School of Information Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
National Institute of Metrology, Beijing 100029, China.
Sensors (Basel). 2023 May 16;23(10):4778. doi: 10.3390/s23104778.
The flexible strain sensor's measuring range is usually over 5000 με, while the conventional variable section cantilever calibration model has a measuring range within 1000 με. In order to satisfy the calibration requirements of flexible strain sensors, a new measurement model was proposed to solve the inaccurate calculation problem of the theoretical strain value when the linear model of a variable section cantilever beam was applied to a large range. The nonlinear relationship between deflection and strain was established. The finite element analysis of a variable section cantilever beam with ANSYS shows that the linear model's relative deviation is as high as 6% at 5000 με, while the relative deviation of the nonlinear model is only 0.2%. The relative expansion uncertainty of the flexible resistance strain sensor is 0.365% (k = 2). Simulation and experimental results show that this method solves the imprecision of the theoretical model effectively and realizes the accurate calibration of a large range of strain sensors. The research results enrich the measurement models and calibration models for flexible strain sensors and contribute to the development of strain metering.
柔性应变传感器的测量范围通常超过 5000 με，而传统的变截面悬臂梁校准模型的测量范围在 1000 με 以内。为了满足柔性应变传感器的校准要求，提出了一种新的测量模型，以解决变截面悬臂梁线性模型应用于大范围内理论应变值计算不准确的问题。建立了挠度与应变之间的非线性关系。利用 ANSYS 对变截面悬臂梁进行有限元分析表明，在 5000 με 时线性模型的相对偏差高达 6%，而非线性模型的相对偏差仅为 0.2%。柔性电阻应变传感器的相对扩展不确定度为 0.365%（k = 2）。仿真和实验结果表明，该方法有效地解决了理论模型的不精确性，实现了大范围内应变传感器的精确校准。研究结果丰富了柔性应变传感器的测量模型和校准模型，为应变计量的发展做出了贡献。
