Synergetic Analysis Of Damage Identification Of Concrete Materials Based On Acoustic Emission Technology

Due to its wide applicability and price advantage,concrete materials are now widely used in infrastructure such as civil buildings,bridge projects,and airports.However,due to its large weight and difficulty in repairing,the loss of property and life caused by the destruction of the concrete structure is difficult to estimate.Therefore,it is of great engineering practical significance to evaluate the damage and safety of concrete structures and introduce real-time monitoring technology for buildings under construction.Acoustic emission technology can produce a very rapid reflection on material damage and damage,so as to make up for the shortcomings of traditional detection methods,and can realize real-time monitoring of detected objects and effective early warning of structural damage in construction and service.In order to investigate the influence of initial defects on the internal damage of concrete under uniaxial compression,cube test blocks with different initial defects were fabricated for cubic compression test.In order to study the evolution law of cracks in concrete,four reinforced concrete beams with the same specifications were studied.The three-point loading and four-point loading bending failure tests were carried out respectively,and the whole process of loading failure was monitored by the acoustic emission system and the strain system.The counting rate of the acoustic emission events that can describe the damage process of the cubic test block was obtained.Histogram,ringing count rate-time histogram,acoustic emission event rate and strain-time correlation curve,and duration proportional distribution map,acoustic emission b value change diagram,damage factor change characterizing the damage characteristics of reinforced concrete beams Figure.Finally,an exploratory analysis of the data obtained in the experiment was conducted in a synergistic view.The main research work and achievements of the thesis are as follows:(1)Perform uniaxial compression test on cube test blocks with different initialdefects,synchronously collect press load,acoustic emission characteristic parameters and concrete surface strain data,and analyze the variation law of acoustic emission characteristic parameters during cubic uniaxial compression,combined with events The relationship between the count rate and the strain time is studied to study the influence of initial defects on the acoustic emission phenomenon.(2)Four reinforced concrete beams of the same specification were produced,and the bending failure tests under four-point loading and three-point loading were respectively carried out.The acoustic emission source signals in each loading and failure stage of the test beam under different loading modes are qualitatively discriminated by the duration of acoustic emission,and the acoustic emission amplitude is statistically analyzed by using the G-R formula used to quantify the magnitude-frequency in seismology.The variation law of the amplitude under different loading modes is obtained.Finally,the damage evolution model based on the cumulative number of acoustic emission is used to quantitatively describe the damage process.(3)Based on the theory of synergy,select the number of acoustic emission events as the order parameter,use the Lanvegin equation model to establish the order parameter equation of the concrete acoustic emission process,and solve the order parameter equation with the adiabatic elimination principle,so as to explain through the synergistic viewpoint Concrete acoustic emission phenomenon.Then,the synergistic phenomena of the reinforced concrete beam subjected to bending failure process are described and analyzed in three aspects: disorder,order,self-organization and self-similarity,so as to explore the feasibility of using synergistic theory to study the acoustic emission phenomenon of concrete.accuracy.