It is of great significance to monitor and quantify the defects in the thin segmental spherical shell components. In the paper the guided wave’s inspiring method has been obtained from the wave-mode conversion based on the theory of the guided wave propagating in the thin spherical shell. Using the wavelet to process the testing signal, and the ellipse localization imaging algorithm, the defect’s localization and orientation can be detected accurately. Experimental results show the defect’s direction and location can be detected effectively and clearly.

When detecting torque with surface acoustic wave (SAW) resonator sensors, the real strain of the host structure is not exactly consistent with the strain of SAW resonator due to material mismatch and the finite-thickness adhesive problem. A 3-layer (host structure, adhesive, and resonator layer) model is established. Finite-element Analysis (FEA) was used to investigate the strain transfer from the metal substrate to the SAW resonator (SAWR) through a bonding layer. The results show that the values of the strain transfer rate of FEA agree well with the experimental data. It can be concluded that FEA is of great value for SAW sensor design and sensing applications.

The focus law and acoustic field computation method about circular arc linear phased array have been discussed in the paper. Acoustic field of transducers is given by the use of the coordinate transformation and an approximation with rectangle element instead of circular arc element, and was calculated using Rayleigh-Sommerfeld Integral.

The edge of material loss is crucial for material loss evaluation. Lamb wave tomography and model-based edge detecting have been used in isotropic media. Time of flight and velocity of lamb wave are ultrasonic signal features to reconstruct the edge map of material loss. The correlation technique is employed to get the time of arrival more accurate. An ellipse model is used to represent the defects with apparent directional property, and edge detecting will be realized by it. The reconstructed map shows clearly that edge detecting method in this paper is efficient for material loss detection.

The components of the ultrasonic phased array transmitting system is analyzed and theoretical model of ultrasonic phased array transmitting system is developed. The simulation result shows that the model is reasonable.