Research On Control System Of Temperature And Deformation Self-adjustment Of Smart Concrete Structure

This dissertation was supported by the Key Project of National Science Foundation under grants No. 50238040.Concrete is one of popular engineering structural materials. Some momentous concrete structures must be used for decades even hundreds years. Regular concrete structures for water conservancy usually work in abominable climate and environment, such as concrete dams. Temperature is main load of these structures, and alternant between positive and negative temperature would cause asymmetric deformation, crack, freezing-thawing damage and fatigue damage of structures.In addition, Cement structures such as bridges often come into being distortion or excessive temperature stresses due to the sun radiation, creep, or shrinkage. Therefore, study of diagnostic and control method for momentous structures is important in construction engineering.Based on the analysis of the sensing and acting function of carbon fiber mat concrete , research on the control system were done to adjust temperature differential and deformation of carbon fiber mat concrete laminate beams with experimental and simulating means..The following conclusions and innovation can be obtained:Firstly, the transfer function of the controlled plant was fitted by first order inertial element,the fluctuation of heat transfer coefficient is the main factor of the change of the transfer function;Secondly, dynamic response of the electro-thermal effects of the carbon fiber concrete laminate beams was researched, and it was found that the if we first use the higher power than change the power to keep it when temperature difference arrived at the nearly expecting value.the regulating speed would be greatly improved but with overshoot of different degrees due to the different changing time.Thirdly, fuzzy control method and PID method were used respectively to design temperature self-adjustment controller of carbon fiber concrete laminate beam,by the MATLAB simulation it is found that the PID method has higher speed but is more sensitive to the fluctuation of system parameter ,it is suit to the regulating when the heat transfer coefficient fluctuates diminutively and the structure has little heat transfer with the environment;fuzzy control can be adapt to the parameter variety in a large scale , it is suit to the regulating when the heat transfer coefficient fluctuates greatly.The forth,deformation self-ajustment controller is designed and made based on big-size carbon fiber concrete laminate beam,and deformation self-adjustment experiment is done to explore the prospect of self-adjust concrete in project application.The fruit achieved in this dissertation have important significance to guide the self-adjustment of concrete structures and to impel the development of intelligentconcrete.