阵列解析式超声聚焦换能器研制及空间感测分析方法研究

传统的超声聚焦换能器大都采用单一的压电感测元件作为接收源,接收信号为作用于压电材料上的反射声场积分结果,无法反映反射声场的空间分布特性。采用激励与接收相分离的方式,研制一种新型阵列解析式超声聚焦换能器,利用多个感测元件为接收单元,通过一套基于FPGA技术的高速超声检测系统,实现了对被测试件反射声场的空间分布信号的采集和分析。阐述阵列解析式超声换能器的设计与制作方法,对换能器的多个感测元件的激励响应特性进行标定,利用该换能器的阵列感测元件的空间分布特性,对多角度声场感测信号进行分析和处理。以阶梯试件的台阶高度为测试对象开展空间感测声场测试方法分析试验研究,达到预期效果,为不规则裂缝缺陷检测奠定了基础。

Fabrication of Array-analytic Ultrasonic Focused Transducer and Research of Spatial-sensing Method

The traditional ultrasonic focused transducers are always utilizing single piezoelectric sensor as receiver, and the received signal is the integral of the reflection of acoustic field at the piezoelectric material, but it can’t reflect the characteristics of reflected acoustic field. So that a new approach is presented which excitation and reception are separated to design and fabrication of array-analytic ultrasonic focused transducer. Using a multi-sensing element as receiver by a high-speed ultrasonic testing system based on FPGA technology to collected signals from different angles and analyzed these signals. Firstly, the approach of the design and manufacture of array-analytic ultrasonic focused transducer is expound and the multiple characteristics of excitation and response of the transducer array are calibrated. Secondly, the received multi-angle acoustic field signals are analyzed and processed by using the spatial distribution characteristics of the new type of transducer’s array sensing elements. Finally, the experimental research carries on the object of the different heights of the stairs sample by the approach of spatial-sensing acoustic field measure and the expected result has been achieved. That is build up a good basis for irregular crack defect detection.