Kyushu University Academic Staff Educational and Research Activities Database
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Ren Kadowaki Last modified date:2018.05.14

Academic Degree
Ph.D. in Engineering
Country of degree conferring institution (Overseas)
Field of Specialization
Total Priod of education and research career in the foreign country
Research Interests
  • Study on non-destructive evaluation by detecting ultrasonic instantaneous frequency
    keyword : Ultrasonic, Non-destructive evaluation, Instantaneous Frequency, Wavelet transform, Minute abnormality, Crack, delamination
  • Mode grouping technique for an efficient design of an automobile body
    keyword : Vibration analysis, Characteristic mode, Mode grouping, Finite element method, Vibration control
  • Study on a vibration system automatically following to excitation frequency
    keyword : Natural Frequency, Forced Vibration, Dynamic Damper, Nonlinear Vibration
Academic Activities
1. Ren Kadowaki, Hitoshi Kimura, Norio Inou, New Estimation Methods of Young's Modulus and Rupture Strength of Snack Foods Based on Microstructure, Journal of Texture Studies,, 47, 1, 3-13, 2016.02, This paper describes quantitative methods for measuring substantial values of rupture strength and Young's modulus considering the inner, crispy snack food structure at the microscale. The samples used are crispy snack food. A conventional mechanical food test was conducted on a large sample size (>100 mm3), and only the apparent, macroscopic mechanical property of the food was measured without considering the microscopic structure. The proposed method integrates a small load compression test and finite element analysis for a test piece <10 mm3. Structural deformability of the test piece is calculated using finite element analysis. The estimated rupture strength of commercially available snack food ranged between 95 and 560 MPa. The calculated Young's moduli were in the range of 170-1,100 MPa. These values are 18-170 times larger than the apparent Young's moduli measured with the conventional method. This paper discusses the reasons for these findings..
1. Ren Kadowaki, Naoki Otsubo, Takumi Inoue, Kazuhisa Omura, Liquid Viscosity Evaluation using Ultrasonic Pulse, The 17th Asian Pacific Vibration Conference, 2017.10, The purpose of this study is development of a new viscosity evaluation method. We focus on ultrasonic pulse that is transmitted in the target liquid. The liquid viscosity is evaluated through attenuation of the ultrasonic pulse. As the first step, we tried to evaluate the viscosity of some types of mineral oil, whose viscosity were already known. We observed the two pulses that were transmitted in the mineral oil in a test container as shown in figure 1. Comparing the two reflected pulses in frequency domain, spectra of the attenuation in the oil were obtained. To calculate the viscosity of the oil, the theoretical relationships between the viscosity and the attenuation was essential. We performed a numerical simulation of pulse propagation with a lumped mass model as shown in figure 2. The relationships between the damping coefficients and the attenuation were elucidated from this numerical simulation. The damping coefficients were identified for the simulated pulse to resemble the experimental results in their attenuation. In the results, the oil viscosity that was over 100 mPas was evaluated using the experimental and theoretical results..
2. New testing method for viscosity of packaged liquids with ultrasonic pulse.
3. Three dimensional study of ultrasonic transmission in diagnosis of bolt loosening based on instantaneous frequency of the ultrasonic wave.
4. Ren Kadowaki, Takumi Inoue, Tatsuya Oda, Takahiro Nakano, New evaluation technique of seal strength of heat sealing with ultrasonic pulse, The 16th Asia Pacific Vibration Conference, 2015.11.
Membership in Academic Society
  • The Japan Society of Mechanical Engineers
  • Japanese Society for Mastication Science and Health Promotion
  • Japan Society for Food Engineering
  • Japan Ergonomics Society
  • The Robotics Society of Japan
  • Society of Biomechanisms Japan