The Detection Method Of Vehicle Bolster Damage Based On Ultrasound Tomography Technique

In recent years,with the rapid increase of running speed and bearing capacity of subway vehicles,various components of subway vehicles have been subjected to more complicated loads.The bolster is an important part of the connection between the undercarriage and the bogie.It bears various alternating loads and the operating conditions are complex.It is easy to cause damage and affect the safety of the train.Therefore,it is of great theoretical significance and practical value to study the damage of the bloster and find the law of damage and the method of exploring the effective damage detection to improve the safety of train operation.Aiming at the damage of the bolster of the subway car body,this paper studies the testing principle of the body bolster damage based on the elastic wave and put forword the corresponding test method and designs the testing device for the damage of the body bloster.The main research contents are as follows:(1)A mechanical analysis is performed on the elastic body of the body bloster and the wave velocity formula of the longitudinal wave is derived.The relationship between the wave velocity and the elastic modulus is established.Then the material damage is established according to the elastic modulus method in the damage mechanics.The relationship between the elastic modulus and the modulus of elasticity is used to establish the functional relationship between the material damage and the wave velocity.Finally,the damage test principle and test model of the subway body bolster are determined.(2)Through the study of the damage test principle of the bolster and the analysis of test model,the damage of the bolster can be characterized by the distribution of the wave speed inside the bolster.Therefore,it is particularly important to solve the wave velocity distribution inside the bolster.This paper proposes to use ultrasonic tomography method to obtain the internal wave velocity distribution map of the bloster,including the calculation principle of ultrasonic tomography and the choice of algebraic reconstruction algorithm.(3)In view of the damage detection of the body bolster,the hardware system is selected,and according to the principle of ultrasonic tomography and algebraic reconstruction algorithm,using MATLAB GUI design platform for the development of ultrasonic tomographic imaging software systems.Finally,through the ultrasonic tomography damage detection test of the damaged aluminum alloy plate,the function of the ultrasonic tomography software system of the bolster is tested and verified.(4)Taking a subway body bolster as the test object,the design of the test scheme for the damage detection of the body bolster is first performed,and then the damage test and the time data of the body bolster are carried out according to the test scheme.Finally,the experimental data are analyzed and the results of the damage caused by ultrasonic tomography detection method are compared with the actual damage situation.