| The pipeline structures are ubiquitous in daily socitey,and are indispensable strategic structures of industrial production,people’s life and military defense.From mining and transportation of underground oil and natural gas,offshore oil and natural gas and other important energy,to the residents’ home tap water pipes,heating pipes,sewage pipes,gas pipes,they deeply cover production and life in all aspects.The greater the capacity,the greater the responsibility.The pipeline structures have so excellent engineering qualities that they often serve in tough work conditions,vulnerable to all kinds of factors such as aging,impact,liquid or gas corrosion and environmental changes,resulting in pipeline surface or internal injury,as time passes injury continues to expand,weaking structural bearing capacity,seriously even cause huge engineering accidents and casualties.In order to ensure the smooth and safe operation of pipeline structure,regular maintenance is essential.Ultrasonic guided wave technology is the modern rise of the new nondestructive testing technology,since it has fast detection,monitoring of large span,small destruction of scene,capability of online real-time monitoring,and many other advantages,has been widely used in the detection of all kinds of structure,especially for regular engineering components such as pipelines has a great application prospect.This paper first summarizes the domestic and foreign pipeline structural health monitoring and damage identification and localization techniques,and then deduce the ultrasonic guided wave theory,the propagation process summed up various modes of ultrasonic guided wave pipeline structure,then the structure guided evolutionary programming algorithm of reasoning pipeline and various modes of wave dispersion curves,considering various factors to select incentive signal analysis of ABAQUS simulation and experimental verification,the guided wave damage identification and positioning of the various forms of damage ultrasonic positioning scheme pipeline under various working conditions,and under study.Under the excitation of the pipeline structure,a lot of modes and modes of guided waves will be generated,some of which are needed in the process of damage identification and localization.Based on the two dimensions of the axial location and the circumferential orientation of the pipeline damage location,the paper designs the two positioning schemes.A scheme is L(0,2)model of longitudinal and circumferential positioning of dual mode Lamb second mode method,single point excitation and multi-point receiving sensor network layout and the probability density method of elliptic path based positioning sensor by the scheme;another is torsion wave T(0,1)single mode positioning method the whole week,torsional excitation and multi-point receiving sensor network layout and positioning method of elliptic sensing probability density path based on the scheme.The above two schemes are used for different damage modes such as free pipe and fluid pipeline,such as different working conditions,hole damage and groove damage.Then the difference between the two methods was compared.Finally,the experimental platform is built to verify the reliability of the simulation results and the correctness of the positioning scheme.In this paper,the research methods and conclusions of ultrasonic guided wave damage identification and location of pipeline structures have important reference significance to the research of guided wave detection of similar engineering structures. |
