Magnetic Barkhausen noise (MBN) can be used to potentially detect fatigue, creep, stress, and hardness in ferromagnetic materials. Recently, non-destructive measurement equipment using MBN has been developed to measure the residual stress of railway rails in Korea. MBN has different characteristics depending on the type of ferromagnetic steel and residual stress. In this study, MBN signal characteristics based on the stress change of SS275 steel are experimentally analyzed using the developed MBN equipment. The results of this study can be used as basic data for estimating the residual stress of SS275 steel in the future.

The Sliding Track Panel (STP) System is a method for installing Continuous Welded Rail (CWR) in a long-span ballastless track bridge, such as a truss bridge. The STP system aims to reduce additional stress generated on the rail due to track-bridge interactions. However, as the STP system eliminates longitudinal resistance by eliminating the sleeper fastener device installed on the existing ballastless track bridge, there is no buckling stability in the vertical and lateral directions. Therefore, a plan was devised to install a lateral reinforcement plate to increase the lateral resistance. This paper investigated the effect of increasing the lateral resistance of the reinforcing plate through a field test to determine the lateral resistance performance of the track panel.

This study aims to optimize the cochlea-inspired artificial filter bank (CAFB) using El-Centro seismic waveforms and test its performance through a shaking table test on a two-span bridge model. In the process of optimizing the CAFB, El-Centro seismic waveforms were used for the purpose of evaluating how they would affect the optimizing process. Next, the optimized CAFB was embedded in the developed wireless-based intelligent data acquisition (IDAQ) system to enable response measurement in real-time. For its performance evaluation to obtain a seismic response in real-time using the optimized CAFB, a two-span bridge (model structures) was installed in a large shaking table, and a seismic response experiment was carried out on it with El-Centro seismic waveforms. The CAFB optimized in this experiment was able to obtain the seismic response in real-time by compressing it using the embedded wireless-based IDAQ system while the obtained compressed signals were compared with the original signal (un-compressed signal). The results of the experiment showed that the compressed signals were superior to the raw signal in response performance, as well as in data compression effect. They also proved that the CAFB was able to compress response signals effectively in real-time even under seismic conditions. Therefore, this paper established that the CAFB optimized by being embedded in the wireless-based IDAQ system was an economical and efficient data compression sensing technology for measuring and monitoring the seismic response in real-time from structures based on the wireless sensor networks (WSNs).

Recently, the concept of a Sliding Track Panel (STP) system, which allows the bridge to slide in the longitudinal direction, has been proposed for continuous welded rail method laid on long span non-ballast bridges, such as truss railway bridges. The performance of the STP system is determined based on the ability to prevent the lateral buckling of STP. This study attempts to derive the optimum interval distance and required stiffness of the lateral support member to be installed in the STP system through buckling analysis. According to the analysis, the interval distance of lateral support member, which satisfies the strength of STP, is less than 2.8 m and the rigidity is more than 800 N/mm.

다양한 분야에서 충돌에 관련된 연구가 활발히 이루어지고 있고, 특히 자동차 분야에서는 오랫동안 연구를 진행하였다. 도로상에 설치되는 방호벽을 설계하기 위해 자동차와 방호벽 간의 충돌시험을 통해 방호벽에 발생하는 충돌 하중을 구하였다. 하지만 이렇게 시험을 통해 구한 값은 매우 복잡한 고주파 데이터와 노이즈를 포함하게 되어 적절한 데이터 필터링 과정이 필요한 실정이다. 외국에서는 충돌 시험 시 획득한 데이터를 원활하게 분석하기 위하여 필터링 방법에 대한 연구를 지속적으로 진행하여 왔고 기준을 마련하여 적용하고 있다. 국내의 자동차 분야에서는 미국의 기준을 사용하고 있으나 열차 충돌에 대한 기준은 없는 실정이다. 본 논문에서는 열차 충돌에 대한 필터링을 기준을 정립하기 위한 선행 연구를 수행하였다.

교량 상에 자갈궤도가 부설될 경우 온도와 차량하중에 의해 상대변위가 발생하며 이를 통해 레일부가응력이 발생하게 된다. 이러한 레일부가응력은 자갈궤도의 종방향 저항력에 많은 영향을 받는다. 현재의 자갈궤도 종저항력은 토노반 상의 자갈궤도 실험 결과를 토대로 지침에 적용이 되어있는 실정이다. 본 연구에서는 교량 상에 자갈궤도를 부설한 실대형 실험체를 제작하여 수직하중 비재하와 재하시의 궤도 종저항력을 측정하였으며, 이를 통해 종방향 저항력 특성을 분석하였다.

This paper attempts to develop a wireless feedback control system as a primary step eventually toward a bio-inspired structure system where inanimate structure behaves like a life form autonomously. It is a standalone wireless control system which is supposed to measure externally caused structural responses, analyze structural state from acquired data, and take its own action on the basis of the analysis with an embedded logic. For an experimental examination of its effectiveness, we applied it on a model of two-span bridge and performed a wireless control test. Experimental tests have been conducted for comparison on both the wireless and the wired system under the conditions of Un-control, Passive-off, Passive-on, and Lyapunov control algorithm. By proving the congruence of the test result of the wireless feedback control system with the wired control system, its control performance was proven to be effective. Besides, it was found to be economical in energy consumption and also autonomous by means of a command algorithm embedded into it, which proves its basic capacity as a bio-inspired system. Keywords—Structural vibration control, wireless system, MR damper, feedback control, embedded system.

예기치 못한 탈선사고 발생 시 탈선열차에 대한 피해를 최소화하기 위한 대비로 탈선방지가드레일이나 방호벽 등의 물리적인 시설물을 설치하고 있다. 현재 국내의 방호벽의 경우 고속철도 도입 시 유럽 관행에 따라 도입하였으나, 이에 대한 설계하중 및 설치위치, 규격에 대한 기준 근거가 미약하고 정립 및 체계화되어 있지 않다. 또한, 탈선된 열차의 거동 특성에 대한 공학적 분석 및 방호시설 적용에 따른 실효성과 경제적 타당성 등을 입증할 수 있는 객관적인 자료가 전 세계적으로 미비한 실정이다. 이에 본 논문에서는 방호시설에 대한 효과입증, 방호 성능평가 기술 등을 확보하기 위한 선결과제로 국내 최초로 탈선된 열차의 거동 특성을 파악하기 위한 실대형 탈선/충돌 실험을 수행하였다. 실험차량은 주강대차를 이용하였고, 타고오름 탈선을 모사하여 탈선 이후 차륜과 레일, 체결장치, 침목 등 궤광 구성품과의 충돌거동을 분석하였다.

The continuous welded rails (CWR) installed on railway bridges should be checked for the effects of track-bridge interactions. In the case of a concrete track on a bridge, the longitudinal resistance of the track is determined by the longitudinal resistance of the rail fastening system, and the safety of track is assessed by using the longitudinal resistance given in KR C-08080 (track-bridge longitudinal interaction). However, a very conservative design is derived when using the longitudinal resistance values presented in the KR code. Therefore, a longitudinal resistance considering the type of fastening system actually installed should be proposed. In this study, the results of the laboratory tests of the rail fastening system were analyzed and the longitudinal resistance was determined to enable the economic and safe side design, reflecting the statistical characteristics of the resistance.