【作者】 白世武；

【导师】 李午申；

【作者基本信息】 天津大学 ， 材料加工工程， 2010， 博士

【摘要】 全自动相控阵超声波检测系统是超声波检测技术与计算机技术相结合的种新型检测方法,与其它超声检测方法相比,具有高效、准确及相对直观的显著特点。本课题研制的管道环焊缝相控阵超声检测系统主要应用于大口径长输管道全自动焊接设备完成的焊缝质量检测,尤其对层间未熔合、坡口边缘未熔合等缺陷具有很强的检出能力,在对口间隙一定的情况下,也可用于半自动焊焊缝检测。本文根据超声理论和管道环焊缝的焊接工艺,建立了相控阵超声检测的数学模型；通过对相控阵超声的聚焦、偏转和近场区特性的理论计算和试验研究,制定出了相控阵超声检测工艺方案；根据管道施工环焊缝焊接缺陷检测标准,开发出具有较高开放性和适应性的系统控制软件,该软件包括：上位机检测显示软件、FPGA(Field-Programmable Gate Array)工艺控制程序、下位机的过程控制程序以及数据高速采集和传输软件；开发出了满足工程需求的硬件控制系统,包括：相控阵超声波发射/接收系统、高速数据采集系统和管道环焊缝爬行扫查系统；研究了环焊缝焊接缺陷评价方法,并开发出相关软件；经多次进行现场实验和工业应用测试,证明本课题研制的全自动相控阵超声检测系统性能稳定。本课题的创新点包括：(1)建立长输管道环焊缝不同壁厚、不同坡口形式相控阵超声检测数学模型,将相控阵扫查技术应用于长输管道环焊缝检测领域；(2)根据超声理论,建立了相控阵超声聚焦、晶振片数和晶片间的延时计算模型；设计系列试验试块,模拟出覆盖管道环焊缝相控阵超声传感器的聚焦、偏转、近场区长度等特性,为控制相控阵超声的硬件、软件提供依据；(3)根据长输管道环焊缝焊接无损检测标准,建立了管道环焊缝缺陷智能识别模型和缺陷识别方法,为实现缺陷的智能化判别奠定基础。更多还原

【Abstract】 Automatic Phased Array Ultrasonic Testing (APAUT) system is combined ultrasonic measurement technology with computer technique. Comparing with other ultrasonic testing methods, APAUT is a new non-destructive evaluation (NDE) technology that has the characteristics of high detecting efficiency and can accurately give the image of defect. APAUT system developed in the thesis is mainly used in pipeline grith welding and aimed to evaluate the welding quality of long-distance large-diameter pipeline welded by automatic welding equipment. It has strong ability to test the defect, especially for non-fusing welding interlayers and groove fringe. It can also be used to evaluate the quality of semi-automatic welding in the condiction of corresponding gap fixed.On the basis of ultrasonic theory and pipeline girth welding technique, the mathematic model for phased array ultrasonic testing is bulided in this thesis. Based on the theory calculation and experiment research on ultrasonic focusing, deflection and the near field characteristic, the phased array ultrasonic testing process is formulated. According to the testing standard of welding defect in pipeline construction with girth welding, the software control system with high open source and good adaption is developed, in which the measurement display software in upper computer, Field-Programmable Gate Array (FPGA) technique control programme, the process control programme and data acquisition and transimission software in lower computer are included. Based on the project requirement, the hardware control system is developed and fabricated, in which phased array ultrasonic transimission/reception system, high speed data acquisition system and crawl-scanning system for pipeline girth welding is involved. The welding defect evaluation method for pipeline girth welding is studied and corresponding software is developed. The result of experiment and application shows that the performance of APAUT systme developed in this paper is stable. The innovation of the research include:(1) to establish the mathematic model of phased array ultrasonic testing for long-distance pipeline girth welding with various wall thickness, different groove. (2) based on ultrasonic theory, to conclude the calculation model of phased array ultrasoinic focusing, number of crystal piece and time-delay among the crystal pieces; a series of testing block designed to modulate the focusing, deflecting and near field length corresponging to pipeline girth welding phased array ultrasonic sensors for designing and developing the hardware and software of phased array ultrasonic. (3) According to the non-destructive testing standard of long-distance pipeline girth welding, intelligent defect identification model and classification method established for pipeline girth welding, so as to realize the intelligent identification of defect.更多还原