레일 波狀摩耗 測定시스템의 開發에 관한 硏究

Abstract

This study presents the development of a rail corrugation measurement system. The manual scan system, sensor, signal acquisition and evaluation software will be presented. The rail corrugation is measured by a linear variable differential transformer (LVDT) sensor and an optical camera for visualization of the rail surface conditions. The LVDT measurement base is on a skate which has length of 300 mm, triple times of the measurable maximum wavelength of the corrugation (100 mm). The LVDT signal is analyzed by fast Fourier transform (FFT) and short-time Fourier transform (STFT) to find the corrugation and distribution of wavelength. To observe the area of rail corrugation, optical camera is synchronized with the LVDT signal and stored optical images in data base. The scan speed and scan interval are 1.4 km/h and 1.317 mm, respectively. The system can operate during 2 hours and 20 minute by using a built-in battery without external power supply. In order to evaluate the effectiveness of the rail corrugation measurement system, rail specimens (50kgN type) with artificial rail corrugations and on-site test in the subway stations (Geumnamro 5-ga Station to Munhwajeondang Station, Gwangju, Korea) have been tested. On the artificial rail corrugation having 30 mm and 100 mm of wavelengths and 3 mm depth were measured with average wavelengths of 29.97 mm and 90.15 mm and average depth of 2.55 mm. respectively. As such the results, the error of measurements are 0.1 ~ 9.8% for the wavelength and 15% for the depth. Through data acquisition of the on-site test, rail corrugations was detected with wavelengths of 20~21 mm, 36~37 mm and 69~70 mm which is suitable with the results observed by optical camera in panorama images.