Zhao Yazhi, Zhang Fengling, Ai Yanting, Tian Jing, Wang Zhi
Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aviation Propulsion System, School of Aero-Engine, Shenyang Aerospace University, Shenyang 110136, China.
Sensors (Basel). 2025 Mar 6;25(5):1633. doi: 10.3390/s25051633.
High-temperature strain gauges are widely used in the strain monitoring of the hot-end components of aero-engines. In the application of strain gauges, the calibration of the gauge factor (GF) is the most critical link. Evaluating the uncertainty of GF is of great significance to the accuracy analysis of measurement results. Firstly, the calibration test of the GF of the Pt-W high-temperature strain gauge was carried out in the range of 25 °C to 900 °C. The real test data required for the uncertainty evaluation were obtained. Secondly, the guide to the expression of uncertainty in measurement (GUM) and the Monte Carlo method (MCM) were used to evaluate the uncertainty of GF calibration test. The evaluation results of GUM and MCM were compared. Finally, the concept of the weight coefficient W was proposed to quantitatively analyze the influence of each input on the uncertainty of the output GF. The main uncertainty source was found, which had important engineering practical significance. The results show that the mean value of GF decreases with the increase in temperature nonlinearly. At 25 °C, GF is 3.29, and at 900 °C, GF decreases to 1.6. Through comparison and verification, the uncertainty interval given by MCM is closer to the real situation. MCM is superior to GUM, which only uses prior information for uncertainty assessment. MCM is more suitable for evaluating GF uncertainty. Among multiple uncertain sources, the weight coefficient W can effectively analyze Δε as the main uncertain source.
高温应变片广泛应用于航空发动机热端部件的应变监测。在应变片的应用中，应变片灵敏系数（GF）的校准是最关键的环节。评估GF的不确定度对测量结果的准确性分析具有重要意义。首先，在25℃至900℃范围内对Pt-W高温应变片的GF进行校准测试，获取了不确定度评估所需的实际测试数据。其次，采用测量不确定度表示指南（GUM）和蒙特卡罗方法（MCM）对GF校准测试的不确定度进行评估，并对比了GUM和MCM的评估结果。最后，提出权重系数W的概念，定量分析各输入量对输出GF不确定度的影响，找出了主要不确定度来源，具有重要的工程实际意义。结果表明，GF的平均值随温度升高呈非线性下降，25℃时GF为3.29，900℃时GF降至1.6。经对比验证，MCM给出的不确定度区间更接近实际情况，MCM优于仅利用先验信息进行不确定度评定的GUM，MCM更适合评估GF不确定度。在多个不确定来源中，权重系数W能有效分析出作为主要不确定来源的Δε。
