DEFECT ASSESSMENT USING CONFORMABLE ARRAY DATA

Abstract

The conformable array data acquisition system consists of the array, the data acquisition and analysis hardware, and the data acquisition and analysis software. The following decisions were made in the development of the system. Array design decisions include the following: (a) The flexible array board will be approximately 8 by 12 inches square with the active coil section confined to a smaller 6-inch-square section at the center of the board. The outer edges of the board will be used for switching and other circuitry. (b) The diameter of the array coils will be approximately 0.375 inch (9.5 mm). Data acquisition strategy includes: (a) The corrosion spots will be mapped by successive interrogations of the active section of the array board. Approximately 10,000 samples will be acquired for each coil. The 10,000 readings will be averaged to produce one lower-noise value for each coil. This will be repeated for each coil in the array in a sequential manner. The total corrosion image for the sector will be built from the individual coil data. (b) Corrosion larger than the operational portion of the array board will be measured using a grid technique. Uniquely identified areas in the grid will overlay a corroded area, and data collected for each area will be connected by the display and assessment software to form a composite image for the corroded area. (c) Defect assessment will be invoked on the corrosion image by ''boxing'' selected areas on the color contour map. Software decisions consisted of selecting the appropriate LABVIEW modules running in a Windows XP operating system to obtain the required functionality. This third quarterly report of the project presents the activity and conclusions reached to date. Specifically, the design of the conformable array was completed and work was started on obtaining the data acquisition hardware. Southwest Research Institute (SwRI) and Clock Spring{reg_sign} staff met at the SwRI facilities in June 2003 to discuss the project. The Clock Spring representative was given the latest version of the data acquisition and analysis software for evaluation. Comments were received.