Excitation Characteristics Of Multiloop Energy Exchange Arrays For Guided Wave Applications In Pipelines

Pipeline safety is an important component of national security,and establishing a full lifecycle management system for pipelines is one of the important guarantees for the long-term stability of the country,ultrasonic guided wave is one of the methods for non-destructive testing of pipelines.The traditional single ring ultrasonic guided wave detection system excites ultrasonic guided wave with limited energy,multiple modes,and it is difficult to ensure that the coupling effect between the transducer and the pipeline is completely symmetrical.The above problems will lead to limited detection distance,difficulty in mode separation,and complex echo signals,affecting the accuracy and accuracy of pipeline defect detection.Therefore,the ultrasonic guided wave excitation device with multi ring transducer array is adopted in this paper to increase the energy of the ultrasonic guided wave,achieve the formation of the ultrasonic guided wave in the pipeline that is approximately single mode and single direction,and consider the impact of the asymmetric distribution of the transducer on the defect detection results,so as to improve the accuracy and accuracy of defect detection.The content includes theoretical research,numerical analysis,and non axisymmetric research on the excitation characteristics of multi ring energy transfer arrays.(1)Theoretical research on the excitation characteristics of multi ring energy exchange arrays.First,according to the geometric parameters and material parameters of the pipeline,the Navier Equations of motion is solved,and the dispersion curve is obtained.The ideal working mode is determined as the longitudinal mode L(0,2),and the working frequency is 175KHz.On this basis,theoretical derivation is conducted on how to use a multi ring energy transfer array to excite longitudinal modes,and it is concluded that when the transducer is uniformly and symmetrically loaded in a circumferential direction,both L(0,1)and L(0,2)modes will be excited simultaneously.To suppress the L(0,1)mode,the superposition theory of waves was used to analyze the multi ring transducer array.It was found that by adjusting the ring spacing of the multi ring transducer array and the phase difference between the excitation signals,an approximate L(0,2)longitudinal mode guided wave can be formed in the pipeline.(2)Numerical analysis of the excitation characteristics of multi ring energy exchange arrays.Establish a numerical analysis model of a multi ring energy exchange array using ANSYS software,obtain the L(0,2)modal energy values of the double ring,three ring,and four ring,and determine the use of a double ring structure;Further analysis of the influence of ring spacing and phase difference on the guided wave mode and direction in pipelines shows that when the ring spacing is λ/When the integer multiple of 4 and the phase difference is an integer multiple of π/2,L(0,2)mode guided waves can be generated in a single direction of the pipeline.(3)Non axisymmetric study of multi ring energy exchange arrays.The numerical analysis model of a dual ring transducer array was used to simulate non axisymmetric loading.The influence of the circumferential loading angle of the dual ring transducer and the energy of the excitation signal on the echo signal was analyzed.The results showed that when the circumferential loading angle of the transducer was greater than 180 degrees,the identification of ipsilateral defects could be completed.At the same time,cloud images could be used to detect pipeline defects and identify the distribution status of the transducer array.