埋入混凝土的自感知水泥基传感器受力分析

Force Analysis of Self-sensing Cement-Based Sensors Embedded in Concrete

采用有限元软件ANSYS分析了尺寸、电压电极间距和表面粗糙度对镍粉水泥基传感器与其周围混凝土应力/应变协调性的影响,进而对该传感器的制作参数进行了优化,并对优化传感器埋入混凝土后其自身及周围混凝土的受力状态进行了分析.结果表明:镍粉水泥基传感器的合适尺寸为20mm×20mm×40mm,电压电极间距为5mm,并尽量使其表面粗糙;镍粉水泥基传感器埋入混凝土中的受力状态近似于单轴受力状态,其与周围混凝土的应力差别较大,应变基本协调,将其应用于混凝土结构健康监测时需对测试结果进行修正.

In order to optimize the parameters of the nickel powder-filled cement-based sensors, effect of size, electrode separation and surface roughness of sensors on stress/strain compatibility between sensors and their surrounding concrete was investigated with finite element software ANSYS. The stress states of the optimized nickel powder-filled cement-based sensors and their surrounding concrete was analyzed when the sensors embedded in concrete. The results show that the suitable size and electrode separation of the sensors are 20 min× 20 mm× 40 mm and 5 mm respectively. The surface of sensors should be as rough as possible. The sensors are nearly subjected to a uniaxial stress state when they are embedded in concrete. The stresses of the sensors and their surrounding concrete are quite different, As the strain is compatible, the testing results of sensors need to be modified for ensuring test accuracy when the sensors are used for health monitoring of concrete structures.