Damage Imaging Method Based On Guided Wave Energy Flow In Metallic Plates

The defects in the structure can be detected quickly and intuitively by the detection method based on the damage imaging technology of the ultrasonic guided wave.Thus,the imaging technology has the important development prospects in the field of Structural Health Monitoring or Nondestructive Testing.Most of the damage imaging technology is able to realize the accurate positioning of the damage in the structure but hard to evaluate its shape information accurately.Moreover,concerning the effects caused by the contact transducer sensor array needing for extra adhesives in the experiment,this article will realize the non-contact automatic scanning detection for plate structure by the Scanning Laser Doppler Vibration so as to extract the signal data of the ultrasonic guided wave containing the damage characteristics.Next the damage imaging method based on the Lamb wave energy flow for the effective detection of the different kinds of defects neighboring information in the plate is studied.The main research work is as follows:Expounding the characteristic of the Lamb wave propagation in the aluminum plate structure and the energy flow of interaction between the Lamb wave and the different kinds of defects to provide a new method of the inspection for nondestructive testing technology in plate-like structure.The index of the damage imaging and the theory of the Moore neighbor tracing algorithm are studied for providing theoretical basis on quantitative detection for the shape of the damage by the Lamb wave energy flow imaging method.The characteristic of the Lamb wave propagation is studied based on the finite element Numerical simulation for the metallic aluminum plate structure,obtaining guided wave signal data containing damage information,and analyzing the energy distribution and energy flow of the Lamb wave with the data,then detecting andevaluating for the defects of different types,the defects of different depth and several defects in the metallic aluminum plate based on Moore neighbor tracing algorithm such as the information of location size and neighbor to realize the visualization of the damage.By constructing experimental platform of damage detection in the metallic aluminum plate,signal parameters are collected in the detection area based on using Scanning Laser Doppler Vibration.The Lamb wave energy flow damage imaging method is applied to the detection for the defects in the metallic aluminum plate,and then compared with the results of the numerical simulation,it validates the feasibility and effectiveness of nondestructive testing with this imaging method.