The Research Of Piezoelectric Impedance Technology Applying To The Reinforced Concrete Beam

At the moment, more and more research on the piezoelectric impedance technology at home and abroad, and the damage detection has also made certain progress in practical application. However, piezoelectric impedance technology is applied to damage detection is still only in its early stages, only to qualitative analysis of the damage location and the degree of damage is still not very good judgment. Based on the theory of piezoelectric impedance technology, the basic principle of its application in the damage detection was studied. Combining with neural network technology, the damage of reinforced concrete structures was studied in the numerical. A piezoelectric impedance sensor was designed and manufactured.and applied it to the experimental research of reinforced concrete beam damage detection. The research contents and results could be summed up as follows.Firstly, the development of piezoelectric ceramic materials was outlined. the main characteristics of piezoelectric materials and their advantages were introduced. The positive and negative piezoelectric effect of piezoelectric ceramic material and theory of four types of boundary conditions were analysed. The impedance characteristics of piezoelectric ceramic were introduced. The equation of mechanical impedance and the piezoelectric coupling impedance was deduced. The damage detection theory of the piezoelectric impedance was expounded.Secondly, the features and advantages of the technology of artificial neural network were summarized. The artificial neural model and its mathematical expression and BP network design were introduced. The principle of neural network in the application of structural damage identification was analysed. Experimental study analysis flow chart was made. The procedure of neural network to identify for the finite element analysis and experimental was designed.Thirdly, the parameters of PZT input in the finite element method was introduced. The crack depth and crack position change on the influence of the piezoelectric impedance by the finite element analysis software was studied. The two health index method were comparison analysed, and the damage can be identify by them in a certain extent. Combined with the neural network technology data processing method of reinforced concrete beam crack depth and crack position location identification. Successed identify concrete crack of reinforced concrete beam depth and location to a certain extent.Fourthly, piezoelectric impedance sensor can be used for the reinforced concrete beam experimental study have been designed, and its feasibility was verify. The reinforced concrete beam crack damage test scheme is determined. The experimental device was set up. The low frequency, intermediate frequency and high frequency area was discussed one by one. Determined the influence on the piezoelectric impedance in the three frequencies of crack depth change, and crack depth of concrete was judgment through neural network data processing method. Proved that the piezoelectric impedance technology can detect the crack depth of concrete to a certain extent.