电阻应变片贴装方位偏差对测量结果的影响

认为电阻应变片可以测量构件受的力、力矩、压力等物理量 ,贴装方位不准确是造成应变测量误差的主要原因 ,分析讨论了电阻应变片在一维、二维应力状态下贴装方位偏差所造成的测量误差及其变化规律 :一维情况下 ,相对误差γ不仅与角偏差△α有关 ,而且还与主应变方向的夹角α和所测件泊松比μ有关 .特别的 ,在α =0 ,△α <5°时 ,γ <1 % (μ =0 .2 85 ) ;α≠ 0时 ,随着α的增大 ,△α对所测γ的影响就越大 .二维 ,电阻应变片贴装方位偏差△α造成测量误差γ与两主应变之比ρ及α角有关 ,当ρ一定时 ,α角越大 ,偏差角△α对测量的影响就越显著 .最后 ,设计了实验 ,对一维应力状态下的分析结果进行了验证 .为实际测量工作及传感器设计、制造提供了参考依据

Effect of the Azimuthal Error of a Strain Gauge on the Measuring Result of Strain

The azimuthal error of a strain gauge is the main cause which leads to the measuring error of strain. The strain error formulas were derived in one dimensional stress state and two dimensional stress state. In one dimensional stress state, α is the angle between the designed direction of strain gauge and the direction of principal strain, △α is the error of α , and γ is the relative error of the measured strain. γ has something to do with not only △α,but also α and μ(Poisson's ratio of the material of measured component). When α=0 and △α<5°,γ<1%(η=0.285); when α≠0 , the effect of △α on γ will decrease with the increase of α. In two dimensional stress state, α is the angle between the designed direction of strain gauge and the direction of principal strain ε 1. ρ is the ratio of ε 1 to ε 2 . △α,γ and μ are the same as above. When α is fixed, the greater α is, the greater the effect of △α on γ is. An example of one dimensional stress state is presented. The results of this paper can provide a basis for the design and manufacturing of sensors.