振弦式应变传感器温度修正试验

为得到合理的振弦式应变传感器温度修正公式，对自由状态下的传感器、埋置在混凝土收缩徐变试件内的传感器和埋置在钢管混凝土收缩徐变试件内的传感器进行了室外日照温度下的温度修正试验，根据试验结果拟合了不同条件下振弦式应变传感器的温度修正公式，并基于理论公式对其进行了分析。结果表明:自由状态下的传感器应变与温度增加呈正相关，斜率为2.8×10^-6℃^-1；埋入混凝土收缩和徐变试件的传感器应变与温度呈负相关，斜率分别为-2.15×10^-6℃^-1和-2.54×10^-6℃^-1；钢管混凝土表贴传感器应变与温度呈正相关；埋置在管内混凝土收缩和徐变试件的传感器应变与温度增加呈负相关，斜率分别为-2.01×10^-6℃^-1和-1.70×10^-6℃^-1；振弦热膨胀系数和外界测试材料热膨胀系数的差异是造成传感器应变与温度正负相关的主要原因。

Temperature Correction Test of Vibrating Wire Strain Sensor

In order to obtain reasonable temperature correction formula of vibrating wire strain sensor, temperature correction tests about the sensor in free state, the sensor embedded in concrete creep and shrinkage members, concrete filled steel tube (CFST) shrinkage and creep members in the outdoor sunshine temperature were carried out. Based on the experimental results, the temperature correction formulas of vibrating wire strain sensor under different conditions were fitted, and the results were analyzed based on the theoretical formula. The results show that the sensor strain in free state is positively correlated with the increase of temperature, and the slope is 2.8×10^-6℃^-1. The strain of sensor embedded in the concrete shrinkage and creep specimen presents negative correlation with temperature, and the slope is －2.15×10^-6℃^-1and －2.54×10^-6℃^-1respectively. The strains of the sensor embedded on surface of the CFST shrinkage and creep specimens show positive relationship with temperature. The strains of sensor embedded inside of the CFST shrinkage and creep specimens present negatively relationship with temperature, and the slope is －2.01×10^-6℃^-1and －1.70×10^-6℃^-1respectively. The difference between the linear expansion ratio of the steel wire and the expansion coefficient of the external test material is the main reason of the positive and negative correlation of the sensor strain and temperature.