Test Bed for Quantitative NDE

Abstract

The ARPA/AFML Interdisciplinary Program for Quantitative Flaw Definition has demonstrated a number of new techniques for quantitatively sizing flaws, as are reported elsewhere in these proceedings. This paper describes the progress that has been made during the past year on a test bed program to assemble and demonstrate these techniques in a single integrated measurement system that will extend them from the idealized geometries that have been considered thus far to geometries that are a better approximation to those that are found in real parts. The basic system consists of a Data General Eclipse S/200 Minicomputer, a multiaxis microprocessor controller, a Biomation A/D converter, an immersion tank, and a contour following system with six degrees of freedom. The operation of the mechanical system with regard to its accuracy and repeatability will be described. In addition, a review of the conceptual design of the test bed system and experimental results for a number of different flaw geometries will be included. The Test Bed includes a piezoelectric array transducer and associated electronics. The array system will be used both for the imaging of flaws and the gathering of scattering data to use in other flaw characterization algorithms. The success of this portion of the program depends to a large extent on the availability of a suitable array transducer. Some difficulty has been met in obtaining such a transducer and the system design has been slightly modified as a result. The modified system will be described along with a review of the electronic system and an update on its current status. The extended data gathering capability of the system has been demonstrated with several diffusion bonded samples containing spherical and spheroidal voids. The noise associated with these signals is chiefly due. to the grain scattering and varies in amplitude over a wide range. The effects of this noise on the accuracy of the Inverse Born Approximation has been analyzed and the results will be summarized

    Similar works