The Research Of Interfacial Damage Detection Of CFRP-concrete Bonding Interface Based On The Piezoelectric Ceramic

Carbon Fiber Reinforced Polymers(CFRP)are widely used in the maintenance of structures in recent years due to their advantage of high intensity,light quality and excellent durability.However,the interface bonding between CFRP and reinforced structure is relatively weak,and prone to occur interfacial debonding,which directly affects the safety and durability of the reinforced structures.Therefore,it is of great significance for CFRP strengthening structure engineering to develop a practical,economical,effective and convenient method of detecting the interfacial debonding damage.Here in this master thesis,the degree candidate investigate the interfacial damage between CFRP and concrete interface using piezoceramics technology.In this paper,we set up different types and sizes of concrete specimens wrapped by CFRP to interfacial simulate damage which researched by piezoceramics technology.The degree candidate apply Wave-based and Electro-mechanical impedence method,and put the emphasis on extraction of damage characteristic parameters of excitation signal and damage identification method to investigate the interfacial damage identification.The main research work is as follows:Firstly,according to the needs of actual engineering structures and monitoring method,and made a further introduction on the manufacturing and packaging process of embedded piezoelectric actuator.Secondly,we investigated the CFRP-concrete interfacial simulate damage by wave-based method,and applied sine signal and the frequency sweep signal as excitation signal.The results show: the amplitude of the sine signal and the wavelet packet energy value of the frequency sweep signal all show good sensitivity to two kinds of interfacial damage;The damage index DI of sine signal amplitude is positively correlated with the extent of the damage,while the wavelet packet energy value EI of the frequency sweep signal is negatively correlated with the degree of the damage.The experimental results show that the method based on piezoelectric ceramics wave-based method can effectively identify the debonding damage of CFRP-concrete interface,and the damage index DI and the health index EI can both reflect the extent of the debonding damage.Thirdly,we investigated the CFRP-concrete interfacial simulate damage using Electro-mechanical impedence method.The results show: The impedance curve can be used to preliminarily identify the debonding damage;the root mean square damage index RMSD can be used to evaluate the debonding damage effectively.It is obvious that the Electro-mechanical impedence method is effective for the identification of interfacial debonding damage.Fourthly,we investigated the real-time monitoring of interfacial debonding process of CFRP plate reinforced RC beam using Electro-mechanical impedence and Wave-based method.The results showed that the damage index DI,the health index EI,and the root mean square damage index RMSD were effective to explain the process of CFRP-concrete interface debonding progress.Therefore,the Electro-mechanical impedence and Wave-based method are suitable for the detection of damage of CFRP-concrete interface.