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.

Visual stimulator is one of the key factors that affect the steady-state visual evoked potential (SSVEP). Research and development of brain-computer interface (BCI) system based on SSVEP have priority to consider the design and implementation of visual stimulation. Compare with visual stimulators for particular applications, this paper presents a visual stimulator that is portable and easy to modify apparatus, which is suitable for expanding the application of SSVEP based BCI system. This article induces a visual stimulator based on ARM microcontroller for BCI. The stimulator uses a common USB interface, achieving multiple selective stimulus methods. The system features include visual stimulation, parameter setting and display, the experimental results feedback display. Experimental data prove that this stimulator can be used for almost all types of brain-computer interface based on visual stimulation experiments, and have a portable operating mode, flexible parameter settings , and easy operation.

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 curved structural plate components have been widely used in petroleum, natural gas, chemical industry, and other industries fields, monitoring and detecting the curved structural plate components flaw has a great significance for improving the components integrity, reliability and lifespan in service. Based on the elastic wave fundamental theory, elastic wave equations, and phase velocity dispersion characteristic curves in curved plate component, the article gives the phase velocity practical detecting method. By using thecomsolfinite element software, the author proposed a wave propagating forward modeling analytical method, which gives a guidance to study the relationship between the wave and the flaw. By adopting the ellipse algorithm, the article proposed a positioning and imaging method which was used to locate the flaws position and distinguish the flaws direction. Based on the theoretical and technical analysis above, a number of experiments has been done, and the results shows that the detecting and imaging method can locate and image the flaws position and its geometrical morphology precisely for the curved plates flaw detecting.