• Title, Summary, Keyword: Sound-Structure Interaction

Search Result 37, Processing Time 0.032 seconds

A Free Vibration Analysis of Sound-Structure Interaction Plate (구조-음향 연성평판의 자유진동해석)

  • Lee, Dong-Ick;O, Jae-Eung
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.20 no.8
    • /
    • pp.2546-2554
    • /
    • 1996
  • In order to investigate the characteristics of sound-structure interaction problems, we modeled a rectangular cavity and the flexible wall of the cavity. Because the governing equations of motion are coupled through velocity terms, we could redefine them using the velocity potential. We calculated the natural frequencies of plate using orthogonal polynomial functions which satisfy the boundary conditions in the Rayleigh-Ritz Method. As the result, comparisons of theory and experiment show good agreement. and using orthogonal polynomial functions which satisfy the boundary conditions in the Rayleigh-Ritz method show useful method for sound-structure interaction problems too.

A free vibration analysis of sound-structure interaction plate having a small cut-out (부분적으로 열린 구조-음향 연성평판의 자유진동해석)

  • Oh, Jae-Eung;Rhee, Dong-Ick
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.10
    • /
    • pp.1666-1673
    • /
    • 1997
  • In order to investigate the characteristics of sound-structure interaction plate having a cut-out, we modeled a rectangular cavity and the flexible plate of the cavity. Because the particle velocity of air is the same as that of plate on the plate, we could easily redefine vibration equation using the velocity potential. We calculated the natural frequencies of plate using orthogonal polynomial functions which satisfy the boundary conditions in the Rayleigh-Ritz method. For the change of vibration characteristics, the effect of sound-structure interaction is more dominant than that of cut-out size.

A Study on Reduction of Sound Noise Induced by Disk Rotation in Optical Disk Drives (광 디스크 드라이브의 공력소음 감소에 관한 연구)

  • 송인상;박건순;최학현;김수경;이승엽
    • Journal of KSNVE
    • /
    • v.9 no.4
    • /
    • pp.693-702
    • /
    • 1999
  • We study the characteristics of airflow and sound noise induced by disk rotation in optical disk drives. The characteristics of airflow around a rotating disk surrounded by various tray structures are numerically investigated using a commercial CFD program and then compared with experimental results. Sound pressure and intensity caused by the fluid-structure interactions in the CD/DVD-ROM drive are measured, and the effect of the ariflow on the sound noise and disk vibration is discussed. In order to reduce airflow-induced noise and vibration around the rotating disk, tray geometry is modified. Both numerical and experimental studies implemented with different tray models show that the improved tray model alters the characteristics of the disk-induced airflow, causing the reduction of the airflow-induced sound level.

  • PDF

The Verification on Effect of Sound Absorption Tunnel for Elevated Railway (고가철교 방음터널 효과검증)

  • Kim, Hyung-Doo
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.17 no.3
    • /
    • pp.122-127
    • /
    • 2008
  • The source of wayside noise for the train are the aerodynamic noise, wheel/rail noise, and power unit noise. The major source of railway noise is the wheel/rail noise caused by the interaction between the wheels and rails. The Structure borne noise is mainly a low frequency problem. The train noise and vibration nearby the elevated railway make one specific issue. The microphone array method is used to search sound radiation characteristics of elevated structure to predict the noise propagation from an elevated railway. In this paper, the train noise and structure borne noise by train are measured. From the results, we investigated the effect on the sound absorption tunnel for elevated railway.

The Physics of Sound (소리 물리학의 기본 개념)

  • Jin, Sung-Min
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
    • /
    • v.22 no.2
    • /
    • pp.99-102
    • /
    • 2011
  • The laws of physics that govern actions of all moving bodies apply to sound. Because sound and all acoustic conditions consistently behave as described by the law of physics, we are able to predict and analyze the nature of a sound and its interaction. A fundamental understanding of the nature of the sound and terms used to describe it is essential to comprehend the language of otolaryngologists, audiologists, music acousticians, and engineers. Moreover, studying the basic physics of the sound helps one recognize complexities and potential pitfalls in measuring describing sound. We will talk about the structure of sound and its components, and we will see the various qualities of sound that make it interesting and useful to understand.

  • PDF

Reduction of radiated noise by eigen-property control (구조물의 고유특성 제어를 통한 방사소음 저감)

  • Choi, Sung-Hoon
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.658-663
    • /
    • 2004
  • The interaction between a vibrating structure and a surrounding acoustic medium determines the acoustic power propagating into the far-field. A straightforward method to reduce the radiated power is to reduce the vibration of the structure. However it is more efficient to control the modes of the structure separately since each vibration mode of the structure has different radiation efficiency. An efficient method to reduce the sound radiation in the low frequency region is proposed by reducing the radiation efficiency of the structure.

  • PDF

Flow Noise Source of Rotating Cylinder in a Cavity Structure (공동구조내 회전하는 실린더의 유동소음원 해석)

  • Park, Kye-Chan;Lee, Seungbae
    • 유체기계공업학회:학술대회논문집
    • /
    • /
    • pp.629-634
    • /
    • 2004
  • Cavities are inevitable structures in automobile configuration. The flow-induced noise is generated from the wheel housing section by the interaction between a rotating wheel and the unsteady flows in the cavity. In this research the wheel housing was assumed by a rectangular cavity for simplification. We measured the radiated sound from the 2-D cavity without cylinder and from the rotating cylinder in the cavity by using the sound source localization method with an acoustic mirror system. In the 2-D cavity case of low Mach number(Ma=0.029), the sound sources were found to be located near the leading edge of cavity due to the shear layer instabilities. Comparing the cases of the rotating and the non-rotating cylinder, it is observed that the sound Pressure levels around the rotating cylinder in the cavity increased and the main acoustic sources were located at the rear section of the rotating wheel.

  • PDF

Evaluation of Bolt-Loosening Joints of Truss Structure Through Sound Pressure Measurement (음압계측을 통한 트러스 구조물의 볼트 풀림 접합부 평가)

  • Cho, Dong-Ho;Eun, Hee-Chang
    • Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
    • /
    • v.11 no.2
    • /
    • pp.149-154
    • /
    • 2017
  • Vibration and acoustics travel through structure under the action of impact force at a position on the structure. The acoustic detection system comprises a microphone to capture the acoustic signatures of the vibrations. This work identifies the bolt-loosening joints to be used in truss structure using impact-acoustics approach. This work is originated from the observation that the sound pressure is deeply affected by the interaction between plates connected by bolts. The damage in the bolt joint can be detected based on the experimental data collected from impact hammer test using a microphone. It is observed that the bolt-loosening is appeared by the reduction of the resonance frequency due to the stiffness deterioration.

Sound Improvement of Violin Playing Robot Applying Auditory Feedback

  • Jo, Wonse;Yura, Jargalbaatar;Kim, Donghan
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.6
    • /
    • pp.2378-2387
    • /
    • 2017
  • Violinists learn to make better sounds by hearing and evaluating their own playing though numerous practice. This study proposes a new method of auditory feedback, which mimics this violinists' step and verifies its efficiency using experiments. Making the desired sound quality of a violin is difficult without auditory feedback even though an expert violinist plays. An algorithm for controlling a robot arm of violin playing robot is determined based on correlations with bowing speed, bowing force, and sound point that determine the sound quality of a violin. The bowing speed is estimated by the control command of the robot arm, where the bowing force and the sound point are recognized by using a two-axis load cell and a photo interrupter, respectively. To improve the sound quality of a violin playing robot, the sounds information is obtained by auditory feedback system applied Short Time Fourier Transform (STFT) to the sounds from a violin. This study suggests Gaussian-Harmonic-Quality (GHQ) uses sounds' clarity, accuracy, and harmonic structure in order to decide sound quality, objectively. Through the experiments, the auditory feedback system improved the performance quality by the robot accordingly, changing the bowing speed, bowing force, and sound point and determining the quality of robot sounds by GHQ sound quality evaluation system.

The Verification on Effect of Sound Absorption Tunnel for Elevated Railway in Cholla Line (전라선 고가교 방음터널 효과검증)

  • Kim, Byoung-Sam;Lee, Tae-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.667-672
    • /
    • 2007
  • The source of wayside noise for the train are the aerodynamic noise, wheel/rail noise, and power unit noise. The major source of railway noise is the wheel/rail noise caused by the interaction between the wheels and rails. The Structure borne noise is mainly a low frequency problem. The train noise and vibration nearby the elevated railway make one specific issue. In this paper, the train noise and structure borne noise by train are measured. From the results, we investigated the effect on the sound absorption tunnel for elevated railway.

  • PDF