Experimental Study On The Characteristic Of Acoustic Emission Of Prestressed Concrete Structure

As a new current passive non-destructive testing technology, acoustic emission technique is powerful tool for evaluation the performance of the material and condition of the structure,with real-time, dynamic, convenient, intuitive, continuous, etc, of which the principle is simple,and can well provide the warning to the state of security of the structure and the evaluation to the degree of damage. In this paper, the characterization of acoustic emission was explored and researched in the experiment of prestressed concrete structures by acoustic emission technique. The main contents and findings:(1)Trying to carry out the study of the feature of acoustic emission on simple supported prestressed T-beam, to analyze received acoustic emission parameters, getting the cracking time of the beam and finding the appearance of the crack have some influence to the detection of wave.The linear location technique was used, with a good location to the position of the crack.(2)Acoustic emission was employed to simple supported prestressed box beam study,through the analysis of the AE parameters vs. time distribution, found it can well describe the state of crack propagation in the beam.The correlation between AE parameters analysis was studied and found the variation of the distribution of the energy vs. the average frequency and the events vs. amplitude with the load,and got the distribution law of the amplitude vs. the average frequency.We used the 2-D location technology, Through comparative analysis found that the technique could perform well on the multi-crack.(3)We used acoustic emission technique on prestressed concrete cable-stayed beam experiment, Through the distribution of AE parameters vs. time, we found the cracking time and the unstable failure point that the two features could be used as the warning of crack appearance and failure of the elastic support system engineering structures.Through comparative analysis of the distrution between energy and average frequency,we found the AE signals released by the beam carried amounts of low-frequency waves after steel yielding and amounts of high-frequency as well as high-energy waves when the beam was failure.We applied the 2D planar location and linear location on the beam simultaneously, and found itcould describe and locate the crack propagation on the longitudinal direction along with the beam and local part well, Respectively.