2022 6th International Conference on Mechanics, Mathematics and Applied Physics (ICMMAP 2022)
Prof. Weiwei Zhang, Dongguan University of Technology, China

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I was graduated from Jinan University with with a Ph.D. The Thesis was entitled Studies on Crack Identification Methodology for Structure Based on Mode Analysis and Stress Wave. After graduating, I went to work at Taiyuan University of Science and Technology. In July 2021, I was transferred to Dongguan University of Technology. I presided over 2 research projects of NSFC: 1) Dynamic response and damage identification method of nonlinear stress wave due to Microscopic defects under moving loads (2012.1-2014.12); Studies on bifurcation theory of nonlinear stress wave due to microscopic defects and its application (2019.1-2022.12), and 2 Natural Science Foundations of Shanxi Province: 1) Research on the propagation of guided Waves in welded Pipes and duffing oscillator identification Method (2012.1-2013.12); Nonlinear mixing characteristics and Application of stress waves induced by defects in rail (2018.12-2020.12). In past, I published 1 monograph entailed Pipe Ultrasonic Guided Wave and Chaos System Inspection Technology, more than 50 academic papers, ant 5 authorized invention patents. (more)


Research Areas: 

① Solid mechanics

② Structure health monitoring

③ Stress wave


Speech Title:

Studies on Chaos system inspection of weak ultrasonic guided wave 

弱超声导波的混沌检测方法研究


Abstract: 

Ultrasonic guided wave (UGW)-based damage detection technology is a method of exciting ultrasonic  along the length of the pipeline, and the UGW are reflected when they encounters defects such as cracks, welds, and corrosion. Pipeline defect can be identified by analyzing the amplitude and time of the defect echo. In recent years, as the service environment of pipeline becomes more and more complex, for the small defects in the early stage of pipeline damage, the defect echo is usually weak signal under strong noise. In order to improve the detection efficiency of small defects in the pipeline, a weak guided wave identification method based on the parameter sensitivity of the Duffing chaotic system is proposed. The parameters of Duffing system are determined as the following: the driving force frequency is determined according to the frequency of the signal-to-be-detected; 2) the damping is an arbitrary constant; 3) the amplitude of the driving force is changed, and the bifurcation diagram of the Duffing system with it was calculated. 4) The critical value of the Duffing detection system was determined at the critical point of system transition from periodic state to chaotic state. After determination of Duffing inspection system, the signal-to-be-detected is added on the driving force, and the weak ultrasonic guided wave signal could be detected by using the chaotic phase transition features. Finally, two chaotic systems are proposed to identify the amplitude identification and arriving time of the defect echo, and the size and location of pipeline defects are identified based on them.