레일 매립형 자기센서를 이용한 차륜 답면의 실시간 결함 검출 및 평가

Abstract

As the icon of green technology, the express train with carbon neutrality consumes less energy than other transportation modes. On the other hand, its wheel treads are damaged by high kinetic energy and friction due to heavy weight and high speed. The damages can propagate to fracture the wheels. Therefore, crack damages need to be inspected and maintained under control. However, the time for crack damage inspection needs to be reduced to meet the time limitation in the maintenance factory. The purpose of this paper is to develop a real time non-destructive testing method of express train wheels, which are tested when the express train enters the maintenance factory or garage. In the proposed method, the crack inspection system is buried in the rail. Therefore, every wheel can be tested when the train passes along the rail installed with the inspection system. The proposed method was verified by following experiments. Three methods of inspection are carried out with the testing equipment installed on the wheels, installed at the bottom of the train, buried in the rail, respectively. Also the merits and demerits of these methods are compared and discussed. A part of wheel tread was magnetized in the rotation direction, and the distorted magnetic field due to a crack was measured by using the linearly integrated Hall sensors array. The results indicated the validity of the firstand the second method-testing with installation on the wheels and installation at the bottom of the train. A part of wheel tread was magnetized in the vertical direction, and the distorted magnetic field due to a crack was measured by using the linearly integrated differential type Hall sensors array. The results validated the third method the rail-buried-type. The results validated the third method according to the abovementioned experiments results, permanent-type magnets and 2-dimensional differential-type Hall sensors array were buried in the rail. By this method, the wheels can be inspected as they pass the inspection zone. Laboratory simulation and on-the-spot inspection verified the practicality of the proposed method. A real-time nondestructive testing system for wheel treads was developed. The developed method offers reduced testing time with high accuracy of crack inspection in the wheel tread.