Numerical simulation and measurement of acoustic pressure of  focused ultrasonic vibration spherical shell
                                             WANG Zhongwang1,2, LI Hua1,2, WANG Bangfu1,2, XIE Ou1,2, REN Kun1,2
（1.College of Mechanical Engineering, Suzhou University of Science and Technology, Suzhou 215000, China； 2.Suzhou Key Laboratory of Precision and Efficient Machining Technology, Suzhou 215000, China)


Abstract: In order to solve the problems of complex measurement of sound pressure field and energy loss in high intensity focused ultrasound, a new type of focused ultrasonic vibration spherical shell was designed. The distribution of sound pressure field in focused ultrasound vibration spherical shell by precise and convenient measurement method was studied. The model for calculating the sound pressure field of focused ultrasonic vibration spherical shell with opening diameter of 60 mm was established. The sound pressure perpendicular to the axis in the focal plane of focused ultrasound was calculated theoretically. The influence of the different aperture of focused ultrasound spherical shell on the distribution of the sound pressure at the axis of sound pressure was analyzed. At the same time, the sound pressure level of focused ultrasonic spherical shell was simulated by COMSOL. Secondly, probe hydrophone measurement system was built to verify the distribution of sound pressure field of focused ultrasonic vibration spherical shell. The results show that the acoustic pressure of the main flap near the focal point increases with the increase of the opening radius of the focused ultrasonic vibrating spherical shell. When the opening radius increases, the focal spot become smaller, the sound pressure increases at the focal point, and the acoustic energy is more concentrated. The focused ultrasonic vibration spherical shell system has remarkable focusing characteristics. The acoustic focal length of focused ultrasound vibration spherical shell is more in line with the geometric focal length and the error is smaller than that of high intensity focused ultrasound. Numerical simulation is basically consistent with experimental measurement.
Key words: ultrasound focusing; focused sound field; sound pressure measurement; probe hydrophone