Professor and head, Department of Mechanical Properties, Institut für Material- und Festkörperforschung, Kernforschungszentrum Karlsruhe, Karlsruhe,
Pages: 21 Published: Jan 1982
The life fraction rule (LFR) is used to calculate the lifetime of materials subjected to stress and temperature ramp loading. The solutions for the individual nonstationary temperature and stress loading conditions can be applied to predict also the lifetime of structures loaded by superimposed ramps solely on the basis of normal “iso”-stress rupture data. The concept is applied to tensional stress and temperature cycling as well. Without any fitting procedure, the results of calculations are compared with those delivered by experiments performed on Zircaloy tension specimens. A variety of results from burst tests on Zircaloy cladding tubes conducted at different laboratories is compared as well. The agreement between calculations and experiments is in general surprisingly good. A modified Monkman-Grant relationship was applied to predict the failure strain of Zircaloy-4 subjected to tensile rupture test at load as well as at temperature ramp conditions, respectively. As compared with the peculiarities of the problem, the agreement between experiments and calculations is encouraging.
zirconium, nuclear industry, lifetime prediction, prediction of failure strain, life fraction rule, modified Monkman-Grant relationship, stress and temperature ramps, stress and temperature tensional cycling, superimposed stress and temperature loading, high-temperature failure, Zircaloy-4
Paper ID: STP37061S