■Faculty | Department of Human Factors Engineering and Environmental Design / Graduate School of Biology-Oriented Science and Technology |

■Position | Professor |

■Degree | |

■Commentator Guide | https://www.kindai.ac.jp/meikan/419-nishigaki-tsutomu.html |

■URL | |

Last Updated :2020/11/25

- 2018 , - 現在, Faculty of Biology-Oriented Science and Technology, Kindai University
- 2011 , - 2018 , Faculty of Biology-Oriented Science and Technology, Kindai University

- Informatics, Mechanics and mechatronics

- Effectiveness of a Rubber Band for Improving Usability of a Smartphone, Noriyasu Hirokawa, Yuki Sasaki, Yuki Tsumura, Tsutomu Nishigaki, Mitsushi Ohmasa, Jun. 2017 , Refereed
- Vibration Analysis of Rectangular Plates with Piezoelectric Film Actuators, Tsutomu Nishigaki, Izumi Umakoshi, Proceedings of MOVIC2014, Proceedings of MOVIC2014, Aug. 2014 , Refereed
- Measurement of piezoelectric properties of hydroxyapatite thin films fabricated by pulsed laser deposition method, NISHIGAKI TSUTOMU, NISHIKAWA HIROAKI, KUSUNOKI MASANOBU, HASHIMOTO YOSHIYA, HONTSU SHIGEKI, バイオインテグレーション学会誌, バイオインテグレーション学会誌, 3(1), 71 - 74, Sep. 2013 , Refereed
- Active vibration control using noncollocated piezoelectric film sensor/actuator, NISHIGAKI TSUTOMU, Proc SPIE, Proc SPIE, 7977(Pt.2), 79772L.1-79772L.6, 2011
- Self-sensing Vibration Control of a Fexible Beam Using Multilayered Shaped PVDF Films, Tsutomu Nishigaki, Proceedings of JISSE-11, Proceedings of JISSE-11, Oct. 2009 , Refereed
- Vibration control of a flexible beam with shaped piezoelectnc films, NISHIGAKI TSUTOMU, Proc SPIE, Proc SPIE, 7292(Pt.2), 72922H.1-72922H.12, 2009
- Several topics from active vibration control technique using piezoelectric films, NISHIGAKI TSUTOMU, Proc SPIE, Proc SPIE, 6928, 69281Z.1-69281Z.10, 2008
- Active control of railway wheel/rail noises by on-vehicle-type devices, Endo Mitsuru, Yaoita Akira, Maeda Natsuko, Nishigaki Tsutomu, The Journal of the Acoustical Society of Japan, The Journal of the Acoustical Society of Japan, 61(12), 698 - 707, Dec. 01 2005 Summary:本論文では, 鉄道車輪/レール系騒音のうちレールから放射される転動音の低減手法として, 移動する車上に設置したデバイスによるアクティブ騒音制御法を提案し, その可能性についての検討を行った。まず, 車体の下部開放部からの放射音を下流側全域で静音化することが原理的に可能な手法として, 波動吸収原理に基づく制御コンセプトを提案し, 境界要素法による音響シミュレーションによりコンセプトの妥当性を示した。また, デバイスユニットのプロトタイプ1基を設計・作製し, 実験室レベルでの騒音制御実験を実施した。実験は, 騒音源としてスピーカからのランダムノイズとレールのランダム加振音の両方を用いて行い, 実際に騒音制御効果が得られることを確認し, 開発したデバイスの有効性を実証した。
- Development of a Self-Sensing Actuator with Laminated Piezoelectric Films : Toward the Smart Vibration Control of Two-Dimensional Structures, NISHIGAKI Tsutomu, MORITA Hidenori, ENDO Mitsuru, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 69(680), 874 - 881, Apr. 25 2003 Summary:A self-sensing actuator constructed by four laminated piezoelectric films is developed toward the smart vibration control of two-dimensional structures. First, three kinds of mechanisms of self-sensing acutuators with two or four laminated piezoelectric films are proposed by examining the combinations of film construction and bridge circuits of analog electric controllers. And those self-sensing actuators are applied to the free vibration control of the first mode of a cantilever beam and it is ascertained that the vibration suppression effects are obtained by all the three mechanisms and the theories show good agreements with the experiments. Finally, the mechanism constructed by four laminated piezoelectric films is applied to the vibration control of a simply-supported rectangular plate as an example of two-dimensional structures and it is verified that the vibration control effect is actually obtained and the theory agrees well with the experiment.
- Analysis Method of the Nonstationary Response of Acoustical-Structural Coupling Systems, ENDO Mitsuru, NISHIGAKI Tsutomu, TOKIZAKI Tomoyuki, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 68(676), 3574 - 3581, Dec. 25 2002 Summary:This paper presents the numerical analysis method of the nonstationary response of acoustical-structural coupling systems. The acoustical analysis is formulated by the Boundary Element Method based on the hyper-singular boundary integral equation in order to deal with very thin elastic structures in the open space. The structural analysis is formulated by the Finite Element Method using the triangular thin plate element. Those fundamental equations are coupled by using the force equilibrium and the flux continuity conditions in the Laplace transformed domain, and the time history of nonstationary responses are obtained by the numerical inverse Laplace transform. The validity of the proposed method is examined in comparison with an analytical result and besides by conducting the experiments of nonstationary excitation of thin plates installed in the rectangular acoustic tube which is excited by a sinusoidal sound pressure from the planewave-driving type speaker. Finally, a few numerical calculation examples are shown. Those analyses treat the flexible I-shaped and L-shaped acoustic tubes which are excited by the sinusoidal pressure generated at the one end of acoustic tubes, and air medium displacements and sound pressures traveling in the tube and transmitted to the out of tubes are visually shown.
- Sound Decreasing Effects of Sound Absorbing Material Structures on the Vibrating Rigid Surface, ENDO Mitsuru, NISHIGAKI Tsutomu, KURAYA Tatsunori, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 68(670), 1663 - 1670, Jun. 25 2002 Summary:It was investigated experimentally whether the sound decreasing effects of sound absorbing material structures on the sinusoidally vibrating rigid surface are obtained or not. In the experiment, the one-dimensional acoustic tube was used and its one end is excited by the sound absorbing material structure and the other end is closed by glass wool. The experiments showed that almost 70% sound pressure decreasing effect is obtained at the maximum in the frequency range of 1〜3 kHz for the hard porous or fiber aluminum sound absorbing materials with the back air space made by using honeycomb structures. And it is observed that the frequency dependency of this decreasing effects is qualitatively and almost quantitatively coincident with the square root of reflectivity of the stationary absorbing material structure. But, for the urethane foam, this tendency could not be observed. It is supposed to be the flexible vibrational characteristics of urethane foam.
- Systematic Examinations of Vibration Suppression Effects of Dynamic Vibration Absorber Depending on the Design Criteria and Excitation Forms, ENDO Mitsuru, NISHIGAKI Tsutomu, NAKASU Yoshihiro, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 67(664), 3779 - 3786, Dec. 25 2001 Summary:As an example of passive vibration control devices, the dynamic vibration absorber installed in the main system of no-damping is considered and the vibration suppression effects for free vibration responses and forced steady-state and nonstationary responses are systematically examined as to the cases in which the device is designed according to the four typical design criteria, i.e., the conventional frequency shaped response function method (FPT), the linear quadratic optimal control theory (LQC), the minimum variance criterion (MVC) and the eigenvalue optimization criterion (EOC). As a result, the device designed by FPT, LQC and MVC shows almost equivalent vibration suppression effects and has a fairly good robustness, whereas EOC shows the worst effects of all except the settling time of free vibration. As another result, the frequency response evaluation method widely used as the criteria, for example, of transmission loss of noise insulating wall, transmission coefficient of silencer or H_∞ control theory turned out to be not necessarily valid especially for the nonstationary excitations.
- An Examination of Cross-sectional Configurations of Rail for Reduction of Rolling Noise of High-speed Railway, Mitsuru Endo, Tsutomu Nishigaki, Kou Mizuno, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 67(661), 2937 - 2944, 2001 Summary:Cross-sectional configurations of rail for reduction of rolling noise of high-speed railway Shinkansen are examined. First, depending on the Timoshenko's beam theory, the random vibration of an infinite rail with various cross sections subjected to the surface roughness excitation is analyzed considering the coupling with one material particle which is the model of wheel traveling on it. Then, the distributions of sound pressures radiated from those vibrating rails on the slab track are calculated based on the Boundary Element Method. In order to evaluate the reduction effects of rolling noise, the line spectrum approximation is introduced, and the radiated sound powers are estimated for seven definite frequencies in the range from 500 Hz to 2 000 Hz and relative reduction effects in comparison with the standard 60 kg long rail of the present Shinkansen are examined, and the effective rail cross-sectional configurations for reduction of rolling noise are proposed from the viewpoint of acoustic engineering. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.
- Proposition of a Self-Sensing Actuator Using Piezoelectric Films with Different Thickness (1st Report, Simplification of Hardware Aspects of Devices Toward the Realization of Smart Structures), Tsutomu Nishigaki, Atsushi Kawano, Mitsuru Endo, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 67(655), 612 - 619, 2001 Summary:A self-sensing actuator using piezoelectric two films with different thickness and area, which are closely installed on one surface of general curved structures and are treated as two capacitors in the active RC bridge circuit, is proposed from the view-point of simplification of hardware aspects of devices toward the realization of smart structures. It is first implied that this device is effective in the following points, i.e., 1) compensation of ME noises, 2) ability of obtaining high gain feedback and enough control power and 3) compensation of temprature for pyroelectric effect. Then, vibration control effects are estimated by theoretical analyses of free vibration response and harmonic steady-state response of a cantilever which is an example of fundamental flexible structures, and the guideline for constructing control circuit is shown. Finally, the validity of proposed self-sensing actuator scheme is verified by conducting the experiment of free vibration response of a cantilever. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.
- Proposition of a Self Sensing Actuator Using Piezoelectric Films with Different Thickness (2nd Report, Application to the Vibration Control of a Circular Ring), Tsutomu Nishigaki, Atsushi Kawano, Mitsuru Endo, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 67(655), 620 - 625, 2001 Summary:In the authors’ 1st report, a smart and simplified self-sensing actuator technique using piezoelectric films with different thickness is proposed. In this paper, application of the proposed method to the vibration control of curved structures is investigated. A flexible circular ring is treated as an example of curved structures and piezoelectric films with different thickness are bonded on one surface of the ring. The two films are treated as two capacitors in the active RC bridge circuit, and these are totally used as a self-sensing actuator. At first, fundamental equations of the circular ring with proposed self-sensing actuator are derived and vibration control effects are estimated by numerical analysis. Then, vibration control experiment is performed using an aluminum circular ring, and it is shown that the lowest vibration mode is efficiently controlled. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.
- A Self-sensing Actuator Using Piezoelecric Films with Different Thickness for Vibration Control of Curved Structures, Tsutomu Nishigaki, Mitsuru Endo, Procdeedings of 11th ICAST, Procdeedings of 11th ICAST, 200 - 207, Oct. 2000 , Refereed
- Evaluation of Vibrational Characteristics of Laminated FRP Circular Cylindrical Shells Including Damping Effect, Mitsuru Endo, Tsutomu Nishigaki, Takahisa Uesugi, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(647), 2143 - 2150, 2000 Summary:Evaluation method of vibrational characteristics of laminated FRP shells including damping is examined. Natural frequencies and loss factors of FRP circular cylindrical shells subjected to three kinds of prestresses are obtained on the ground of the first-order shear deformation shell theory by applying the modified Galerkin method. The results show that natural frequencies generally decrease, whereas loss factors increase for such the prestresses as external pressure, axial compression stress and torsional shear stress. Besides, it turned out through parametric studies that it is fairly difficult to find appropriate constructions of anisotropic laminated layers for which the both of natural frequency and loss factor become concurrently large. Considering the above, the following criterion optimizing vibrational characteristics of such structures as shells with the fairly large damping and the high frequency distribution density is proposed, i. e., that the least value of the product of frequency and loss factor for all vibrational modes should be maximized from the viewpoint of optimizing the free vibration reduction characteristics, in stead of the criterion to maximize the fundamental frequency which is one of the conventional concepts. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Analysis of Forced Vibration of Rotating Thick Shells of Revolution Subjected to Prestresses, Mitsuru Endo, Tsutomu Nishigaki, Takashi Maeda, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(645), 1423 - 1430, 2000 Summary:Numerical analysis method of transient forced vibration responses of thick rotating shells of revolution is developed. The method can consider the anisotropic laminated layers and the effects of prestresses such as the in-plane compression stress, internal pressure and torsional shear stress. Finite element method is applied using truncated conical shell element based on the first-order shear deformation theory, and the finite strain is considered to execute the non-linear analysis of the quasi -static displacements due to the rotation and prestresses except for the case of internal pressure. Transient responses of a laminated truncated conical shell and a partial spherical shell subjected to concentrated step and half-wave sinusoidal shock forces are calculated and compared with the previous results based on the classical shell theory. Finally, the effects of three kinds of prestresses are systematically examined by using a truncated conical shell model with the both ends clamped. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Unstable Vibration of Continuous Systems Subjected to Random Parametric Excitation, Mitsuru Endo, Tsutomu Nishigaki, Seiji Oka, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(645), 1431 - 1438, 2000 Summary:The vibrational behavior of continuous systems such as beams, plates and circular cylindrical shells subjected to random parametric excitations is examined mainly from the viewpoint of possibility of unstable phenomena. The vibrational responses of those continuous systems are analyzed by means of simulation method using random sample functions of trigonometric series generated by random numbers. It turned out that unstable phenomena occur even for the cases in which random parametric excitation inputs have the fairly wide-band power spectra whose dominant frequencies deviate from, for example, the twice of the natural frequencies of continuous systems. Besides, for such continuous systems as plates or shells which have the high frequency distribution density, unstable vibrations are generated concurrently in multi-vibrational modes. Finally, the experiment was carried out for a simply-supported beam subjected to the narrow-band random parametric excitation and it was ascertained that unstable vibrations really occur, and further the unstable figure domain made by the simulation analysis showed fairly good agreement with the experimental results. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Buckling Analysis of Rotating Prestressed Circular Cylindrical Shells (Analysis Based on the Finite Element Method), Mitsuru Endo, Takashi Maeda, Toru Kaneko, Tsutomu Nishigaki, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(643), 708 - 714, 2000 Summary:Buckling analysis of a rotating circular cylindrical shell subjected to the prestresses such as external pressure, axial compression stress and torsional shear stress is carried out through the frequency analysis. The finite element method using the truncated conical shell element based on the first-order shear deformation theory is applied, and the finite strain is taken into consideration to obtain the quasi-static displacements due to the rotation and prestresses, except for the case of external pressure. Numerical results show that for three kinds of prestresses, the buckling loads become larger as the rotational speed increases, and it turned out that it is sufficient to estimate the buckling loads for the case of no-rotation from the viewpoint of safety reliability. Besides, it was shown that for the case of torsional shear prestress, the linear analysis of quasi-static displacement leads to the physically incorrect result, i.e., the circumferential displacement diverges at some rotational speed and becomes the reverse to the torsional direction at the higher rotational speed. Thus, it should be noted that the authors' previously reported result that is derived through the linear analysis based on the quasi-analytical method using modified Galerkin method must be corrected. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Analysis of Radiated Sound from Arbitrary Configuration Solids Shocked by an Impulse (The Case in which a Given Impulse is applied to a Single Solid of Arbitrary Configuration), Mitsuru Endo, Tsutomu Nishigaki, Yuji Kawase, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(642), 406 - 413, 2000 Summary:Analysis method of radiated sound from arbitrary configuration solids shoked by an impulse is investigated mainly from the viewpoint of practical applicability. The analyses of vibrational response of solids and radiated sound from them are based on the Finite Element Method and the Boundary Element Method, respectively. And the both are formulated in the Laplace range and they are linked in such the meaning that the boundary conditions for BEM are directly given in this range by the Laplace transformed results of vibrational response of solids. The results of time domain of radiated sound and vibrational response are obtained by the numerical inverse Laplace transform using fast Fourier transform. As some examples of fundamental structure elements, straight and L -shaped beams, a circular plate and a ring are considered, and the theoretical results are compared with those of the experiments using the impulse hammer. It shows good agreement and it is proved that the proposed method is valid for practical use. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Proposition of an I-shaped Impact Damper for Continuous Systems and a Basic Study on its Vibration Suppression Effects, Mitsuru Endo, Tsutomu Nishigaki, Keigo Kuroda, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 66(641), 74 - 81, 2000 Summary:For the vibration suppression of flexible continuous systems, an I-shaped impact damper with parallel linear spring and dashpot is first proposed. And, as laboratory models, a beam and a Lshaped panel to which teflon and multiple impactors are installed are considered, and the equation of motion of those systems are formulated by the finite element method. Concerning the free vibration and the forced vibrations by harmonic and random excitations for those models, the results of numerical simulation and those of experiments are compared, and it shows the validity of theoretical modeling and the usefulness of the proposed I-shaped impact damper. Finally, on the ground of the theoretical analysis for the case of random excitation by band-limited white-noise, the basic examination of the multi-modes vibration suppression effects by multiple impact dampers is carried out. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.
- Vibration Control of a Beam with Piezoelectric Film Sensors/Actuators, NISHIGAKI Tsutomu, INOUE Hirofumi, ENDO Mitsuru, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 65(633), 1937 - 1945, May 25 1999 Summary:Vibration control of a flexible beam with piezoelectric film sonsors/actuators is investigated. Triangular-shaped piezoelectric films are bonded on the both surfaces of a flexible beam, and are treated as collocated sensor/actuator pairs. Equations of motions of the beam and sensor output are derived for two boundary conditions: 1) fixed-free, 2) both ends simply supported. Direct velocity feedback (DVFB) control law is employed, and closed-loop stability is analytically checked using Lyapunov's direct method. Forced vibration responses of the beams are calucutated under the condition that the system is harmonically excited. Analytical results show that first several bending modes can be controlled with reasonable feedback gains. In the simply supported case, anti-symmet-rical modes (even modes) are also efficiently controlled, and thus it is shown that the proposed control scheme is valid for multi-mode vibration control' of flexible beams.
- Vibration Control Experiments of a Simply Supported Beam with Triangular-Shaped Piezoelectric Film Sensor/Actuator, Tsutomu Nishigaki, Yoko Kawasaki, Mitsuru Endo, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 65(637), 3493 - 3498, 1999 Summary:Vibration control experiments of a simply supported beam using piezoelectric film (PVDF) sensor/actuator are carried out to verify that the triangular-shaped film pair is effective for multi-modes vibration control in comparison with the rectangular-shaped film pair. In the experiment, analog circuits are used to implement DVFB (Direct velocity feedback) control law. Frequency responses of displacemet of a beam subjected to a concentrated harmonic force are measured with sensor outputs and feedback voltages, and those show good agreement with the theoretical results. As predicted theoretically, it is shown in the present experiments that all of the first three vibrational modes are efficiently controlled by the triangular-shaped film sensor/actuator, whereas the rectangular-shaped film sensor/actuator has no control effect against the anti-symmetrical vibrational modes, i. e., the second mode. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.
- Analysis of Sound Radiation Characteristics of Rail by, Bem Mitsuru Endo, Tsutomu Nishgaki, Ko Mizuno, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 65(638), 3986 - 3991, 1999 Summary:Sound radiation characteristics of vertically vibrating rail are investigated to clarify the nature of rolling noise of high-speed railway, since the contribution of wheel movements to rolling noise is verified to be very small. The slab track is considered and steady state vibration responses of an infinite -length rail excited by a concentrated harmonic force is first obtained for various frequencies on the ground of the Bernolli-Euler beam theory and by applying the Fourier transform. Then, by using the Boundary Element Method based on the Helmholtz equation, the generated sound pressure is calculated under the boundary conditions of rail surface movements and rigid ground, and the sound radiation characteristics arc examined especially from the view-point of directivity. Besides, the influence of restoring and damping effects of the foundation of rail on the sound pressure level is studied. Finally, the theoretical results of sound pressure distribution are compared with the existing experimental results, and it shows fairly good agreement. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.
- Vibration Sensing and Control of a Flexible Beam Using Piezoelectric Films, NISHIGAKI Tsutomu, ODAWARA Yasushi, ENDO Mitsuru, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 63(615), 3728 - 3734, Nov. 25 1997 Summary:Multimodal vibration control of a cantilever beam using bonded piezoelectric film sensors and actuators is studied both theoretically and experimentally. Equations of motion of the Bernoulli-Euler beam with collocated bonded piezoelectric sensors / actuators are derived. Then, direct velocity feedback control is employed as the vibration control law, and applying Lyapunov's direct method, it is shown that this control law is stable for arbitrary vibration mode. Transient responses of the beam, with control and without control, are studied for the cases in which an impact force is applied to the tip of the beam. Numerical results and experimental results show good agreement, which shows the validity of the proposed control scheme. It is also shown that first three bending modes are efficiently controlled, and that in order to achieve more broadband vibration control, it is necessary to consider the dynamics such as extensional vibrations of the beam which is not considered in the present study.
- Analysis of Impact Sound in a Half Space Based on the Boundary Element Method, NISHIGAKI Tsutomu, SUZUKI Tomoyuki, ENDO Mitsuru, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 63(614), 3509 - 3515, Oct. 25 1997 Summary:This paper describes an analysis technique based on the boundary element method (BEM) for problems concerning transient sounds by impacted bodies of arbitrary shape that are in close proximity of a rigid infinite plane. The BEM is formulated using a new half-space Green's function which exactly satisfies the Laplace transformed Helmholtz equation and the rigid boundary condition on the infinite plane. The analysis is first carried out in the Laplace transformed domain using the boundary input values obtained by a numerical Laplace transform. Then, the results in the time domain are obtained by a numerical inverse Laplace transform. For a transient sound radiated by impacted bodies, transient acoustic radiation from a sphere and a cube impacted by a sphere are considered. The validity of the analytical results is examined by comparing it with the experimental results.
- Research on Transient Sound Radiated by Impacted Solid Bodies Based on the Boundary Element Method, Nishigaki Tsutomu, Ohyama Takeshi, Endo Mitsuru, Transactions of the Japan Society of Mechanical Engineers. C, Transactions of the Japan Society of Mechanical Engineers. C, 61(585), 1924 - 1929, May 25 1995 Summary:The analysis technique for problems concerning transient sounds radiated by impacted bodies is investigated by the boundary element method (BEM), and a general-purpose analysis program, which is available for any sound sources, is developed. The Laplace transformation of the Helmholtz equation is employed in the formulation of BEM. The analysis is first carried out in the Laplace transformed domain by using the boundary input values obtained by numerical Laplace transform. Then, the results in the time domain are obtained by numerical inverse Laplace transform. As a transient sound radiated by impacted bodies, transient acoustic radiation from a column and a cube impacted by a sphere are considered. The validity of these analytical results for time-dependent sound radiation is examined by comparing with the experimental results.
- Multimodal Vibration Control of a Cantilever Beam with Collocated Bonded Piezoelectric Film Sensors and Actuators, Tsutomu Nishigaki, Yasushi Odawara, Mitsuru Endo, Proceedings of MIMR, Proceedings of MIMR, 399 - 402, May 1995 , Refereed
- Vibration Analysis of A Gondola Suspended by Two Long Wire Ropes, Tsutomu Nishigaki, Takashi Saito, Proceedings of MOVIC, Proceedings of MOVIC, 768 - 773, 1992
- Effect of poling treatment on piezoelectric constant of pulsed laser deposited hydroxy apatite thin films, Tsutomu Nishigaki, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 631, 253 - 257, 2015 , RefereedSummary:It has been well known that bone has piezoelectric properties and these properties have been considered to be caused by the shift of the center of symmetry of the positive and negative electrical charge due to the strain of the collagen fibers included in the bone. Thus, it has long been considered that there were no piezoelectric effects in the hexagonal hydroxyapatite(HAp) which has center of symmetry of crystal. However, in recent years, the piezoelectric property of artificially synthesized HAp was reported. In the authors' previous report, a new result which showed the piezoelectricity of the hydroxyapatite(HAp) films fabricated by the pulsed laser deposition(PLD) method was reported. In this study, the effect of poling treatment on piezoelectric constant of pulsed laser deposited HAp films was investigated.
- Development of a piezoelectric polymer energy harvesting flag, Tsutomu Nishigaki, Proceedings of SPIE - The International Society for Optical Engineering, Proceedings of SPIE - The International Society for Optical Engineering, 8688, 86881K.1-86881K.7, 2013 Summary:In recent years, wind energy harvesting systems using piezoelectric materials have been studied by a lot of researchers. However, energy harvesting methods using flexible thin piezoelectric films had not been well developed due to the extremely small power generation. In this study, a piezoelectric wind energy harvesting method using high-polymer films was investigated experimentally. At first, the feasibility of the systems was shown in laboratory experiment by using various shapes, sizes, and boundary conditions of piezoelectric films subjected to the artificial wind airflow from consumer air blower. Then, a flag-type piezoelectric wind energy harvester was manufactured and the characteristic against natural winds was verified by outdoor experiments. © 2013 SPIE.
- A study of the transient sound radiated by impacted solid bodies based on the boundary element method, Tsutomu Nishigaki, Takeshi Ohyama, Mitsuru Endo, JSME International Journal, Series C: Dynamics, Control, Robotics, Design and Manufacturing, JSME International Journal, Series C: Dynamics, Control, Robotics, Design and Manufacturing, 39(2), 218 - 224, 1996 , RefereedSummary:The analysis of problems concerning transient sounds radiated by impacted bodies using the boundary element method (BEM) is investigated, and a general-purpose analysis program which is valid for any type of sound source is developed. The Laplace transformation of the Helmholtz equation is employed in the formulation of the BEM. The analysis is first carried out in the Laplace domain by using the boundary input values obtained by a numerical Laplace transform. Then, results in the time domain are obtained by a numerical inverse Laplace transform. As an example of transient sound radiated by impacted bodies, the transient acoustic radiation emanating from a column and a cube impacted by a sphere are considered. The validity of these analytical results for time-dependent sound radiation is examined through comparison with the experimental results.

- On the characteristics of warning sounds and generating speakers (Toward development of the sound which contains both recognizable waveform and frequency band to the elderly), Tsutomu Nishigaki, u-Healthcare2015, 2015 12
- 圧電フィルムアクチュエータが貼付された平板の振動解析, NISHIGAKI TSUTOMU, UMAGOSHI IZUMI, 日本機械学会関西支部定時総会講演会講演論文集, 2014 03 18
- 圧電フィルムセンサ/アクチュエータによる波動吸収原理に基づく柔軟アームの振動制御, NISHIGAKI TSUTOMU, OKA SHUNSUKE, Dyn Des Conf (CD-ROM), 2014
- はりの強制振動応答を利用した薄膜の圧電率の同定, NISHIGAKI TSUTOMU, 日本機械学会年次大会講演論文集(CD-ROM), 2013 09 07
- Project Practice on Universal Design by using Digital Mannequin, 2013 06
- Measurement of Piezoelectric Properties of Pulsed Laser Deposited Hydroxyapatite Thin Films on Platinum or Titanium Substrate, Tsutomu Nishigaki, Hiroak Nishikawa, Masanobu Kusunoki, Shigeki Hontsu, International Synposium on Apatite and Correlative Biomaterials, 2013 06
- 隣接した平板スピーカ・アクティブ制御ユニットによる壁面透過騒音制御, NISHIGAKI TSUTOMU, NAKANO HIROKI, 日本騒音制御工学会研究発表会講演論文集, 2013 04 23
- Education on Universal Design by using Digital Mannequin in Kinki University, HIROKAWA NORIYASU, NISHIGAKI TSUTOMU, OMASA MITSUSHI, HIROSE SHOZO, 日本人間工学会関西支部大会講演論文集, 2012 12 08
- はり振動を利用した薄膜圧電素子の圧電率の同定, NISHIGAKI TSUTOMU, ASAI MISAKO, 日本機械学会機械材料・材料加工技術講演会論文集(CD-ROM), 2012 11 29
- Education of Universal Design by using Digital Mannequin, HIROKAWA NORIYASU, NISHIGAKI TSUTOMU, OMASA MITSUSHI, HIROSE SHOZO, 日本機械学会設計工学・システム部門講演会論文集(CD-ROM), 2012 09
- 平板スピーカを用いた壁面透過低周波騒音のアクティブ遮音, NISHIGAKI TSUTOMU, KUSAKA NAOYA, システム制御情報学会研究発表講演会講演論文集(CD-ROM), 2012 05 21
- 平板スピーカを用いた能動遮音システムの小型・高性能化の検討, NISHIGAKI TSUTOMU, システム制御情報学会研究発表講演会講演論文集(CD-ROM), 2011 05 17
- 637 Multimodal Vibration Control of a Plate by a Smart DamperUsing Laminated Piezoelectric Films, NISHIGAKI Tsutomu, HAGIWARA Yusuke, ENDO Mitsuru, Dynamics & Design Conference, 2007 09 25 Summary:Piezoelectric film has two effects of direct piezoelectric effect and inverse piezoelectric effect. These effects can be used for the vibration control of flexible structures. In the authors' previous reports, a self-sensing actuator with laminated piezoelectric films was proposed and the vibration control effects against first and second mode of a beam and first mode of a rectangular plate were shown. However, vibration control effect against multimode of two-dimensional structure was not shown yet. Therefore, in this paper, a self-sensing actuator using laminated triangular piezoelectric films was proposed and its analytical model was derived. Then the validity of the proposed method was shown by comparing the results of an experiment of applying voltage to a triangular piezoelectric film actuator bonded on the plate, with that of theoretical analysis. Finally, multimodal vibration control of simply-supported plate was studied by numerical analysis.
- 317 Improvement of On-vehicle-type ANC Devices for Noises of Railway Wheel / Rail System, ENDO Mitsuru, YAOITA Akira, NAGATA Daichi, IWANO Koji, NISHIGAKI Tsutomu, Dynamics & Design Conference, 2007 09 25 Summary:Concerning the on-vehicle-type ANC devices based on the wave absorption principle for wheel / rail system, new concept of device construction was proposed to prevent the howling and to realize downsizing , i.e., the secondary sound actuator is to be separated from the detecting microphone of primary noise by the distances of 1/2, 3/8 and 1/4 times of wave length of dominant frequency (800Hz) of rolling noise. The validity of new idea was first ascertained by means of BEM simulation analysis and then the experiments using three kinds of devices were actually executed, showing the improved ANC effects for the fairly high primary noise level almost comparable to the practical level
- 305 Characteristic Analysis and Evaluation of Rolling Noise of Railway Wheel / Rail System, ENDO Mitsuru, NISHIGAKI Tsutomu, TAKEKAWA Masahiro, Dynamics & Design Conference, 2007 09 25 Summary:In order to elucidate the characteristics of rolling noise of wheel / rail system which is to be the main cause of the conventional railway noises, first the coupling vibration analyses were carried out by using an infinite length rail model with tread surface roughness and FEM model of wheel, and then based on BEM with the boundary conditions of obtained vibration responses , the acoustic radiation powers and the distribution of SPL of sound fields on both of the slab and ballast tracks were calculated for the wheels with straight , TGV-type and corrugated web. Examining the influences of wheel configurations to the rolling noise, the methods of countermeasures to reduce that noise were implied.
- Active Vibration Control Using Piezoelectric High-Polymer Films, NISHIGAKI TSUTOMU, 日本機械学会機械材料・材料加工技術講演会講演論文集, 2006 11 25
- 622 Development of a Distributed Smart Damper Using Laminated Piezoelectric Films with Self-Tuning Function, NISHIGAKI Tsutomu, TAKIGUCHI Shinya, ENDO Mitsuru, Dynamics & Design Conference, 2006 08 06 Summary:In the authors' previous report, a self-sensing actuator with laminated piezoelectric films was proposed, and the validty of the proposed method was shown by performing their vibration control experiment of a beam and a rectangular plate. However, the slight difference between circuit components such as piezoelectric capacitance and their variation with time and temparature made the closed-loop system unstable. Therefore, variable resistors needed to be fine-tuned manually so as to keep the bridge circuit balanced. However, this adjustment work was cumbersome and complicated in that it was needed to be done by trial and error. In this study, a distributed smart damper using four laminated piezoelectric films is developed by using an analog multiplier and a digital signal processor in order to provide the bridge circuit with self-tuning function. In the experiment, this smart damper is applied to a cantiliver beam. After operating the self-tuning function according to the least-mean-square algorithm, free vibration control of the first mode of a cantilever beam is performed with a convergent parameter. It is verified that enough control effect is actually obtained and this control effect is almost equal to the effect obtained in cases where the bridge circuit is tuned manualy.
- 734 Active Control of Railway Wheel/Rail Noises by On-vehicle-type Devices, ENDO Mitsuru, YAOITA Akira, MAEDA Natsuko, O-OKANDA Kozue, NISIGAKI Tsutomu, Dynamics & Design Conference, 2006 08 06 Summary:The possibility of a concept of active sound cancellation control based on the wave absorbing principle of conventional railway wheel/rail rolling and impact noises by on-vehicle-type devices was examined. First, theoretical simulations on the basis of BEM were executed, and then the experiments of active noise control were carried out by using multi-device-units installed on the panel system simulating the floor/side wall of railway cars, where both the simulated random rolling noise and impact noise measured in the real field were used. As a result, it was verified that the sound cancellation effects are actually observed over the relatively broad seeable space from the rail, showing the validity of the proposed concept.
- 737 Development of an Active Sound Absorbing Unit of the Transmission Noise through a Wall using a Plate Speaker, NISHIGAKI Tsutomu, KUNIYOSHI Syunichi, ENDO Mitsuru, Dynamics & Design Conference, 2006 08 06 Summary:An acive sound absorbing device unit of the transmission noise through a wall, using a plate planewave speaker as the secondary sound source, was developed toward effective suppression of aircraft interior noise. The controller was designed using reference accelerometer attached on the wall, and based on the Filtered-x LMS algorithm, its system identification was in advance performed so as to minimize sound level at one observation point, and then act as an off-line controller. At first, control effects were estimated by the numerical analyses using the system model identified from the actual experimental devices. Then, active sound absorbing experiments were performed with band limited white noise applied to the unit, and it was shown that enough control effects were obtained at plural observation points located in three dimensional space.
- 719 Wave Absorbing Control of a Cantilever Subjected to the Random Excitation by Piezoelectric Film Sensor/Actuator, NISHIGAKI Tsutomu, OGAMI Kazunori, ENDO Mitsuru, Dynamics & Design Conference, 2005 08 22 Summary:A wave absorbing control method using piezoelectric film sensor/actuator, namely quasi-waveabsorbing control which is based on relative displacement control, of a flexible thin-walled cantilever beam subjected to random displacement excitation is investigated. Vibration control experiment is performed with the triangular shaped sensor and the rectangular shaped actuator bonded on both surfaces of the beam, and velocity feedback control law which is expected to be most effective in the theoretical analysis is applied. Fixed boundary of the cantilever is subjected to limited bandwidth random noise excitation, and the relative displacement of the beam is measured. It is verified that good vibration control effects are obtained for the bandwidth containing three lowest vibration modes.
- 355 Validity of Sound Decreasing Structures with Sound Absorbing Materials in the Three Dimensional Acoustic Fields, ENDO Mitsuru, NISIGAKI Tsutomu, TAKEKAWA Masahiro, Dynamics & Design Conference, 2005 08 22
- 357 Influences of Wheel Configurations on the Acoustic Radiation Power of Rolling Noise of Wheel/Rail Coupling System, ENDO Mitsuru, NISIGAKI Tsutomu, RO Ei, Dynamics & Design Conference, 2005 08 22 Summary:Concerning the rolling noise of wheel/rail coupling system, first the power spectrum of contact force between wheel and rail is calculated by random vibration analysis and besides the vibration responses of rail and wheel is obtained by use of Timoshenko beam theory for rail in addition to FEM model for wheel .Then, using those vibration responses as the boundary conditions of acoustic analysis of BEM, the acoustic powers radiated from wheel and rail are obtained and the rations of respective power to total power are estimated for three kinds of confgurations of wheel, that is, straight web wheel, corrugated web wheel with six circumferential wave number and TGV-type wheel.Concerning the rolling noise of wheel/rail coupling system, first the power spectrum of contact force between wheel and rail is calculated by random vibration analysis and besides the vibration responses of rail and wheel is obtained by use of Timoshenko beam theory for rail in addition to FEM model for wheel .Then, using those vibration responses as the boundary conditions of acoustic analysis of BEM, the acoustic powers radiated from wheel and rail are obtained and the rations of respective power to total power are estimated for three kinds of confgurations of wheel, that is, straight web wheel, corrugated web wheel with six circumferential wave number and TGV-type wheel.
- 358 Influences of Road Surface Characteristics on Automobile Tire/Road Noises, ENDO Mitsuru, NISHIGAKI Tsutomu, TSUKUI Norio, Dynamics & Design Conference, 2005 08 22 Summary:Noticing the noise reduction effects of the drainage asphalt pavement, the method of estimation of radiation characteristics of automobile tire/road noises and the road design concept of reducing such noises are examined. By using FEM, the tire vibration responses depending on the grain size of road texture are obtained and regarding those responses and the normal acoustic impedance of the finite area simulating road surface as the boundary conditions for acoustic analysis by BEM, the sound pressures radiated from the tire on the both of the dense and porous asphalt pavements are calculated. As a result, it is verified that in the drainage asphalt pavement, the tire/road noise is more reduced than in the dense pavement by the suppression of horn effect in addition to the excess attenuation due to sound absorbing effect of porous asphalt.
- 301 Influence of the Wheel Configurations upon the Rolling Noise of the Railway Wheel /Rail System, ENDO Mitsuru, NISHIGAKI Tsutomu, KAMEZAKI Nobuhiro, Dynamics & Design Conference, 2004 09 27 Summary:The vibration analyses in which the head of the wheels is harmonically excited in radial direction were carried out by using FEM for the wheels of Straight web. TGV-type web and Wavy web with four kinds of circumferential wave number, and then by taking those vibration responses as boundary conditions the acoustic analyses using BEM were conducted to obtain the acoustic radiation power. And by random vibration analyses considering the rail surface roughness, the mean square velocities of rail at the contact point between rail and wheel were calculated. From the above results, the sound radiation powers of various-type wheels were examined in order to clarify the influence of wheel configurations upon the rolling noise of the railway wheel / rail system and to get the fundamental knowledge towards the optimal design of the configurations of the wheels with wavy web.
- 319 Basic Study on the Active Sound Cancellation Control of the Railway Wheel/Rail Noises by the On-vehicle-type Devices, ENDO Mitsuru, YAOITA Akira, MAEDA Natsuko, NISHIGAKI Tsutomu, Dynamics & Design Conference, 2004 09 27 Summary:The concept of the active sound cancellation control of the railway wheel/rail noises by the On-vehicle-type devices is presented. And the apparatus of randomly exciting 60kg rail by the electromagnetic shaker which is enclosed with the panel system simulating the floor/side wall of the railway car was constructed. Further, one unit of the devices which realizes in principle the sound cancellation control of the see-through space was manufactured and the parabola-microphone and actuating speaker was installed on it in addition to the controller consisting of the analog electrical band-pass filter circuit group. And it was verified that the sound cancellation control effects are observed actually for the both cases of a speaker and the randomly excited rail system which were regarded as the primary sound sources.
- 320 Development of an Active Sound Absorbing Device Unit of the Transmission Noise through a Thin Plate Using a Plate Speaker, NISHIGAKI Tsutomu, TOKUSHIGE Takumi, ENDO Mitsuru, Dynamics & Design Conference, 2004 09 27 Summary:The active sound absorbing device unit of the transmission noise through a thin plate using a plate plane-wave speaker as the secondary sound source was developed and its lightening and compacting construction methods of elements was examined by trying the various combinations of elements. The controller is designed on the basis of the Filtered-x LMS adaptive algorithm by using DSP under the condition that the thin plate is subjected to the band-limited white noise. It was verified by the actual control experiments that the improvement from the view-point-of lightening of the unit is attained as a whole by the passive insulation effect of the speaker elements in addition to the active sound absorbing effect in comparison with the case in which a plane-wave speaker consisting of the piezoelectric film was used.
- 147 Design Methods and an Application of the Dual Dynamic Vibration Absorber for Large-scale Structures with Low Frequencies, ENDO Mitsuru, NISHIGAKI Tsutomu, YANAGIMOTO Hirotada, Dynamics & Design Conference, 2004 09 27 Summary:The design methods of the optimum tuning and damping of the dual dynamic vibration absorber (D-DVA) for large-scale structures with very low frequencies were presented, arid the optimal construction layout which minimizes the undesirable moment applied to the base was examined. And then, for the both cases of displacement and force excitations, the approximate expressions for design parameters were proposed. Further, it was indicated that in the case of installing the D VA to the continuum structures subjected to the displacement excitation, the introduction of the new concept of the equivalent inertia mass in addition to the conventional equivalent mass and stiffness at the point of installation becomes necessary. Finally, by applying the present dual DVA to the vibration suppression of the first and the second vibration modes of a large-scale framework structure, the simulation results were obtained, showing the effectiveness of the present dual dynamic vibration absorber.
- Vibration Control of a Flexible Beam Using Piezpelectric Film Sensors and Multilayered Actuators, NISHIGAKI Tsutomu, SHINJO Akiko, ENDO Mitsuru, Dynamics and Design Conference, 2003 10 30 Summary:Vibration control of a flexible beam using piezoelectric film sensors and multilayered actuators is investigated. At first, the method of multilayered piezoelectric actuator is proposed for the purpose of improvement in vibration control effect against relatively thick structure. In the proposed technique, multilayered piezoelectric films are connected in parallel electrically and are driven simultaneously by the control voltage. Then, multilayered actuator is actually applied to a cantilever beam and by measuring the amplitude of semi-static displacement at the tip of the beam, it is shown that the actuator force generated by the proposed miltilayered actuator improves for the same magnification as the number of films. Finally, proposed method is applied with the piezlelectric film sensor to the transient vibration control of the cantilever beam and it is verified that the vibration control effect actually improves and the theory agrees well with the experiment.
- 404 Sound Decreasing Effects of Sound Absorbing Material Structures Installed on the Vibrating Rigid Surface, ENDO Mitsuru, NISIGAKI Tsutomu, KURAYA Tatsunori, Dynamics & Design Conference, 2003 09 16 Summary:Sound decreasing effects of sound absorbing material structures installed on the moving rigid surface were verified experimentally for both the stationary and the nonstationary cases by using the one-dimensional acoustic tube. The decreasing effects were evaluated in the frequency spectrum domain by taking the discrete Fourier Transform for the nonstationary case, and almost 70% sound pressure decreasing effect was observed at the maximum in the range of 0.5〜3kHz for the hard porous or fiber alminum sound absorbing material structures with back air space. Then two kinds of quantitative estimation methods of those decreasing effects were examined.
- 407 Active Sound Absorption of Transmission Noise of a Thin Plate Using a Piezoelectric Film Speaker, NISHIGAKI Tsutomu, MORITA Hidenori, ENDO Mitsuru, Dynamics & Design Conference, 2003 09 16 Summary:The concept of the active sound absorption method using thin and membranous piezoelectric film speaker is proposed toward the suppression of aircraft interior noise, especially large turbo-fun jet plane. At first, an active sound absorber unit is constructed with a secondary piezoelectric film speaker and an reference accelerometer, and the controller is designed using Filtered-x LMS adaptive filtering. Then, the active sound absorber unit is applied to the suppression of the transmitted sound through a thin plate, and by observing the sound attenuation at plural points, it is ascertained that the proposed method can actively absorb the transmitted sound, which has the property similar to the aircraft interior noise. Finally, a way of construction of the control system with proposed active sound absorber unit is presented for aircraft interior noise reduction.
- Sound Decreasing Effects of Sound Absorbing Material Structures Installed on the Vibrating Rigid Surface, ENDO Mitsuru, NISIGAKI Tsutomu, KURAYA Tatsunori, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2003 09 15 Summary:Sound decreasing effects of sound absorbing material structures installed on the moving rigid surface were verified experimentally for both the stationary and the nonstationary cases by using the one-dimensional acoustic tube. The decreasing effects were evaluated in the frequency spectrum domain by taking the discrete Fourier Transform for the nonstationary case and almost 70% sound pressure decreasing effect was observed at the maximum in the range of 0.5 ∿ 3kHz for the hard porous or fiber alminum sound absorbing material structures with back air space. Then two kinds of quantitative estimation methods of those decreasing effects were examined.
- Active Sound Absorption of Transmission Noise of a Thin Plate Using a Piezoelectric Film Speaker, NISHIGAKI Tsutomu, MORITA Hidenori, ENDO Mitsuru, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2003 09 15 Summary:The concept of the active sound absorption method using thin and membranous piezoelectric film speaker is proposed toward the suppression of aircraft interior noise, especially large turbo-fun jet plane. At first, an active sound absorber unit is constructed with a secondary piezoelectric film speaker and an reference accelerometer, and the controller is designed using Filtered-x LMS adaptive filtering. Then, the active sound absorber unit is applied to the suppression of the transmitted sound through a thin plate, and by observing the sound attenuation at plural points, it is ascertained that the proposed method can actively absorb the transmitted sound, which has the property similar to the aircraft interior noise. Finally, a way of construction of the control system with proposed active sound absorber unit is presented for aircraft interior noise reduction.
- Study on Impact Sound at the Joint of Rail in Urbar Railway, ENDO Mitsuru, NISHIGAKI Tsutomu, KUROKAWA Kenya, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2002 09 13 Summary:Characteristics of the impact sound at the joint of rail in the urban railway are investigated. The rail is modeled by a free-free Euler-Bernoulli beam on the Winkler foundation with springs and dashpots and the acceleration in the Laplace transform domain is calculated when a wheel impacts the one end of the rail vertically. Then the Laplace transformed radiation sounds are calculated on the basis of the Boundary Element Method by considering the flux which is expressed by the product of the above acceleration of rail and the air density as the boundary conditions. In the BEM, the rail surface is discretized by using the triangular linear element. And the time histories of radiated sounds from the rail are obtained by conducting the numerical inverse Laplace transform. On the ground of those results, the characteristics of radiated impact sounds from the joint of the rail are examined in addition to the generation mechanism of those sounds.
- Multimodal Vibration Control Using a Self-sensing Actuator with Laminated Piezoelectric Films, NISHIGAKI Tsutomu, TATSUKAWA Tomoaki, ENDO Mitsuru, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2002 09 13 Summary:In the authors' previous report, a self-sensing actuator using laminated piezoelectric films with differnt thickness and area was proposed, and the validity of the proposed method against the lowest vibration mode was shown by performing vibration control experiments of a cantilever beam and a simply-supported plate. In these experiments, however, only rectangular shaped films were used, and furthermore, vibration control effects against higher modes was not verified experimentally. In this report, the present method is applied to multimodal vibration control of simply supported beam by using piezlelectric two films of differnet shapes and orientations. Two types of self-sensing actuators are proposed and five conbinations of thickness, shape, and oriantations of the two piezoelectric films are considered and vibration control effects are compared theoretically. Finally, vibration control experiments are performed using laminated triangular-shaped piezoelectric two films with different skew angle, and it is shown that vibration control effect was obtained against first and second modes of the beam.
- Study on Dual Dynamic Vibration Absorber for Large-scale Low Frequency Structures, ENDO Mitsuru, NISIGAKI Tsutomu, YANAGIMOTO Hirotada, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2002 09 13 Summary:Equation of motion of the dynamic vibration absorber for large-scale low frequency structures proposed previously is derived for the case with dual auxiliary systems and the numerical method of design of the quasi-optimal tuning and damping conditions of the dual case is presented. And it is verified by the simulation that the vibration suppression effects are improved in comparison with the single case. Then, applying to the three-degree-of freedom system with the fundamental frequency of 0.1 Hz, the superiority of the present method to the conventional design concept is shown in the low frequency range. Finally, the prototype of the present dual dynamic vibration absorber was manufactured to apply to the one-degree-of-freedom system with the natural frequency of 0.69hz and the vibration suppression effects were actually ascertained through the experiments of the free vibration and frequency response.
- Basic Study on the Pattern Excitation Sound of Automobile Rotating Tyres, ENDO Mitsuru, NISHIGAKI Tsutomu, YAMAUCHI Jun, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2002 09 13 Summary:A model of automobile rotating tyre is constructed by the Finite Element Method using the truncated conical shell element based on the first-order shear deformation theory. And in order to investigate basically the characteristics of tread pattern excitation sounds, the influences of tread pattern pitch number and pattern arrangement on the vibrations of tyre surface are examined by approximating the pattern exciting mechanism by the sinusoidal contact pressure loading from the earth. As a result, it turns out that the vibration amplitude of tyre decreases as the number of pattern pitch increases and besides the pattern becomes stagger-type for almost all automobile running speeds. And as to the distribution of tyre surface vibration amplitudes for the circumferential direction, the vibration amplitudes become remarkably large at the parts of the trailing and leading edges.
- 410 Modeling of a Rolling Automobile Smooth Tyre and its Vibrational Behaviors, ENDO Mitsuru, NISHIGAKI Tsutomu, CHIDA Takafumi, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2001 08 03 Summary:A precise modeling of a rolling automobile smooth tyre is carried out and through the analyses of its vibrational behaviors the mechanism of the noise generation is considered. The analysis is formulated by the Finite Element Method using a truncated conical shell element and includes the effects of the inner pressure, rotation, laminated anisotropic layer structure and damping matrix re-constructed from the modal damping ratios. Not only the linear but also the non-linear vibration analysis is executed by considering the effect of large deformation. The linear vibration response to the contact load with the smooth earth becomes the standing wave forms on the stationary co-ordinate, whereas the non-linear vibration response shows some amount of harmonic vibration components of tyre surface, and it results in the fact that the noises possibly generate even from a smooth tyre.
- 411 Sound Decreasing Effects of Sound Absorbing Material Structures on the Vibrating Rigid Surface, ENDO Mitsuru, NISHIGAKI Tsutomu, KURAYA Tatsunori, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2001 08 03 Summary:It was investigated experimentally whether the sound decreasing effects of sound absorbing material structures on the sinusoidally vibrating rigid surface are obtained or not. In the experiment, the one-dimensional acoustic tube was used and its one end is excited by the sound absorbing material structure and the other end is closed by glass wool. The experiments showed that almost 70% sound pressure decreasing effect is obtained at the maximum in the frequency range of 1〜3kHz for the hard porous or fiber aluminum sound absorbing materials with the back air space made by using honeycomb structures. And it is observed that the frequency dependency of this decreasing effects is qualitatively and almost quantitatively coincident with the root of reflectivity of the stationary absorbing material structure. But, for the urethane foam, this tendency could not be observed. It is supposed to be the flexible vibrational characteristics of urethane foam.
- 425 Quasi-Wave-Absorbing Control of Canilever Beam Using Piezoelectric Film Sensor/Actuator, NISHIGAKI Tsutomu, KAWANO Atsushi, ENDO Mitsuru, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2001 08 03 Summary:A wave absorbing control method, namely quasi-wave-absorbing control, of a harmonically excited cantilever beam using piezoelectric film sensor/actuator is investigated. At first, based on the relative coordinate system, fundamental equations are formulated using wave propagation characteristics of the beam. And then, five control laws so as not to generate the reflected waves at the tip of the beam are derived with the shapes of both piezoelectric sensor and actuator taken into consideration. Theoretical analyses of steady state responses show that based on the proposed method, almost equivalent vibration control effects can be obtained in comparison with those obtained by the conventional wave absorbing control method based on the absolute coordinate. Finally, vibration control experiment is performed with the triangular shaped sensor and the rectangular shaped actuator bonded on both surfaces of the beam, and velocity feedback control law which is expected to be most effective in the theoretical analysis is applied and it is verified that good vibration control effects are obtained for three lowest vibration modes.
- 426 Development of a Self-sensing Actuator with Laminated Piezoelectric Films : Toward the Smart Vibration Control of Two-Dimensional Structure, NISHIGAKI Tsutomu, MORITA Hidenori, ENDO Mitsuru, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2001 08 03 Summary:A self-sensing actuator constructed by four laminated piezoelectric films is developed toward the smart vibration control of two-dimensional structures. First, three kinds of mechanisms of self-sensing acutuators with two or four piezoelectric films laminated are proposed by examining the combinations of film construction and bridge circuits of analog electric controllers. And those self-sensing actuators are applied to the free vibration control of the first mode of a cantilever beam and it is ascertained that the vibration suppression effects are obtained by all the three mechanisms and the theories show good agreements with the experiments. Finally, the one mechanism constructed by four laminated piezoelectric films is applied to the vibration control of a simply-supported rectangular plate as an example of two-dimennsional structutures and it is verified that the vibration control effect is actually obtained and the theory agrees well with the the experiment.
- 632 Study on a Dynamic Vibration Absorber for Large-scale Structures with Low Natural Frequencies, ENDO Mitsuru, NISHIGAKI Tsutomu, MURAYAMA Masami, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2001 08 03 Summary:A new-type of the dynamic vibration absorber for large-scale structures with very low frequencies is proposed. It utilizes the rotational moment of inertia of bar-type mass instead of the conventional concept of utilizing the inertia force of the mass of the auxiliary vibrational system. The optimal tuning and damping conditions of the proposed dynamic vibration absorber are derived by the Fixed Point Theory. Then, this design concept is applied to the first mode with frequency O.lHz of the three-degree-of-freedom system, and the superiority of the proposed vibration absorber in low frequency range is verified. Finally, a prototype of the proposed device was manufactured and the experiments of the free vibration and the frequency response were conducted, and the validity of the theory was ascertained.
- 236 Analysis Method of the Nonstationary Response of Acoustical-Structural Coupling Systems, ENDO Mitsuru, NISHIGAKI Tsutomu, TOKIZAKI Tomoyuki, 振動・音響新技術シンポジウム講演論文集, 2001 06 05 Summary:This paper proposes the numerical analysis method of the nonstationary response of acoustical-structural coupling systems. The acoustical analysis is formulated by the Boundary Element Method based on the hyper-singular boundary integral equation. The structural analysis is formulated by the Finite Element Method using the triangular thin plate element. Those fundamental equations are coupled by using the force equilibrium and the flux continuity conditions in the Laplace transformed domain, and the time history of nonstationary responses is obtained by the numerical inverse Laplace transform. The validity of the proposed method is examined in comparison with an analytical result and besides by conducting the experiments of nonstationary excitation of thin plates installed in the rectangular acoustic tube which is excited by a sinusoidal sound pressure from the planewave-driving type speaker. Finally, a few numerical calculation examples are shown. Those analyses deal with the flexible straight and L-shaped acoustic tubes which are exited by the sinusoidal pressure generated at the one end of acoustic tubes.
- B9 Vibration Control of Flexible Structures by Piezoelectric Films, NISHIGAKI Tsutomu, ENDO Mitsuru, スペース・エンジニアリング・コンファレンス講演論文集 : Space Engineering Conference, 2001 01 11 Summary:In this paper, active vibration control of flexible structure by high-polymer piezoelectric films, which aims for the realization of smart structures, is investigated. At first, active vibration control method using piezoelectric films as sensor and actuator is discussed and the concept of distributed vibration control method is introduced. Then, several examples which are the author's studies are shown. The topics included are vibration control experiments of cantilever beams using rectangular-shaped sensor/actuator pairs, vibration control experiments of simply supported beams using a triangular sensor/actuator pair, wave absorbing control of cantilever beams using two pairs of triangular sensor/actuator, and vibration control experiments of cantilever beams and circular rings by a self-sensing actuator using piezoelectric films of different thickness. Finally, an overview of this study toward the future is presented.
- Systematic Examinations of Vibration Suppression Effects of Dynamic Vibration Absorber Depending on the Design Criteria and Excitation Forms, ENDO Mitsuru, NISHIGAKI Tsutomu, NAKASU Yoshihiro, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2000 09 01 Summary:As an example of passive vibration control devices, the dynamic vibration absorber installed in the main system of no-damping is considered and the vibration suppression effects for free vibration responses and forced steady-state and nonstationary responses are systematically examined as to the cases in which the device is desighned according to the four typical design criteria, i.e., the conventional frequency shaped response function method (FPT), the linear quadratic optimal control theory (LQC), the minimum variance criterion (MVC) and the eigenvalue optimization criterion (EOC). As a result, the device designed by FPT, LQC and MVC shows almost equivalent vibration suppression effects and has a fairly good robustness, whereas EOC shows the worst effects of all except the settling time of free vibration. As another result, the frequency response evaluation method widely used as the criteria, for example, of transmission loss of noise insulating wall transmission coefficient of silencer or H^∞ control theory turned out to be not necessarily valid especially for the nonstationary excitations.
- Study on the Impact Damper for Large-scale Flexible Structures, ENDO Mitsuru, NISHIGAKI Tsutomu, KURODA Keigo, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2000 09 01 Summary:An I-shaped impact damper for large-scale flexible structures was manufactured by way of trial using the machine elements of coil springs and magnet dampers. By installing it in the one degree-of-freedom system with the natural frequency less than 1Hz, the vibration suppression effects were ascertained for the steady-state harmonic responses. Secondly, on the ground of the numerical simulation, the vibration suppression effects and the appropriate placement method of multiple I-shaped impact dampers were examined by applying those to a large plane framework structure and studying the reduction of the first two resonance peaks, and it showed the effectiveness of the proposed I-shaped impact damper for large-scale flexible structures.
- Multimodal Vibration Control of a Flexible Beam Using Piezoelectric Films with Different Thickness and Shape, NISHIGAKI Tsutomu, KAMATA Yasuhiro, ENDO Mitsuru, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2000 09 01 Summary:In the authors' previous report, a smart and simplified self-sensing actuator technique using piezoelectric films with different thickness and area was proposed, in which two rectangular shaped piezoelectric films are bonded on one surface of the structure and treated as two capacitors in the active RC bridge circuit. The validity of the proposed method was shown by performing vibration control experiments of a cantilever beam and a circular ring. In this report, the present method is applied to multimodal vibration control of simply supported beam as fundamental flexible structure. At first, fundamental equations of the system based on the proposed method are derived using energy principle and vibration control effects are estimated by numerical analysis to show effective shapes of the two films for multi-mode vibration control of simply supported beam.
- Active Vibration Control by High-polymer Piezoelectric Films, NISHIGAKI Tsutomu, 材料力学部門分科会・研究会合同シンポジウム講演論文集, 2000 03 29 Summary:This paper deals with active vibration control of flexible structure by high-polymer piezoelectric films, which is based on the concept of smart structure. At first, characteristics and problems of active vibration control method using piezoelectric materials as sensor and actuator are discussed. Then, the concept of distributed vibration control method is introduced and several examples from the author's studies are shown. Included in the topics are vibration control experiments of cantilever beams using rectangular-shaped sensor/actuator pairs, vibration control experiments of simply supported beams using triangular sensor/actuator pair, wave absorbing control of cantilever beams using two pairs of triangular sensor/actuator, vibration control experiments of cantilever beams and circular rings by a self-sensing actuator using piezoelectric films of different thickness. Finally, an overview of this study toward the future is presented.
- Examination of Rail Cross-sectional Configuration for Reducing the Rolling Noise of High-speed Trains, ENDO M, NISHIGAKI T, MIZUNO K, 日本音響学会研究発表会講演論文集, 2000 03 01

- A New Shaping Design Method of Distributed Piezoelectric Film Sensor/Actuator for Vibration Control of Flexible Beams, NISHIGAKI TSUTOMU, Mem Sch Biol Orient Sci Technol Kinki Univ, 22, 1, 17, 2008 09 30 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902214232351308
- Membrane for Calming Vibration : Vibraion Control by High-polymer Piezoelectric Films, ENDO Mitsuru, NISHIGAKI Tsutomu, Journal of the Japan Society of Mechanical Engineers, 102, 962, 7, 10, 1999 01 05 , http://ci.nii.ac.jp/naid/110002438834

- Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Design and prototype manufacturing of a smart flexible arm based on the wave absorbing principle, In this study, a wave absorbing technique, i.e. the technique which cancels the reflection wave at the end point of the flexible thin structure, was investigated using piezoelectric films. At first, a cantilever beam, which can be applied to the flexible rotating arm, was introduced as the controlled structural model. Then, a smart cantilever beam, on which appropriately shaped piezoelectric film sensors and actuators were bonded, was manufactured. Theoretical analysis and experiments were performed and it was shown that vibration control effects will be expected for broad band frequency range including several vibrational modes. Furthermore, vibration control effects in the laboratory experiment showed good agreement with those in the theoretical analysis when the excitation frequencies were low enough. It was also confirmed that it is difficult to apply the proposed method to the flexible rotation arms, since the influence of the inertial force cannot be neglected in the experiments.