Numerical Analysis of Ultrasonic Scattering in Solid and Study of Dynamic Photoelastic
|School||Huazhong University of Science and Technology|
|Course||Mechanical and Electronic Engineering|
|Keywords||Ultrasonic Scattering Numerical analysis Dynamic photoelastic|
Ultrasonic nondestructive testing is an important method to identify these defects. Butthe echo signal contains only part of the information of pulse ultrasonic scattering from thedefects. So it is necessary to learn how the defects and pulse ultrasonic interact with eachother. That is the reason why the study about the numerical analysis between defects in solidand major part in dynamic photoelastic is conducted in this paper.The simulation acoustic velocity is calculate and compared it with theoretical acousticvelocity to verify the validity of the method presented in the paper. The influences of meshdestiny, time step size, type meshing and element shape to the simulation results are analyzedand present how to model defects. These analyses will give specific numerical examples someguidelines.Circular hole and fissure are typical defects, so the numerical analyses of scattering ofplane longitudinal wave from these the two type defects were conducted. The snapshot ofwave field in different time are given and analyzed to study the scattering of ultrasonic fromthese defects.The ultrasonic and strobe light synchronous control system is the main and importantpart in the dynamic photoelastic method. Pulse generator is used to drive transducer togenerate ultrasonic. The rising edge of its synchronization pulse is applied to achieved highprecision delay by Verilog based FPGA. Then a narrow pulse is exported and amplified todrive the strobe light. So the ultrasonic and strobe light synchronous control system isdesigned and made.