激光光通量位移计在Hopkinson杆中的应用

Applications of a laser displacement gauge in Hopkinson bar experiments

简要介绍了激光位移测试技术的基本原理及实现方案,准静态和动态标定结果表明该系统可以用于动态测试。给出了激光光通量位移计在Hopkinson杆实验中的3种应用:(1)用激光光通量位移计可以监测试样的横向变形,从而得出试样的动态泊松比;(2)在动态断裂实验中,激光光通量位移计可以监测裂尖张开位移,结合应变片的信息可以得出试样的动态断裂能;(3)将激光光通量位移计和石英晶体应力计相结合可以直接在试样两端得到应力应变信息,用来测量超软材料在中应变率下的力学响应。

A laser displacement gauge（LDG） system is proposed.Both the static and dynamic calibrations are carried out,and the results show that the system is effective for dynamic test.As an efficient measuring method,the LDG can be applied in the Hopkinson bar experiment,such as：（1） the LDG can be used to monitor the radial displacement of the specimen,with which the dynamic Poisson＇s Ratio can be calculated;（2） the LDG can be adopted to measure the crack surface opening displacement of the notch in a dynamic fracture test,and then the dynamic fracture energy can be obtained by associating the signals from the strain gauges mounted on the bars;（3） an innovative Hopkinson bar system for testing ultra-soft materials under intermediate strain rates is developed,where the LDG is employed to monitor the deformation of the sample directly,and two piezoelectric force transducers are sandwiched between the specimen and two bars respectively to measure the weak dynamic loads directly.