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서태건(Seo Taegun),김석현(Kim Seockhyun),김정태(Kim Jeong-tae),송달호(Song Dalho) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월
Recently, aluminium extruded panel is widely used in a high speed train for increasing bending stiffness and weight reduction. This aluminium extruded panel shows the largest contribution in the sound transmission loss (TL) of the floor and side wall. However, comparing with the flat panel having the same weight, TL of the aluminium extruded panel falls remarkably around the local resonance frequency, which is determined by the dimension of the core structure. In this study, we try to change the local resonance frequency by modifying the core structure. Increasing or decreasing the thickness, angle and span in the core, change of the local resonance frequency and change of the overall natural frequency are investigated by finite element analysis, and effect of local resonance on TL is examined. The purpose of the study is to design more effective core structure for the sound insulation performance of the aluminium extruded panel.
서태건(Taegun Seo),김석현(Seockhyun Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In a Korean tilting train, honeycomb composite panel is used for high speed and light weight. Side wall of the tilting train consists of the aluminum honeycomb coated with carbon fiber reinforced epoxy skin as the main structure. In this study, based on ASTM E2249-02, we measure the intensity sound transmission loss (TL) of the honeycomb composite panel. Using mass law deviation (MLD), we estimate the sound insulation performance of the honeycomb composite panels in aspect of weight and feel out the feasibility of the substitution for the conventional corrugated steel panel.
서태건(Taegun Seo),김석현(Seockhyun Kim),김정태(Jeong-tae Kim),송달호(Dalho Song) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7
Aluminium extruded panel is the most important element for sound insulation in a express train. However, comparing with the flat plate with the same weight, the extruded panel shows remarkably low sound transmission loss above the 1st local resonance frequency, which is determined by the dimension of the core structure. Preceding study showed the possibility of the improvement of sound insulation performance by properly designing the core dimension. By the proper core design, local resonance frequency shifts to higher frequency region without any reduction of bending or torsional strength and without any weight increase. Based upon this result, this study investigates in detail the design modification of the core structure of the aluminium extruded panel used in a express train under development, in aspect of sound insulation. Design result is compared with those of other developed models.
서태건(Taegun Seo),김석현(Seokhyun Kim),김정태(Jung-tae Kim),김재철(Jaecheol Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
In a railway vehicle, corrugated steel panel is widely used for the floor structure because of its high bending stiffness and light weight. However, this panel shows lower sound insulation performance than that of the plate with the same weight. Especially, in a particular frequency region, transmission loss (TL) rapidly decreases and it results in the deterioration of TL of the overall floor structure. This study identifies that the remarkable drop in TL is caused from the local resonance of the periodic corrugated structure. The reason of the TL drop is investigated by experiment and finite element analysis. In addition, improvement effect of TL by the design modification of the corrugation is estimated by experiment. The purpose of the study is to provide the practical information for the improvement of the sound insulation performance of the corrugated steel.
김석현(Seockhyun Kim),서태건(Taegun Seo) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.12
한국형 틸팅열차에는 고속화와 경량화를 위하여 허니콤 복합재가 처음으로 사용된다. 틸팅열차의 측벽은 탄소섬유강화 에폭시층과 접착된 알미늄 허니콤 및 노멕스 허니콤 판재를 주 요소로, 유리면이 적층된 복합 적층재이다. 본 연구에서는 ASTM E2249-02에 근거하여 알미늄 및 노멕스 허니콤 복합 적층재의 층별 인텐시티 투과손실을 측정한다. 질량법칙편차를 이용하여 허니콤 복합재의 중량 대비 차음 성능을 평가하고, 차음 측면에서 알미늄 허니콤 복합재가 기존의 주름강판을 대체할 수 있는지의 가능성을 검토한다. 본 연구를 통하여 얻은 허니콤 복합 적층재의 차음성능 자료는 향후 틸팅 열차의 실내소음 대책 수립에 활용될 것이다. In Korean tilting trains, honeycomb composite panels are used for high speed and light weight. The side wall of a tilting train consists of an aluminum honeycomb coated with carbon-fiber-reinforced epoxy skin and a nomex honeycomb panel as the main structure, with glass wool inserted between the panels. In this study, based on ASTM E2249-02, we measure the intensity sound transmission loss (TL) of the honeycomb composite panels. Using mass law deviation (MLD), we estimate the sound insulation performance of the honeycomb composite panels in terms of their weight and explore the feasibility of substituting a conventional corrugated steel panel. The transmission-loss data of the honeycomb composite panels obtained in the study will be used to establish noise-reduction measures for train compartments.
김석현(Seockhyun Kim),서태건(Taegun Seo),김정태(Jeong-tae Kim),송달호(Dalho Song) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.5
알미늄 압출재는 고속열차의 경량화를 위하여 기존의 주름강판을 대체하여 널리 사용된다. 알미늄 압출재는 고속열차 적층재 가운데 가장 큰 차음 기여도를 보이나, 동일한 중량의 평판과 비교할 때, 국부공진 주파수 대역에서 투과손실이 크게 떨어진다. 이 연구에서는 차세대 400㎞/h급 고속철도 차량용 알미늄 압출재를 대상으로 차음 문제를 검토하고, 차음성능의 향상 방안을 제시한다. 코어 구조를 변경시켜 국부공진 대역을 높이고, 우레탄 폼을 코어에 충진시킬 때의 차음성능 향상효과를 실험적으로 확인한다. 최종적으로 제시된 방법이 바닥 적층재의 총 투과손실을 어느 정도 개선시키는가를 평가한다. Aluminum extruded panels are widely used instead of corrugated steel panels for weight reduction in high-speed trains. Of the layers in the train body, it makes the largest contribution to the sound insulation. However, compared with that of a flat panel with the same weight, the TL of the aluminum extruded panel is remarkably lower in the local resonance frequency band. We study aluminum extruded panels for next-generation 400-㎞/h trains. We investigate the problem of sound insulation and propose a practical method to improve the sound-insulation performance. The local resonance frequency region is increased by a modification of the core structure, and urethane foam is placed in the core. The effect on the sound insulation is verified by experiments. Finally, the improvement for the entire sound-transmission loss is estimated for the layered floor panels of express trains.