A program was written that calculates the contact point and rolling radius difference by considering the lateral displacement of the wheelset with respect to the rail. The characteristics of the equivalent conicity were analyzed according to the distribution characteristics of wheelset lateral displacement using the calculated rolling radius difference. The standard deviation value representing the characteristics of the wheelset lateral movement should be appropriately applied considering the range of the lateral wheelset displacement. If a small standard deviation value is applied when the lateral displacement increases during actual driving condition, the equivalent conicity could be underestimated, which may cause a problem in determining a reliable stability of the railway vehicle.

When a train enters a tunnel, a pressure wave is generated. This pressure wave propagates in the tunnel and emits as micro pressure wave at the opposite tunnel exit. This pressure wave could appear as a sound pulse in a particular environment and cause hazardous effects on the environment near the tunnel exit. When planning tunnels, it is necessary to take appropriate measures to reduce the magnitude of the micro pressure wave. In this study, we investigated the existing micro pressure wave management standards and studied the signal processing method and the sound evaluation method which were used in setting the appropriate management standard for the evaluation of the micro pressure wave.

One of the important advantages of Thermosonics is that it can be applied to complex structures such as a turbine blade as a convenient and quick screening test method. For a reliable thermosonic test, the vibrational characteristics of the system comprising the tested structure and the clamp at ultrasonic frequency range should be identified. Therefore, this study presented the analysis results of frequency response functions and mode shapes of the turbine blade and clamp system and investigate the possibility of the reliable excitation system for the thermosonic test.

IR camera has been used widely for the temperature measurement and fault detection of the moving bodies and rotating bodies. The high-speed performance of the IR camera and a reliable thermal analysis method are required for the condition monitoring of the railway vehicle running at high speed. The effective fault detection method using a thermal image analysis could make a real time monitoring of the high speed train possible. Therefore the investigation of the performance of the thermal image analysis method was performed to find the effective thermal image data analysis method. The results suggested that the comparison of the characteristics of the temperatures obtained at different conditions and a continuous temperature subtraction method could be used as a useful analysis method for detecting abnormal temperature condition and histogram equalization could also help to enhance the fault detectability by increasing the contrast of the thermal image

본 연구에서는 서모소닉 시험을 위한 실용적이고 편리한 PZT 가진 시스템을 구축하고 그 특성을 평가하고자 하였다. PZT 가진기의 성능 평가 및 가진기와 시험체와의 다양한 연결방법의 효과에 대하여 평가하기 위한 실험 을 수행하였다. 실험은 서로 다른 두께를 가진 금속 플레이트를 이용하여 수행되었다. 본 논문에는 실험 장치 및 다양한 연결방법의 성능 시험 결과가 소개되었다. 실험 결과 가진기의 공진 주파수 근처에서 작은 입력 전압과 작은 힘을 이용하여 큰 변형률을 가진 다수의 모드를 가진 할 수 있었고 이 결과는 가진 중에 비선형 진동의 발 생 없이 서모소닉 시험을 위해 충분한 변형률을 얻을 수 있는 가능성을 보여준다. 결과적으로 결함 검출을 위해 작은 크기의 변형률이 필요한 시험체의 경우 작은 PZT 가진기가 간편하고 신뢰성 있는 가진 시스템을 제공 할 수 있다는 가능성을 보여주었다.