详情

原文传递 Testing of In-Service Bridges Using Automated Ultrasonic Testing Methods.

题名：	Testing of In-Service Bridges Using Automated Ultrasonic Testing Methods.
作者：	Boone, S.; Cohen, J.; Sauser, P.
关键词：	In-service bridges, Automated Ultrasonic Testing (AUT), Ultrasonic testing (UT), Programmable software
摘要：	This goal of this project was to develop a prototype automated ultrasonic testing (AUT) system for detecting weld defects (flaws) in steel bridge members. Identifying the location, size, and extent of weld defects can be critical for ensuring bridge safety. Current automated ultrasonic testing (AUT) practice relies primarily on visual inspection for detecting cracks but is not capable of detecting subsurface weld defects that may develop into crack under service loading. Other technologies such as conventional ultrasonic testing (UT) and radiographic testing (RT) can detect subsurface flaws, but are used primarily during the bridge fabrication process because the technologies are difficult to apply to in-service bridges. For RT, the geometry of in-service welds often preclude the proper alignment of the source and film, and required safety precautions for RT can limit practical application. For UT, the method requires a high level of expertise to implement and results can have uncertain resolution and accuracy because the method relies on an inspector’s ability to effectively scan critical areas manually and interpret relevant indications. The present study sought to investigate the effectiveness of AUT to improve the resolution, accuracy, and reliability of inspections. AUT systems are typically composed of an ultrasonic transducer coupled with some kind of electronically-driven positioning vehicle for moving the transducer in a controlled and trackable manner. In this way the position and orientation of the transducer is controlled, such that scanning critical areas is ensured and test repeatability is increased. AUT systems may employ conventional ultrasonic transducers or phased array transducers. Phased Array Ultrasonic Testing (PAUT) methods can produce better defined and quantified defect indications as compared with conventional UT because of its beam-steering capabilities. AUT is used as an established and proven technology in defense, nuclear, and pressure vessel applications, but has yet to be fully employed on steel bridges. The primary objective of this project was to research and develop the mechanical and electrical equipment needed for an AUT system that could be applied for in-service bridge inspection. An industry scan of available scanning sensor architectures, data acquisition hardware, and analysis software was completed to inform the selection and design of the final inspection system. Based on this industry scan, a cost-effective prototype system based on a low-cost ($500) X-Y plotting printer system, with its inherent precision movement and programmable software, was developed. Preliminary testing was completed using the AUT prototype on a steel plate to make initial refinements to the coupling apparatus used to ensure contact between the UT probe and test surface.
报告类型：	科技报告