相控阵超声阵列换能器中阵元参数对声场的影响研究

Research on the Influence of Array Element Parameters on the Sound Field in Phased Array Ultrasonic Array Transducer

为探究相控阵超声阵列换能器中不同阵元参数对声场的影响,以相控阵超声波检测基本原理和声场辐射理论为支撑,应用MATLAB软件进行数值模拟分析,建立辐射声场模型,进行不同参数下的阵列换能器指向性和声场分析。分析了阵元各项参数变化时对波束质量、聚焦范围、成像效果的影响,结果表明:阵元中心频率过小会使成像分辨率过低,阵元中心频率过大会使声场穿透力弱,检测深度浅;阵元数的增加显著提高成像效果,但是也会使成本大大提高;当阵元宽度由0.1λ增加到0.3λ,成像效果显著改善,再增加到0.6λ,成像效果改善不明显;阵元中心距增加会提高聚焦精度和成像效果,但是超过0.8λ时,成像效果急剧下降;偏转角度小于30°时,成像效果稳定且清晰,当偏转角度过大时,成像效果明显变差;聚焦深度太小使得声束聚焦性差,成像效果不好,当聚焦深度大于检测表面,成像效果好。对于指导实际超声相控检测具有一定指导意义。

In order to explore the influence of different array element parameters on the acoustic field of phased array ultrasonic array transducer,based on the basic principle of phased array ultrasonic detection and acoustic field radiation theory,the numerical simulation analysis is carried out by using MATLAB software,and the radiation acoustic field model is established,and the directivity and acoustic field of array transducer under different parameters are analyzed. The comparative analysis method is used to analyze the influence of various parameters of the array element on the beam quality,focusing range and imaging effect. The conclusion is that the imaging resolution will be too low if the array center frequency is too small,and the acoustic field penetration is weak and the detection depth is shallow. The increase of the number of array elements can significantly improve the imaging effect,but it also greatly increase the cost. The width of the array element will increase when the center distance of the array element increases from 0.1λ to 0.3λ,the imaging effect is significantly improved,and then to 0.6λ,the improvement is not obvious. The increase of the array center distance will improve the focusing accuracy and imaging effect,but when it is more than 0.8λ,the imaging effect drops sharply. When the deflection angle is less than 30°,the imaging effect is stable and clear. When the deflection angle is too large,the imaging effect will be significantly worse. If the focusing depth is too small,the acoustic beam focusing property is poor,and the imaging effect is not good,and the focusing depth is greater than the detection surface,the imaging effect is good.This conclusion has certain practical significance for guiding the actual ultrasonic phased detection.