小试件材料弹性常数超声测量系统的研制

本文针对小试件块体纳米材料力学性能测试的特殊需求，设计开发了一套小试件材料弹性常数超声精密测量系统。系统由线聚焦PVDF探头、四轴精密运动平台、NI PXI总线嵌入式控制器、超声脉冲产生／接收仪以及数字记忆示波器组成。系统基于声学显微镜技术，利用同时测定纵波和漏表面波波速来表征材料的弹性常数等，既适用于各向同性材料，又适用于各向异性材料。试验结果表明本测量系统工作良好，能够满足试验要求，为进一步评价小试件纳米材料制备工艺和表征纳米材料的力学性能奠定了基础。

Development of an ultrasonic system to measure material elastic constants of small sample

An ultrasonic system to measure material elastic constants of small sample was developed.It aims at the especial needs in testing mechanical properties of bulk nano-material.The system includes a line-focus PVDF transducer,a four-axis precise moving framework,an NI PXI bus embedded controller,an ultrasonic pulse generator/receiver and a digital oscilloscope.Based on acoustic microscope technology,material elastic constants are determined by measuring longitudinal wave and leak surface wave velocity simultaneously.This method is suitable not only to measure the elastic constants of isotropic material,but also those of anisotropic one.Experimental results show that the system functions nicely.