• 한국철도학회논문집
• /
• 제14권1호
• /
• pp.19-23
• /
• 2011

고속철도 차량의 고속화, 경량화와 더불어 승객의 실내 소음을 줄이기 위한 많은 연구가 진행되고 있다. 고속철도 차량의 실내 소음을 줄이는 방법으로 차량 구조물의 차음 성능을 향상시키는 연구가 중요시 되고 있으나 투과손실 연구는 많은 경제적 비용이 요구된다. 따라서 본 연구에서는 소형 잔향실을 이용하여 고속철도 차량의 투과손실을 측정할 수 있는 방법을 연구 하였다. 연구 결과 소형 잔향실을 이용한 차음성능 연구가 대형 잔향공간을 이용한 투과손실 결과 대비 신뢰성 있는 결과를 도출 하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2011년도 추계학술대회 논문집
• /
• pp.92-95
• /
• 2011

The walls of modern train cars are required to have higher transmission loss since modern train have had high speed and light weight. The method based on Reverberation Chamber like KS F 2808 could be used to measure transmission loss. However, this method has difficulty in that constrained Standard of it requires extremely large facilities. Recently, the method based on Scale Reverberation Chamber is used as an alternative to Reverberation Chamber. The method of Scale Reverberation Chamber is known to be small and economical but it provides standing wave that directly influences measurement error. Therefore, this research is focus on predicting standing waves based on method of FFM and reducing measurement error by changing shape of chamber.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 춘계학술대회논문집
• /
• pp.797-801
• /
• 2003

The Statistical Energy Analysis is based on the power flow and the energy conservation between sub-systems, which enable the prediction of acoustic and structural vibration behavior in mid-high frequency ranges. This paper discusses the identification of SEA coupling loss factor parameters from experimental measurements of small reverberation chamber sound pressure levels and structural accelerations. As structural subsystems, steel plates with and without damping treatment are considered. Calculated CLFs were verified by both transmission loss values for air-borne CLF case and running SEA commercial software As a result, CLFs have shown a good agreement with those computed by software. Acoustical behavior of air-borne noise and structure-borne noise has been examined. which shows reasonable results, too.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2010년도 추계학술대회 논문집
• /
• pp.302-307
• /
• 2010

Development of light-weight high speed train (HST) based on distributed motor control with the top speed of 350 km/hr has engendered a need for abatement of the interior noise of the train cabin. The development of noise abatement measures is crucial at the design stage of the train car since the noise transmission characteristics of the car structure directly influences the cabin interior noise. Since the transmission loss measurement using the entire car structure is often not feasible, especially at the initial stages of the train development, investigation of transmission characteristics using small-scale reverberation chamber can furnish useful alternative source of predicting the noise level. In the present study, white noise is generated at source and transmission loss estimated by performing measurement of a specimen in a scaled reverberation chamber. Comparison of measured values with the previously derived numerical values show good agreement in the overall trend but appreciable quantitative differences still remain.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.960-965
• /
• 2014

Transmission loss of specimen is calculated by measuring energy of incident and transmission and using reverberant room of large size. But normal measurement of transmission loss has trouble because it is actually demanded that large area and specimen of certain size is satisfied with condition of diffused sound field. Especially, in case of mechanical component, interested frequency band is mid-frequency band between 500 ~ 2k Hz, and it is used to be available to minimize a reverberation chamber under conditions satisfying acoustic one because production of specimen for transmission loss measurement has limit. But, as in semi-reverberation room, it is difficult to satisfy condition of diffuse sound field and modification factor is applied to complement that. Correction factor when measuring transmission loss using semi-reverberation chamber is required accuracy because it works as main factor determining reliability of reuslts on transmission loss. In this study, it is analyzed that an effect on correction factor based on varying materials and sizes of specimens in order to deduction of it. Also It is confirmed that applied by elicited correction factor with actual railway vehicle's floor has reliability.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.579-580
• /
• 2008

• 대한전자공학회논문지TC
• /
• 제45권8호
• /
• pp.121-127
• /
• 2008

본 논문은 원통형 확산기를 사용한 전자파 잔향실내의 전기장 분포에 관하여 다루었다. $1{\sim}3$ GHz 주파수 대역의 QRD(Quadratic Residue Diffuser)와 원통형 확산기(Cylindrical Diffuser)를 설계 후 각각의 전기장 분포 특성을 비교하였다. 전기장 분포 특성 및 전기장 균일도를 조사하기 위해 FDTD(Finite-Difference Time-Domain) 수치 해석 방법을 사용하였으며, 2 GHz에서 수치해석 결과 원통형 확산기를 사용하였을 경우 기존의 QRD를 사용한 경우에 비하여 표준편차와 공차는 각각 0.11 dB, 0.43 dB 개선되었고, 전기장 세기는 QRD의 36.6 dBmV/m보다 높은 43.2 dBmV/m로 나타났으며, 편파 특성면에서도 QRD보다 개선되었음을 확인 할 수 있었다. 따라서 원통형 확산기를 사용한 전자파 잔향실이 소형 전자기기의 전자파 장해 및 복사 내성 측정을 위한 대용시험 시설로 사용될 수 있음을 확인하였다.