A controllable circular ring acoustic focused field

Abstract

Based on Huygens principle about the aspect of phased array, this paper presents a structure of cylindrical acoustic transducer consisting of circular ring piezoelectric transducer elements in radial vibration mode, which can be used to achieve the ultrasonic nondestructive test for the cylindrical scanning acoustic field in three-dimensional space. By analyzing the acoustic field of a single ring line source and a single element, the sound field distribution of the phased array is obtained for constructing circular ring acoustic focused field. By means of the phased array incentive mode, the phase difference of driving signals is generated and forms a regular time delay; with the accomplishment of sound field scanning in cylindrical three-dimensional space, the circular ring acoustic focused field can be controlled in real time.Theoretical analysis and finite element simulation results demonstrate that the size of the circular ring acoustic focused field can be controlled by the numbers of the excited array elements, which are 4, 8, 16 and 32 respectively in our work. We find that with more array element numbers, the circular ring acoustic field has better focused features. The radius size of the circular ring acoustic focused field can be controlled by the different locations of the focus positions which are 30 and 50 mm respectively in our work. And we find that as the distance between the focus positions and the center of piezoelectric wafer becomes longer, the radius of the circular ring acoustic focused field becomes bigger, and the position of the focus is equivalent to the radius of the circular ring acoustic focused field. The movement along the axial direction of circular ring acoustic focused field can be controlled by the angle of deflection, which are set as 0, 10 respectively in our work. And we find that the circular ring acoustic focused field is deflected in a corresponding deflection angle along the Z-axis, and the moving distance is FZ = F/sin . With the theoretical analysis and the experimental simulation, it can be shown that the structure of cylindrical acoustic transducer array presented in this paper could create an adjustable circular ring acoustic focused field and can potentially provide an acoustic field scan method in detection ultrasound, medical ultrasound and other areas of a cylindrical space.