Ultrasonic Array Imaging Of Train Rim Crack Based On Vector Total Focus Method

Defect detection of wheel rims has always been the focus of non-destructive testing of railways.It has great significance for ensuring the safety of railway operation.Based on the ultrasonic synthetic aperture focusing technique,the contact and water immersion imaging algorithms are studied.Combined with the vector total focus algorithm,the angle detection of microcracks is realized.In addition,the total focus imaging algorithm based on arc interface is obtained by combining the geometric model of acoustic wave propagation at the arc interface.Finally,the interface adaptive fitting algorithm is introduced to realize the coordinate fitting and internal defect imaging of the arbitrary curve interface.Good results were obtained.1?The synthetic aperture algorithm is studied,and the contact method total focus imaging algorithm is realized.Combined with the ray tracing method and the Fermat principle,the full focus imaging algorithm of the water immersion method is realized.In addition,according to the law of the reflection of sound energy on the defect,the research of vector total focusing algorithm is carried out.Combined with the difference of the law of sound wave energy propagation by contact and immersion detection method,the vector total focus algorithm based on both methods is obtained.The result is less error and the angle information of the microcracks can be displayed.2?The geometric model of the acoustic wave propagation at the arc interface is analyzed.The coordinate position of the refraction point on the arc interface is calculated by the Fermat principle and certain boundary conditions.Then,according to the principle of the ray tracing method,full-focus imaging of the inside of the circular arc interface object is realized.The accuracy of the algorithm is verified by resolution analysis and verified by simulation.Finally,the effectiveness of the flaw detection on the internal defects of the rim is proved by experiments.3?An adaptive curve fitting algorithm was introduced for curve fitting the surface of an unknown object.Get the surface position information of the object.An adaptive surface object imaging algorithm is obtained by combining the acoustic wave propagation geometry model,and the internal imaging of the object achieves good precision.