• Title, Summary, Keyword: Interior noise

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Tools to Understand Interior Noise due to Road Excitation in Cars (노면 가진에 의한 실내 소음 해석 방법)

  • Taewon Kang;Sang-Gyu Lim
    • Journal of KSNVE
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    • v.8 no.6
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    • pp.1158-1165
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    • 1998
  • Low frequency interior noise in cars is mainly due to structure-borne excitations which are related with road excitation and component vibrations such as suspension and engine mounts. In order to analyze the annoying interior noise. a technique (Transfer Path Analysis) is introduced to find a noise source and the path of that noise. In this study, TPA is reviewed theoretically and applied to investigate the case when the low frequency interior noise at front seat due to road excitations needs to be optimized. The subjective and objective appraisal was performed under the conditions that a testing vehicle traveled on asphalt at 30 km/h. so that the low frequency to be eliminated was detected. The related vibration and noise data for TPA were measured on running and static vehicle. The results reveal that the noise contribution along the z-direction of trailing arm is prominent to low frequency interior noise.

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Interior Noise Reduction of Wheel Loader Using Transfer Path Analysis and Panel Contribution Analysis (전달 경로 분석과 패널 기여도 분석을 이용한 휠로더의 실내소음 저감에 관한 연구)

  • Kim, Bo-Yong;Shin, Chang-Woo;Jeong, Won-Tae;Park, Sung-Yong;Jang, Han-Kee;Kim, Seong-Jae;Kang, Yeong-June
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.8
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    • pp.805-815
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    • 2008
  • Transfer path analysis(TPA) and panel contribution analysis(PCA) have been used widely to reduce interior noise of mechanical systems. TPA enables us to decompose interior noise into air-borne and structure-borne noises and estimate the path contribution of noise sources. PCA is also used to identify the noise contribution of each sub-panel in vibro-acoustic systems. In this paper, TPA and PCA are applied to wheel loader, one of the heavy construction equipments. Firstly, TPA for air-borne noise is conducted to estimate the contribution of air-borne sources using pressure transfer function. Thereafter, TPA for structure -borne noise is employed to verify the results of air-borne source quantification through the synthesis of two results. Secondly, PCA is performed by both TPA using pressure transfer function between panels inside the cabin and boundry element method(BEM) for the cabin of wheel loader with various boundary conditions. As a results, it was found that TPA conducted by experiments and PCA accomplished by both experiments and BEM are very effective methods in analyzing the path and contribution of the noises for reducing an interior noise level in the wheel loader system.

The Experimental Study on the Correlation of the Interior Noise of a Driving Vehicle with Lateral Dynamic Stiffness of the Wheel (주행 중 실내소음과 Wheel의 Lateral Dynamic Stiffness와의 상관관계에 대한 시험적 연구)

  • Kim, Byung-Jin;Sa, Jung-Hwan;Park, Jin-Sung;Park, Hyun-Woo;Cho, Seong-Keun;Jeong, Heon Sul
    • Transactions of the KSME C: Technology and Innovation
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    • v.2 no.1
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    • pp.9-13
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    • 2014
  • Nowadays, among several reasons for customers to choose their own cars, NVH performance plays much important role. The concern for the car interior noise is increasing recently, because electric cars and hybrid cars generate less engine noise which was the main noise of traditional cars. According to oversea references, high Lateral Dynamic Stiffness (LDS) of vehicle wheels is described to reduce Structure Bone Noise (SBN) which is being generated while driving cars. However availablet test standards and test results are not enough, in this study the interior noise has been measured after attaching a same tyre to several wheels which has different Lateral Dynamic Stiffness. The test has verified that the interior noise differs depending on Lateral Dynamic Stiffness of wheels. As to this, the reduction of the interior noise can be possible with the optimal design of the wheel.

Active Noise Control of Closed Rectangular Cavity using the FXLMS Algorithms (FXLMS 알고리듬을 이용한 사각밀폐공간의 능동소음제어)

  • Ryu, Kyung-Wan;Hong, Chin-Suk;Jeong, Wei-Bong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.247-249
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    • 2009
  • This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to reduce interior noise globally. To obtain global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary speaker that produces a global reduction of the interior noise field. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary speaker should be located as close to the primary source as possible in order to obtain global reduction.

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Active Noise Control of a Closed Rectangular Cavity Using FXLMS Algorithms (FXLMS 알고리듬을 이용한 사각밀폐공간의 능동소음제어)

  • Ryu, Kyung-Wan;Hong, Chin-Suk;Shin, Chang-Joo;Jeong, Weui-Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.11
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    • pp.983-990
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    • 2011
  • This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to globally reduce the interior noise. To obtain the global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary source that produces a global reduction of the interior noise field using single channel control. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary source should be located as close to the primary source as possible in order to obtain the global reduction.

Analysis of the internal noise level according to the speed for the Korean High Speed Train (한국형 고속전철 개발열차의 차량별 속도에 따른 실내 소음 특성 분석)

  • Park Chun-Soo;Kim Ki-Hwan;Seo Sung-Il;Lee Tae-Hyung;Park Chan-Kyung
    • Proceedings of the KSR Conference
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    • pp.381-386
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    • 2004
  • In order to develop a high speed train, various conditions have been considered. Internal noise level of cabins is an important one. In this study, The specification of the interior noise level for KHST(Korean High Speed Train) has been adopted the same level of KTX-spec. In this paper, the interior noise levels of KHST are measured and analysed through the speed and other conditions. According to the speed, the level of internal noise(driver's room(PC2), motorized trailer(TM1) and trailer car(TT2)) is compared. The results of measuring data show that the interior noise levels of KHST are good. And noise levels of this paper are useful in the decision of noise specification.

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The capture of small variations in interior noise levels using PowerFLOW

  • Cyr, Stephane;Choi, Eui-Sung;Moron, Philippe;Senthooran, Siva
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.565-568
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    • 2014
  • Hyundai Motor Company is proposing the fourth evolution of their Hyundai Simplified Model as benchmark results for the validation of CFD codes in aeroacoustics and noise transmission to the interior of a cabin. The focus of this benchmark is on variations in noise level induced by small typical geometry changes that can be found in a car development program. This article presents the noise transmission results obtained with PowerFLOW in combination with a SEA model and shows that it is possible to capture small variations in noise level with a lattice Boltzmann method based code.

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A Study for Interior Noise Contribution of Support Material used in Railway Vehicle Floor (철도차량 부유상구조의 Floor support 재질이 차량 실내소음에 미치는 영향에 관한 연구)

  • Son, Byoung-Gu;Kim, Jong-Nyeun;Woo, Kwan-Je
    • Proceedings of the KSR Conference
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    • pp.1776-1781
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    • 2008
  • To reduce interior noise of running vehicles, a floating floor construction has been widely used in recent railway industry. Among the key factors of the floating floor design, dynamic stiffness is of most important in acoustical point of view. Sometimes hard rubber type supports have often been selected due to the other design constraints such as heavy load condition, durability of rubber element and its cost etc., even though it seems like the softer support, the better isolation of noise and vibration. In this paper two representative floor supports have been considered to evaluate their effectiveness in interior noise contribution: one is a soft rubber and another is a relatively hard one. From the measured dynamic stiffness of the specimens, equivalent stiffness of actual floating floor has been derived to use in the analytical models. Calculated air-borne and structure-borne noise insulation properties of the floating floors have been compared with experiments in prototype car. In full car model interior noise levels of running vehicles have been predicted to quantify the effectiveness of the two different floating support materials and verified through the measured inside noise levels of actual train as well. By comparison with difference of running noise levels two materials for floor support can be investigated quantitatively so that it could be applied in floating floor design.

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Study on the Evaluation of Sound Quality of a Vehicle Interior Noise (차량의 실내소음에 대한 음질평가 연구)

  • Lee, J.K.;Chai, J.B.;Jang, H.K.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.8
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    • pp.945-953
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    • 2005
  • The purpose of this paper is to develop a linear regression model for the sound quality index of vehicle Interior noise. For this, objective measurement data of the vehicles driving in acceleration was measured. On the basis of analysis, psychoacoustic parameters were extracted and subjective evaluation was performed by noise and vibration expert evaluators. For the subjective evaluation, the paired comparisons and the semantic differential methods were used to evaluate sound quality of vehicle interior noise. By the paired comparison which evaluate two pairs of vehicle interior noise, the preference was estimated. With the semantic differential and the factor analysis, it was evaluated words of two pairs which expressed appropriately the sense of evaluator about noise source. Therefore the characteristics of the sound qualify for the vehicle were differentiated. From the results of both the correlation analysis and the multiple factor regression analysis, the sound quality evaluation model for the sense of human hearing was derived and indexed.

Interior Noise and Low Frequency Noise Characteristics of Busan Metro Line 3 Noise (부산도시철도 3호선 실내소음 및 저주파 소음 특성)

  • Hong, Do-Kwan;Jeong, Jae-Boo;Jung, Seung-Wook;Gang, Hyun-Wook;Ahn, Chan-Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.11
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    • pp.1113-1120
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    • 2012
  • This paper deals with the analysis of interior noise and low frequency noise characteristic for the Busan citizens to use public transport, Busan Metro Line 3. The interior noise evaluation index, articulation index(AI) is evaluated the lower value about average 22 % in a whole range, this is difficult to have a conversation. Also, noise criteria(NC) curve is partially evaluated as NC-65 below 2000 Hz, space type is evaluated as factories. Another of interior noise evaluation index, preferred speech interference level(PSIL) is evaluated the upper value about average 66 dB(A) in a whole range, this is evaluated to be interrupted. In the case of low frequency noise(20~200 Hz), the measurement of low frequency noise is assessed largely beyond noise criteria of ISO 226. The low frequency noise should be reduced because low frequency noise affects on psychological stress and displeasure although low frequency noise is not recognized by auditory sense. The low frequency noise criteria and guideline will be enacted from now on in Korea.