The Development Of The Array MFL Testing Equipment And Quantitative Analysis Of Rail Cracks

The rapid development of high-speed railway has promoted the development of national economy.However, the health state of rail is directly related to the traffic safety, and the security of high-speedrailway has been a major and advanced issue at present. MFL technique is commonly used in railwaydefect detection, and the the quantitative of defects has always been an important topic in this field. Inthis paper, we establish a high-speed MFL testing platform, which uses multi-channel sensors array todetect cracks in real time at high-speed, and quantitative the cracks based on the MFL signals. With theexperiment and quantitative results, the paper illustrates that the mulyi-channel MFL detecting methodis useful and feasible in the nondestructive inspection and the crack quantity.Compared with the conventional MFL testing method which uses single-channel sensor, themulti-channel testing method can obtain more comprehensive information of crack, which is moreconducive for the quantitative of defect. In this paper, we establish a multi-channel MFL testingequipment which includes the design of the device and the experiment, and analys the relationshapebetween the different kinds of cracks and the MFL signals, and the ones between the lift-off and MFLsignals. The equipment design is about the headware design and software design of the modules. Thenwe detect the railways and quantitative the cracks based on the neural networks with the MFL signalsin single-channel detection method and multi-channel ones respectively. In the quantitative of the angelbetween defect plane and the railway surface, in addition to tradition way of the characteristic valuesextracting, the paper proposes a method to utilize the asymmetry of the MFL signals, and thequantitative results demonstrate the feasibility of the method. In the quantitative of the angel betweendefect plane and the deriving direction, we utilize the MFL distribution of multi-channel signals toimprove the quantitative accuracy. Besides, the simulation results indicates that the detecting lift-offwill inluences the testing results.