High-speed Rail Crack Magnetic Flux Leakage Testing Technology Research

With the advent of the era of high-speed rail, traffic railway have some new features: high-speed, heavy-duty and high-density. Rail defects caused by rolling contact fatigue become main rail defect, which causing the train to run a huge security risk. The railway departments need detection apparatus and method for accurate and efficient detection of cracks and other defects of high speed railway. Through the analysis of the electromagnetic properties of ferromagnetic material, magnetic flux leakage non-destructive detection technology is a suitable non-contact rail defect detection technology.This article embarks from the theory, studies the principles of DC magnetic flux leakage testing and AC magnetic flux leakage testing technology and the difference between each. According to the principle of magnetic leakage has developed a set of rail crack detection system, including the hardware design and software design. Through change of the incentive device, the system can be respectively used for DC magnetic flux leakage testing and AC magnetic flux leakage testing. Using the two kinds of magnetic flux leakage testing modes respectively on the artificial surface crack, artificial sub-surface crack, artificial buried blind hole, high speed turntable artificial surface crack and crack of rail natural specimen to study. Detection and analysis of signals of various defects, and for the signal of array detection experiments were 3D imaging display, which convenient visual defect analysis. And puts forward the calculation method for defect resolution of systems,through using the resolution of systems accurately comparative study on signal of all kinds of rail defect using two detection technology, which under hand push, motor low-speed and motor high speed three kind of inspection condition. Finally, through the vehicle experiment, to verify the feasibility of detection method and detection system of the rail crack detection. Through the experimental study, we can analyze the more suitable detection circumstances of DC magnetic flux leakage testing and AC magnetic flux leakage testing and using the complementary advantages of the two kinds of detection technology, which provides a basis for optimal detection scheme of rail defects, but also provides a theoretical basis for the design of rail defect detection equipment with multiple functions.