Development Of Portable Bolt Crack Detection Device On Brake Disc For High Speed Train

With the development of high speed trains,the safety of train operation is becoming more important.The brake disc is the key part of the train brake system,which determines the performance of the train braking.The brake disc bolt is the fastener connecting the axle and the brake disc,and its reliability is self-evident.However,there is no rapid and effective method to detect the crack of brake disc bolt,which is a potential threat to the safety of train operation The purpose of this paper is to develop a portable bolt crack detection device on brake disc for high speed trains,to realize the qualitative and quantitative and high efficiency detection of the bolt crack.Based on ultrasonic nondestructive testing technology,A-scan pulse reflection method is applied to detect bolt cracks in this paper,and the overall implementation plan of ultrasonic flaw detection system is designed.In the hardware part,the 5M single crystal direct probe is selected as the ultrasonic probe;A sharp pulse ultrasonic transmitting circuit with a pulse width less than 50ns is designed,which can stimulate the transducer to produce high quality ultrasonic signal;The signal conditioning circuit is designed,and the signal is limited,magnified and filtered;the basic circuit design of FPGA and ARM,and the construction of hardware platform.In the software part,the FIFO access of data is realized by the Verilog language on FPGA,the transmission speed matching is completed and the communication with the ARM is realized.C language is used to realize the functions of wavelet threshold denoising,bolt crack detection,bolt size and location determination,human-machine interaction interface,data storage and other functions on the ARM.In order to verify the function and reliability of the equipment,laboratory environment experiments and field experiments are carried out to show that the detection device can achieve more than 1mm of the bolt crack,and it can report the position and the size of the crack automatically.The device has high detection accuracy and low false alarm rate,and the performance of the equipment is stable.Moreover,the simple human-computer interaction and it's intelligent detection greatly improve the detection efficiency which contribute to the safety operation of the train.