The Research Of Damage Identification In Reinforced Concrete Beam Based On Acoustic Emission

Concrete material, a kind of low cost construction material, has been widely used in buildings, bridges, ports, DAMS and airports, etc. Because of its high self-weight and difficult being repaired, reinforced concrete structure’s failure may bring a loss of lives and properties. Therefore, the damage assessment, safety evaluation for existing structures and the real-time monitoring technology for new structures are of great practical significance. Compared with traditional detection methods, acoustic emission has a strong sensitivity with damaged concrete structure, it can monitor the working state of the concrete structure real-timely, and warn the structural damage timely.We carry out an experiment of two reinforced concrete beams under four-point bending, and use acoustic emission test system to monitor the destruction of the beam, to explore the relationship between the AE parameters and damages by analyzing the AE data.1. We carry out the experiment of two reinforced concrete beams under four-point bending. Through analyzing the AE signal of all failure process, we find the range of amplitude and frequency under different failure mechanisms.2. We get the AE activity function and damage curve by analyzing the damage process based on damage mechanics and AE rate process theory. The study find that the AE rate parameter has different changing rules at different loading stages, we can use it to discern and warn the early damage.3. According to the fractal theory, we calculate the correlative dimension by using MATLAB. Through analyzing the changing rule of the correlation dimension combined with the AE parameters and damage curve; we can put forward the rate threshold value based on the rule of "max-min" before destruction and identify the working state of beam.