背衬对压电传感器瞬态特性影响的模拟研究

Simulation Study of the Effect of Backing on the Transient Properties of Piezoelectric Transducer

接收信号在换能器压电层中的多次反射及波形转换对超声检测的灵敏度和分辨率有重要影响,提高其接收性能的关键是优化换能器背衬结构与材料参数。该文采用Ansys软件中力-电耦合瞬态模拟法,分析了背衬结构的几何参数、材料参数对压电直探头瞬态接收性能的影响,得到了压电换能器中不同时刻的弹性波场、电场分布及输出电压响应曲线,拟合了换能器灵敏度、分辨率与背衬结构几何、材料参数间的关系。研究结果表明,合理选择背衬结构与材料参数对消减接收信号的多次反射,提高换能器接收性能有明显的作用。运用有限元软件分析背衬结构对压电探头瞬态接收特性的影响,是优化背衬结构与材料参数重要方法之一。

The unwanted multi-reflection of the receiving signal in the piezoelectric ceramic layer of the sensor will reduce the sensitivity and resoluiton of the ultrasonic inspection system.Optimizing the backing structure and material parameters are the key to improve the receiving performance of sensor.Contrast with the traditional theory and experimental methods,the effectd of the sizes and material parameters of sensor backing structure on the transient properties of piezoelectric sensor have been optimized by Ansys software.From the modeled transient response,the elastic wave field,the electric field distribution and the output voltage response curve at different time have been given.The relationship curves about the size and material parameters of the sensor backing structure versus the sensitivity and resolution have been fitted.It has been found that the proper structure and material parameters can decreases the multi-reflection of the receiving signals and improve the receiving performance of sensor significantly.The FEM is one of the useful methods to optimize the backing structure size and the material parameters of the sensor.