Research On Technology Of On-line Quantitative Nondestructive Testing For Steel Pipe Based On Phased Array Ultrasound Imaging

As a typical component of cylindrical components,steel pipes have been widely used in important fields such as national economy and national defense construction.Because of the diversification of the use environment and the influence of alternating stress,the steel pipe is prone to defects and failure during use,causing serious economic losses and even casualties.Therefore,the quality of steel pipes must be monitored using non-destructive testing techniques.After years of development,non-destructive testing technology has many different methods and methods,and ultrasonic non-destructive testing technology has become one of the most widely used method in the field of non-destructive testing because of its safety,rich information and easy combination with signal processing technology.In fact,ultrasonic nondestructive testing has traditional and phased array ultrasound.Because phased array ultrasound has the advantages of acoustic beam flexible control,dynamic focusing and large aperture imaging,it has become the mainstream direction in recent years,and it has been gradually applied in automated online imaging,but its wider application also faces challenges such as detection reliability,real-time and resolution,and near-end/surface defect detection capabilities.Based on the above background,funded by the National Natural Science Foundation of China,I propose to carry out on-line quantitative non-destructive testing technology for steel tubes based on phased array ultrasound imaging on this dissertation.On the basis of understanding the research status and development trend of related technologies at home and abroad,and clarifying the principle and requirements of phased array ultrasonic imaging detection of steel tubes,the phased array ultrasonic imaging based on mechanical and electronic composite scanning and the near end face defects of steel pipes are mainly carried out.The research on key technologies such as online phased array ultrasonic imaging detection solves the problems of image stitching and blind spot detection in multi-scan mode.At the same time,combining phased array ultrasonic nondestructive testing with mechatronics technology,a set of on-line quantitative non-destructive testing system based on phased array ultrasonic imaging was developed,and relevant experimental research was carried out to verify the feasibility and effectiveness of the proposed technology.The main research work is reflected in:In the first chapter,I discussed the important role of steel pipe in the national economy and the significance of research on phased array ultrasound imaging detection technology,and clarified the research status and development trend of phased array ultrasound imaging detection technology and application.In the second chapter,we carried out a research on phased array ultrasonic imaging detection technology for steel tube Near-End defects.I have established and solved the wave equation in the cylindrical coordinate system,and completed the calculation,simulation and characteristic analysis of the radiated sound field based on the spatial impulse response.I clarified the basic principle of phased array beam deflection focusing,and carry out beam synthesis and control research based on laminated structure.At the same time,I analyzed the influence of acoustic effects on the resolution of phased array ultrasound imaging,and clarified the requirements for incident beam for different damage detection.In the third chapter,I achieved a phased array ultrasound imaging technology based on mechanical and electronic composite mode.Using mechanical scanning to scan the global wide-area and electronic scanning local fine-grained imaging strategy,on the basis of completing the mechanical scan,I use multi-resolution analysis of common parts of two adjacent position electronic scanning imaging results using two-dimensional wavelet transform,and weight the corresponding details and reconstructing.After that,we achieved seamless splicing of ultrasound imaging results and a wide range,high efficiency and fine imaging.In the fourth chapter,we carried out a research on phased array ultrasonic imaging detection technology for steel tube Near-End defects.Based on applying the L-R deconvolution algorithm to eliminate signal aliasing and realize high-precision estimation of ultrasonic echo signal transit time,determine the near end region by the rotation invariance of the end echo.The change law of the transit time in the detection gate of the area is monitored by using the end face wave as a reference to identify the near end face defect.It effectively solves the problem of excessive blind area of the phased array ultrasonic imaging detection technology,and lays a necessary technical foundation for the ultrasonic imaging of the whole tube.In the fifth chapter,through the research of the above theory and technology,I organically combined the phased array ultrasonic imaging technology and mechatronics technology.Based on completing the design and development of related software and hardware modules,I develop an online quantitative non-destructive testing system for steel pipes based on phased array ultrasonic imaging.The system integration is realized by PXI communication bus.At the same time,the system is used to carry out relevant experimental research,which confirms the feasibility and effectiveness of the technology and system developed in this paper.In the sixth chapter,summarizes the research content of this paper and looks forward to further research in the future.