Ultrasonic Inspection Of Surface And Internal Defects Of High Speed Rail Wheels Methods And Experimental Research

As an important part of high-speed rail,wheels have a very important impact on the safe operation of trains.With the continuous improvement of the speed of high-speed rail,its safety has been paid more attention to by people.In view of the special requirements for wheel safety of the current high-speed railway with a speed of 350km/h.This paper summarizes the predecessors’ detection of highspeed rail wheel defects,and applies ultrasonic inspection technology to the detection of wheel defects.Also studies the methods of detecting defects on the surface and internal of the high-speed rail wheel rim.(1)Firstly we Use the finite element simulation software COMSOL to numerically simulate the detection process of laser ultrasound and phased array ultrasound.In the simulation study of laser ultrasonic testing,the propagation process of laser-excited surface waves under surface V-shaped cracks of different lengths and angles is simulated.Time-frequency analysis of the ultrasonic signal shows that as the length of the crack increases,the amplitude of the reflected surface wave is increasing,while the change in the angle of the crack has little effect on the reflected surface wave.Finally,a calculation formula for quantitatively characterizing the length of surface cracks was obtained,and the correctness of the formula was verified.(2)In the numerical simulation of phased array ultrasound,through the finite element simulation of the internal defects of the rim with different depths,different shapes,different widths and lengths,the ultrasonic signals under different working conditions are obtained.We analyzed the obtained signals in the time domain and frequency domain respectively,and realized the qualitative characterization of internal defects by the ultrasonic wave excited by the piezoelectric wafer.(3)At the end of this paper,an advanced ultrasonic phased array automatic inspection platform is used to detect defects of different sizes and positions on the test block.The analysis of the experimental data verifies that the experimental platform is suitable for the detection of internal defects.The wheel with unknown internal defects was detected,and the B-scan image of the defect was obtained,and the precise detection of the size and position of the internal defect of the wheel rim was realized.Through the above research work,the results obtained can provide a theoretical reference for the detection of defects on the surface and internal of high-speed rail wheels.