考虑混凝土弹塑性的植入式GFRP封装FBG传感器应变传递分析

Strain Transfer Analysis of the Embeddable GFRP-Packaged FBG Sensors Considering the Elastoplasticity of the Concrete Host

工程化FBG传感器的封装层引入的应变传递损耗使其具有应变传递误差,需进行应变传递分析。已有研究多聚焦于基体处于线弹性时的应变传递分析,而混凝土结构发生弹塑性变形后的应变传递规律尚未明晰。以植入式GFRP封装FBG传感器为对象,在应变传递分析中引入混凝土的非线弹性本构关系,建立了基体与FBG的应变传递关系,通过有限元模拟验证了该理论推导的有效性。基于理论分析探讨了混凝土弹塑性演化、混凝土标号、传感器半径与标距等因素对应变传递效率的影响,并分析了传感器的尺寸设计。研究表明:平均应变传递率在混凝土弹性阶段变化较小,而到塑性阶段则显著降低,混凝土标号、半径与标距都会对应变传递效率产生较大影响。本研究可广泛用于植入式FBG传感器的应变传递误差修正及设计。

The strain transfer loss introduced by the packaging layer of the industrialized FBG sensor often makes it has strain transfer error,so it is necessary to conduct strain transfer analysis.Most previous studies focus on strain transfer analysis when the host layer is linearly elastic,but the strain transfer law of concrete structures after elastic-plastic deformation is still unclear.The strain transfer anal-ysis on the embedded GFRP-FBG sensor considering the concrete’s nonlinear elastic constitutive relationship is conducted,and the strain transfer relationship between the host material and FBG is derived.The validity of the theoretical derivation is verified by finite el-ement simulation.Based on theoretical analysis,the effects of concrete elastoplastic evolution,concrete mark,the radius of the sensor,and gauge length on strain transfer efficiency are discussed,and the size design of the GFRP-FBG sensor is analyzed.The results show that the average strain transfer rate changes little in the elastic stage of concrete but decreases significantly in the plastic stage.Moreo-ver,the concrete mark,the sensor radius,and the gauge length all have a significant impact on the strain transfer efficiency of the sen-sor.This research can be widely used for strain transfer error modification and the design of embedded FBG sensors.