System for computer analysis of stress-strain curves

A system for recording and processing of data obtained in tensile tests is described. The electronics (hardware) consists of signal amplifiers (load and elongation), digital voltmeters with binary code decimal output, serializer, and incremental magnetic tape recorder. The operation sequence is controlled by a system of relays, time delays, and an electronic clock. The computer program calculates not only the typical mechanical properties such as yield stress, ultimate stress, and uniform and total elongation, but also more sophisticated properties such as strain-hardening coefficient and Reed-Hill coefficient, which are difficult to obtain by other means. The computer output is in the form of tabulated data and plotted curves. The system has been used in over 300 tests of Zircaloy and aluminum samples. Most of the tests were done on irradiated ring samples cut from the cladding of boiling water reactor fuel rods, but also tube- and plate-type samples have been tested. There was good agreement between the computer-generated values and the values calculated by conventional methods