Abstract: In order to explore the influence mechanism of receiving aperture on imaging and testing of synthetic aperture array for ultrasonic guided waves, the receiving matrix (RM) is proposed to discuss imaging theory of synthetic aperture array for ultrasonic guided waves. Taking the line synthetic aperture array of ultrasound SH (Shear horizontal) guided waves in plate as an object, the receiving aperture is discussed by using the receiving amplitude matrix (RAM) and the receiving flight-time matrix (RFTM), the conic characteristic of line array signals and the synthetic aperture imaging algorithm are analyzed, from which the influence mechanism of the full-rank receiving aperture (FRRA), the half-rank receiving aperture (HRRA) and the unit-rank receiving aperture (URRA) on imaging and testing of synthetic aperture array are emphasized especially. The research result shows that the RAM and the RFTM have the same rank, which rank is not only proportional to the number of receiving array elements, but also determines the image Signal-to-Noise ratio (SNR), and image SNR may be monotonically increasing with increasing of RM rank. However, the image SNR of HRRA is close to that of FRRA, the image SNR of URRA is the smallest and which image background noise is the strongest. The imaging experiment verify the validity of the theory analyzing proposed and indicate that the rank of RM is a key influencing factor on imaging and testing of synthetic aperture array, and the RM is a powerful tool for analyzing the influence mechanism of receiving aperture on imaging and testing, which would provides important foundation for further research and application of imaging and testing of irregular array for ultrasonic guided wave.

Key words: imaging and testing, receiving matrix, synthetic aperture array, ultrasonic guided waves