Damage Evaluation Method Of Reinforced Concrete Based On Ultrasonic Guided Wave

Reinforced plays a important role in civil engineering construction. It is the main structural component of the force. The interfaces between concrete and rebar always delaminate because corrosion and fatigue loads impact. Effective dynamic monitoring methods is deficient in reinforced damage identification.There are many advantages of ultrasonic guided wave,such as high sensitivity, wide monitoring surface and receiving the information signal containing the whole of the contact surface and the inner reinforcement.However,the ultrasonic guided wave signal has frequency dispersion and multi-modal characteristics to impact monitoring results.Ultrasonic guided wave signal recognition reinforced concrete damage is significant The main contents are as follows:Firstly, establish a rebar defect ultrasonic guided wave propagation model by ANSYS software respectively for different defect. Solve mechanics by transient analysis module in ANSYS. Get defect echo waves in each group working conditions and analyzed their fractal dimensions respectively. According to the length and depth of the defect, the relationship between the fractal dimension obtained with the degree of defect by MATLAB.Secondly, test steel rebar by using ultrasonic guided waves. Time difference location method is used to find the defect echo waveform in each condition signals, and analyzes the different degrees of damage signals using fractal dimension theory. It achieved similar results with simulations and verified the validity of damage identification ultrasonic guided wave signal with fractal dimension method.Thirdly, the ultrasonic guided wave technique is adopted to monitor the different levels reinforced concrete corrosion damage evolution process. Signals are processed to obtain the variation value of the signal energy before and after corrosion. Wavelet packet energy spectrum is obtained to determine the damage evolution process and its time-frequency distribution is achieved. According to the analysis results, the characteristics of waveform, types of damages, and frequency distribution of different damage phases are collected.Through these studies, we can draw the following conclusions:The reasonable ultrasonic guided wave experiments can effectively detect defects on rebar. The fractal dimension method can accurately and effectively quantify the different degrees of reinforcement damage. for concrete reinforcement corrosion damage, the signal energy analysis and wavelet packet energy can also analyze the degree of corrosion of diagnosis.