Numerical Simulation Of Piezoelectric Smart Aggregate And Its Stress Monitoring Of Concrete Filled Steel Tubular Column

With the development of construction technology, all kinds of super high-rise buildings and wide span bridges with concrete filled steel tubular structure are emerging. Structural engineering accidents occur again and again under the action of earthquake,wind loading and impact, due to the lack of monitoring data,the root cause of structure damage is not totally clear yet,so recently, complex building structure stress and strain monitoring has become hot research issue in the field of civil engineering.The dynamic stress monitoring of the structure mainly adopts resistance-type strain gage,but this kind of sensor can only be decorated on the structure surface,it may not able to monitor the change of stress inside concrete structure,especially concrete filled steel tubular structure. This paper was supported by National Natural Science Foundation of China 《Research of concrete filled steel tube structure time-varying stress monitoring method and earthquake disaster mechanism based on piezoelectric smart aggregate》,Making a marble base piezoelectric smart aggregate based on the positive piezoelectric effect, and apply it to the concrete structure stress monitoring under dynamic loads,main works include the numerical simulation of mechano-electric effect of smart aggregate and the numerical simulation of concrete column and concrete filled steel tubular column time-varying stress monitoring based on piezoelectric smart aggregate. The specific content of the work includes the following aspects:(1)The research of mechano-electric effect of piezoelectric smart aggregate.In order to understand the working mechanism and performance of smart aggregate under unidirectional dynamical loading,we conducted a theoretical analysis, Establishing the mathematical expression of the voltage of piezoelectric smart aggregate and by piezoelectric equation.(2) The parameter analysis of sensitivity coefficient of piezoelectric smart aggregate. using finite element software ABAQUS to do numerical simulation for the mechano-electric effect of piezoelectric smart aggregate and analyzes its parameters,discussing effects of epoxy resin layer thickness and piezoelectric ceramic chip size to sensitivity coefficient of piezoelectric smart aggregate Establishing.(3)The numerical simulation of concrete column time-varying stress monitoring based on piezoelectric smart aggregate,For researching the feasibility of back stepping structure inner stress according to sensitivity coefficient, embedding piezoelectric smart aggregate in the concrete short column,,using finite element software ABAQUS to do numerical simulation,choose C3D8E unit to simulate piezoelectric ceramic chip and C3D8R to simulate concrete column,Applying vertical load on the concrete short column through application of the displacement load system.According to the voltage values of piezoelectric ceramic chip obtained by finite element simulation and its sensitivity coefficient,then deduce the inner stress of concrete column.(4) The numerical simulation of concrete filled steel tubular column time-varying stress monitoring based on piezoelectric smart aggregate.on the foundation of the simulation of concrete column time-varying stress monitoring, The results showed that:the simulation results indicate the model is reasonable and piezoelectric transducer can be well used to monitor internal dynamic stress of concrete structure.