Study On Static Damage Of Concrete Beam Bridge Based On Acoustic Emission Theory

The acoustic emission technology as a new dynamic nondestructive testing technology,because of its real-time,development of internal defects and crack monitoring of the dynamic structure,has been widely used in the detection of structural damage location and damage degree evaluation of structure.In this paper,the acoustic emission technology and its principle to carry out the concrete structure of the acoustic emission characteristics based on the test.On the relationship between AE parameters and concrete was investigated.The main research contents and results are as follows:(1)according to the time between sensor observations of P wave arrival time value theory limit and delay signal arrival time value theory limit,according to the time difference,the characteristics of geometrical arrangement and monitoring sensor,through 2 kinds of difference to solve the model theoretical limit,the formation of time difference analysis table,so that the arrival time difference value the acoustic wave delay signal recognition method based on the exclusion of delay signals of the sensors.(2)The type specimen simulation of prestressed concrete box girder structure in the bending shear stress under the condition of injury,mainly to monitor the shearing surface of the acoustic emission signal,20 selected time range for different levels of stress and acoustic emission events,according to the regression analysis of the acoustic emission activity function,the change regularity of acoustic emission rate parameters with the stress level of the three stage.(3)The prestressed concrete box girder damage monitoring with acoustic emission technique,process selection of box girder damage in a number of acoustic emission events as the research object,using the plane linear time difference method,the crack acoustic emission sources are located;the qualitative changes of the three stage use rate parameters to predict damage stage of prestressed concrete box girder.(4)To carry out the experimental study on the characteristics of concrete beam acoustic emission,found the cumulative number of acoustic emission with stress level is divided into linear development,steady growth and instability in three stages.On the basis of changes proposed-the number of acoustic emission events and the stress level of mathematical expressions using three order polynomial model,probability density get the function,evolution of concrete beam damage equation.By comparing with the empirical formula calculation,analysis,proof and effective application of damage evolution equation.