应变片粘贴因素对压杆测压的影响

Influence of stickup factor of strain gauge on pressure bar measurement

应变式压杆测压中,需要在杆的适当位置对称粘贴一组应变片,由于杆一般比较细,应变片粘贴的对称性以及附加质量都会对压杆的精确测试带来一定的影响。在直径Φ4 mm压杆的静态和动态标定实验中对该影响进行研究。在实验中观察到弯曲波及对波形平台造成的畸变,给出应变片粘贴位置偏差对测试结果影响的理论估算公式,分析研究不同附加质量情况下的动态波形特征。研究发现,应变片粘贴位置的不对称以及附加质量都会造成压杆测试波形明显畸变,后者还会造成动态灵敏系数的偏大;在尽量去除附加质量时,静态、动态灵敏系数趋于一致。

In the pressure measurement of the strain type pressure bar,a group of strain gauges should be attached symmetrically in the proper position of the bar.Because the bar is usually relatively thin,the symmetry and the additional mass of the strain gauge will have a certain effect on the accurate test of the pressure bar.The effect is studied in the static and dynamic calibration experiments of a 4mm diameter pressure bar.In the experiment,the bending wave and the distortion of the wave platform is observed.The theoretical estimation formula of the influence of the position deviation of the strain gauge on the test results is given,and the characteristics of the dynamic waveform under the condition of different additional mass are analyzed and studied.It is found that the asymmetry of the stickup position of the strain gauge and the additional mass will all cause the obvious distortion of the test waveform,and the latter will cause a greater dynamic sensitivity coefficient.It is also found that the static and dynamic sensitivity coefficients tend to be consistent when the additional mass is removed as much as possible.