においては,研究開始の前年度まで行って来た研究課題(「ボルト締結した炭素繊維強化複合材料の耐久性の改善と設計規準の確立」:基盤研究(C),課題番号:15K06471)を発展させ,bite plate(ダイス状の突起をその表面に有する金属板)を利用する手法を応用し,その疲労耐久性の改善検証を行った.疲労耐久性試験では実用条件を考え,負荷形式をボルトに対する引張せん断式とし,ボルトサイズを汎用のM6,締結トルクを汎用的な10Nmとした.実験では母材をPP,強化材をCF(Carbon Fiber:炭素繊維)とする直交積層CFRTP板を被締結材とし,これにマイクロミリメータサイズの微細ガラス繊維やPP製フィルムを併用する継手構造を疑似的に再現した. 研究の結果,ボルト穴近傍での初期損傷の存在を仮定し,疲労耐久性寿命の指標となる臨界エネルギ解放率の変化をコンプライアンス法により測定したところ,臨界エネルギ解放率と継手効率との間には正の相関関係が存在することを確認した.また疲労進展状態の違いを詳細に把握し,Bite plateと改質フィルムを併用すると,き裂進展面付近での炭素繊維上の樹脂の残存量が多くまたは覆われた状態を維持できる事を明らかにした.また適切な条件でBite plateを溶融併用すると,Bite plateを適用した領域内での局所的な炭素繊維と樹脂の接着性が改善され,疲労き裂の進展抑制に寄与する事も明らかにした., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), 2019/04 -2023/03, Grant-in-Aid for Scientific Research (B), Doshisha University
  • Improvement in mechanical properties and fatigue life of CFRTP due to an addition of sub-micron glass fibers and their mechanisms
    Fujii Toru
    First, the effect of submicron glass fiber (sGF) addition to the VE matrix of C-SMC having various chopped carbon fibers was investigated. However, except for the impact strength, stable performance improvement of mechanical characteristics including fatigue life was not obtained due to sGF addition. High molecular weight thermos-plastic epoxy (TP-EP) having almost the same basic molecular structure as the thermosetting epoxy (TS-EP), CFRTP whose mechanical performance is comparable to TS-EP CFRP was obtained. The key to the performance of this material is the adhesive strength in CF/EP interface. We have developed a FRTP unidirectional tape with 3% sGF added to PP and a laminated board using this tape. In CFPP, the addition of sGF significantly improves impact resistance. The hemispherical molded product can bring out its maximum characteristics. CFTP using TP-EP significantly improved the CAI strength. This is due to an introduction of many fracture origins by sGF., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), 2018/04 -2021/03, Grant-in-Aid for Scientific Research (B), Doshisha University
  • 木質・草木バイオマス資源を主とする熱硬化性成形原料の創生
    小武内 清貴
    産学が連携した研究開発成果の展開 研究成果展開事業 マッチングプランナープログラム, 2015 -2016, 岡山県立大学
  • Inter-laminar fracture toughness enhancement of CFRTP by using super-sonic needle punching
    OBUNAI Kiyotaka
    This study proposes an effective technique to improve the inter-laminar property of CFRTP. In this study, CFRTP in which matrix was made of PA6 was fabricated. The fabricated CFRTP was cut into strip specimen. The fabricated specimen was super-sonic needle punching with designated condition. The super-sonic needle punch technique was employed to specimen and its effect of inter-laminar property was characterized under four-point bending and Mode I load. Test results showed that the higher bending strength was obtained by super-sonic needle punching specimen compared to that of hot needle punched specimen. DCB test results also showed that the critical load and fracture toughness at initial crack propagation was improved by super-sonic needle punching. These results revealed that the super-sonic needle punching was effective to improve Mode I inter-laminar fracture toughness of CFRTP without degradation of bending characteristics., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), 2013/04 -2015/03, Grant-in-Aid for Young Scientists (B), Okayama Prefectural University
  • Proposing of repair method of CFRTP by needle punching and patchbonding
    OBUNAI Kiyotaka
    The purpose of this study is to investigate the fracture morphology and repairbility of CFRTP. Four-point bending test was conducted to investigate the fracture morphology of CFRTP subjected to bending load. Test results showed that the local delamination was first appeared when the 2.0% of bending strain was applied. When the 2.5% of bending strain was applied, the damage of fiber due to the local buckling was observed at compression side of specimen. The effect of patch bonding on bending strength and modulus was also evaluated. Test results showed that damaged specimen would be repaired when appropriate layer of patch was bonded, and the patch bonding at compression side was more effective than that at tension side. The effect of needle punch on bending characteristics of CFRTP was also evaluated. Test results showed that the interlaminar strength of CFRTP was improved due to the delamination was supressed by needle punch. Moreover , bending strength and modulus of CFRTP repaired by needle punching and patch bonding was higher than that repaired by only patch bonding., Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up, 2011 -2012, Grant-in-Aid for Research Activity Start-up, Okayama Prefectural University
  • MFCの微細3D構造によるブレーキディスク用C/C複合材料の高性能,高機能化
    小武内 清貴
    本研究テーマでは,微細な3D構造を有する炭化MFCの添加がC/C複合材料の強度特性に与える影響を詳細に調査した.その結果,炭化MFCを適量(1wt%)添加することによって,1方向C/C複合材料の曲げ強度が大きく改善することがわかった.この改善は炭化MFCによって炭素マトリクスの強度およびじん性の向上によるものであることがわかった.また,針状の微細繊維や球状の黒鉛等,異なる形状の添加材を用いて調査したところ,強度改善効果があるのは微細な3D構造を有する炭化MFCのみとなった.これらのことから,微細な3D構造によって,C/C複合材料焼成時に発生する空孔の形状が微細化され,その結果強度改善につながったと考えられる.本成果を応用することによって,多くのコストおよびエネルギを要する緻密化工程を省略することが可能となり,C/C複合材料の低価格化が可能となる. また本研究テーマでは,内部に空孔を有するC/C複合材料を対象とし,その空孔内部にCNTを生成し,摩擦特性を改善する手法を開発した.緻密化を省略し,内部に空孔を有するC/C複合材料を作製し,その空孔に熱CVD法によってCNTを生成した.CNTを生成したC/C複合材料は,従来のC/C複合材料に比べ,摩耗特性に大きな影響を与えることなく,摩擦係数の温度依存性が解消されることがわかった.この効果は,摺動面に生成されたCNTがC/C複合材料に対して硬く,アブレシブ摩耗を発生させていることがわかった.このアブレシブ摩耗はナノオーダで発生しているため,マクロな摩耗特性に大きな影響を与えないことが分かった.また摩耗しても摺動面に周期的にCNTが露出することによって,永続的な改善効果が期待できることもわかった.本成果を応用することによって,軽量かつ高摩擦係数を有する一般車両用C/C複合材料性の摩擦材開発が可能である., 日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 2010 -2011, 特別研究員奨励費, 同志社大学

Social Contribution

  • 同志社大学サイエンスアカデミー2021, 京田辺市, 同志社大学サイエンスアカデミー2021, 2021/08/13, Visiting lecture
  • 同志社大学サイエンスアカデミー2019, 京田辺市, 同志社大学サイエンスアカデミー2019, 2019/07/26, Visiting lecture