• Title/Summary/Keyword: Sysnoise

Search Result 53, Processing Time 0.021 seconds

Design Sensitivity Analysis of Zwicker's Loudness Using Adjoint Variable Method (보조변수법을 이용한 Zwicker 라우드니스의 설계민감도)

  • Wang, Se-Myung;Kwon, Dae-Il;Kim, Chaw-Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.1432-1436
    • /
    • 2006
  • Feasibility of optimizing Zwicker's loudness has been shown by using MSC/NASTRAN, SYSNOISE, and a semi-analytical design sensitivity by Wang and Kang. Design sensitivity analysis of Zwicker's loudness is developed by using ANSYS, COMET, and an adjoint variable method in order to reduce computation. A numerical example shows significant reduction of computation time for design sensitivity analysis.

  • PDF

Calculation of transmission loss design values of a high speed train wall by acoustic analysis of exterior sound field (외부음장해석에 의한 고속전철 벽면에서의 투과손실 목표치 계산)

  • 김관주;유남식
    • Proceedings of the KSR Conference
    • /
    • 1998.05a
    • /
    • pp.249-256
    • /
    • 1998
  • Design target values of transmission loss in a high-speed train wall are suggested by calculating the difference between interior and exterior noise levels of it. Exterior noise level distribution on the boundary of train wall is calculated by Sysnoise, with sound source input prepared by experiments. Two kinds of exterior sound sources are considered, the rolling noise of train wheels on the rail and the aerodynamic noise from the pantograph. Interior noise level is provided by high-speed design target. Transmission loss characteristics according to the frequency band are examined.

  • PDF

THE DESIGN OF COMPRESSOR MUFFLER (압축기 머플러의 설계)

  • 박성근;윤해강;조성욱;임금식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1993.10a
    • /
    • pp.107-111
    • /
    • 1993
  • 본 논문에서는, 특히 고효율에 따른 소음 증가문제를 해결하기 위해 실험계획법을 이용한 머플러를 설계하였고, 설계단계에서부터 시뮬레이션 검증을 통해 효율을 고려한 저소음 머플러 설계가 가능하도록 머플러의 형상을 유한요소법에 의해 모델링한 후에, 소음해석 PACKAGE인 SYSNOISE를 이용하여 전달손실(TRANSMISSON LOSS) 해석을 해석하였고, 유동해석 PACKAGE인 PHONEMICS를 이용하여 압력손실을 최소화함으로써, 효율 및 소음측면에서 기존머플러보다도 더 우수한 머플러를 설계할 수 있는 PROCEDURE를 개발하였다. 이에 따라 차후 머플러내의 냉매유동특성과 소음특성을 동시에 고려한 머플러가 설계가능하리라 생각한다.

  • PDF

Resonance Condition of the Resonance Cavity and Air Gap in the Sacred Bell of the Great King Seongdeok (성덕대왕신종의 명동과 간극의 공명조건)

  • Kim, Seock-Hyun;Jeong, Won-Tae;Kang, Yun-June
    • The Journal of the Acoustical Society of Korea
    • /
    • v.30 no.4
    • /
    • pp.223-230
    • /
    • 2011
  • Korean bell is hung with some air gap between the bell bottom and the ground. In addition, it has a peculiar acoustic element, so called resonance cavity below the bell. A proper design of the air gap and cavity size dramatically amplifies the bell sound by resonance effect. Bell interior cavity, air gap and resonance cavity consist of an acoustic cavity system. When the acoustic cavity frequency coincides with the natural frequency of the bell body, the frequency component is significantly amplified. On the Sacred Bell of the Great King Seongdeok, this study proposes a resonance condition of the cavity system considering air gap effect for the first time. With the exact dimension of the bell, boundary element analysis is performed using SYSNOISE. Finally, this study reveals how the temperature in season influences the resonance condition and proposes a concept of variable type resonance cavity. By using the variable type resonance cavity, the cavity size is controlled on site and exact resonance is available regardless of temperature difference in season.

Design of a Variable Resonator for the Sacred Bell of the Great King Seongdeok (성덕대왕신종을 위한 가변형 명동의 설계)

  • Kim, Seock-Hyun;Jeong, Won-Tae;Kang, Yun-June
    • The Journal of the Acoustical Society of Korea
    • /
    • v.31 no.5
    • /
    • pp.288-297
    • /
    • 2012
  • This study proposes a design model of the variable type resonator which corrects the temperature variance according to the season, in order to maximize the resonance effect in the Sacred bell of the Great King Seongdeok. In the bell, the 1st natural frequency (64 Hz) and the 2nd natural frequency (168 Hz) are the most important partial tones. Resonance conditions of the two components are determined for the internal acoustic cavity system, which consists of bell body cavity, gap and the resonator. Acoustic frequency response characteristics of the internal cavity are determined by the boundary element analysis using SYSNOISE. As an external factor, temperature variance according to the season largely influences the resonance condition and the length of the resonator should be controlled to maximize the resonance effect. As a measure, this study proposes a design model of the variable type resonator for the Sacred Bell of the Great King Seongdeok, which can control the length at the belfry according to the season.

The Development of a design approach for reducing intake noise of vehicle (자동차 흡기소음저감을 위한 설게기법에 관한 연구)

  • 오재응;한광희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1996.04a
    • /
    • pp.41-46
    • /
    • 1996
  • The engine intake system noise has been recognized as a problem for many years. Acoustic design of intake system has traditionally been a trial and error process. This has resulted in the development of computer simulation program for a acoustic analysis and acoustic modeling. In this study, we developed the program based on the transfer matrix method which analyze and predict the performance of a intake noise. The program was verified by experiments on a real intake system. By using of the simulation program, we analyzed acoustic characteristics and, made proposals of improvement to reduce the intake noise and was verified by the SYSNOISE software.

  • PDF

The Analysis of Transmission Characteristics of Closed Structure with Internal Source Using FEM/BEM (유한.경계요소법을 이용한 내부음원을 갖는 닫힌 구조물의 차음 특성 해석)

  • Won, Sung-Gyu;Jung, Weui-Bong;Seo, Yeung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2005.05a
    • /
    • pp.318-321
    • /
    • 2005
  • In vibro-acoustic analysis, the commercial CAE tools, such as SYSNOISE, is usually used to take into account of the coupled effects of fluid acoustics and structural vibration. The acoustic field can be solved by either FEM or BEM, while the vibration field is usually solved by FEM. The interior or exterior acoustic problems with the coupled effects of the structural boundary could be solved by the commercial tools. The commercial tools, however, could not solve the problems in case that both the interior and exterior acoustic field is coupled with the structural boundary. In this paper, a realistic method based on FEM/BEM coupling scheme is presented to analyze the acoustic radiation from the internal source in a chamber to external acoustic field through elastic structural boundary. Several numerical examples are implemented to validate the developed program.

  • PDF

Acoustic Analysis of the Cavity in Rotary Compressor (로터리 압축기 내부의 소음해석)

  • 정의봉;김봉준;김재호
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.24 no.2
    • /
    • pp.97-103
    • /
    • 2000
  • Gas pulsation discharged from the cylinder causes noise in the rotary compressor. Mufflers are usually used to reduce the noise generated by the gas pulsation. The muffler has been designed to maximize the acoustic transmission loss of the muffler. The gas which went through muffler is discharged to the cavity in compressor. Thus, the acoustic characteristics of cavity should be taken into account in muffler design. In this paper, the program for the acoustic substructure synthesis method is developed. This program can be interfaced with SYSNOISE which is commercial acoustic package. Several types of mufflers designed to have the better acoustic performance are suggested in this work and compared with the existing commerical muffler in the compressor. The acoustic performance of mufflers taking into consideration of the cavity in the compressor is also carried out by the developed program.

  • PDF

Noise and Vibration Analysis of a cylindrical shell by controlling ER mount (ER 마운트 제어에 의한 원통쉘의 진동소음 해석)

  • Jung, Woo-Jin;Jung, Weui-Bong;Seo, Young-Soo;Cho, Hyun-Dong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2002.11b
    • /
    • pp.459-463
    • /
    • 2002
  • ER mount can be used instead of rubber mount in cylindrical shell to improve the vibration and noise performance. The noise radiated by cylindrical shell will be reduced by reducing the force transmitted to the cylindrical shell through ER mount. In this paper LQ control theory is used to reduce the transmitted force to the cylindrical shell. The finite element method of cylindrical shell is formulated by NASTRAN and its vibrating shape is calculated in frequency domain. The noise radiated from the cylindrical shell is calculated by the use of SYSNOISE, the boundary element CAE tool. The vibration of the cylindrical shell and radiated acoustic pressure is compared in case of both controlled and uncontrolled ER mount.

  • PDF

Interior Noise Reduction of a Passenger Car using Panel Contribution Analysis (패널 기여도 분석에 의한 승용차의 실내 소음 저감)

  • 이두호;김태정
    • Journal of KSNVE
    • /
    • v.9 no.4
    • /
    • pp.785-794
    • /
    • 1999
  • The panel contribution analysis to reduce interior booming noise of a passenger car is carried out using both experimental method and numerical one. The accelerations of panels are measured on the outer surface of car body during operation. The acoustic characteristic of cavity is represented by two different ways. One is the acoustic transfer function obtained by experiment with reciprocal manner. The other is the boundary element model and numerical results of the model are calculated using SYSNOISE. The results from numerical method show more good agreement with measured sound pressure levels than the experimental one. Contributions of panels for interior noise are ranked and structure of the car is reinforced according to the results, which shows that the panel contribution analysis is a powerful tool to lessen structure-borne noise of passenger vehicle.

  • PDF