Abstract:

Experiments of ultrasonic nondestructive testing and its related simulations are developed to investigate the quality of the functional graded material with defects. The acoustic impedance of this materials is changed gradually at the direction of thickness. Water immersion method is used to filter shear wave in experiment, where A scan and C scan are combined to test defects. Amplitude of the echo signal as a function of time can be obtained by A scan, while amplitude of the echo signal of every point in certain depth can be obtained from C scan. The results indicate that the phase position of waveform at the interface is the same as incident wave if the functional graded material without defect. Otherwise, the phase position of that is the opposite in the defect. Transient numerical simulation of the model is performed in this material using the same models and loadings. The result of numerical simulation is to explain the mechanism of the experiment.