Abstract:
The measurement accuracy of strain electrical measurement method is closely related to the elastic modulus of the measured component. When the elastic modulus of the tested component is as low as hundred megapascals, the “stiffness effect” and “size effect” of the strain gauges are already significant, and the strain field of the component will also exhibit “thickness effect” and “width effect” under the influence of the strain gauges; The above effect significantly increases the measurement error of strain gauges. In order to reduce the error in measuring the hundred megapascals elastic modulus components with strain gauges, this paper establishes a finite element model containing “measured component, adhesive layer and strain gauge”, analyzes the influence mechanism of the above effects, and proposes a correction method based on “one large and one small” strain gauges. The verification experiment shows that by using the dual strain gauge method combined with empirical formulas to reasonably correct the measurement results, the accuracy of strain electrical measurement can be significantly improved.