Scientific Employee, Institut für Werkstoffkunde 1, Universität Karlsruhe,
Head of Laboratory for Near Service Loadings, Institut für Werkstoffkunde 1 Universität Karlsruhe,
Prof. Dr.-Ing, Head of the Institut für Werkstoffkunde 1, Universität Karlsruhe,
Pages: 15 Published: Jan 2003
Start-stop and load change processes of combustion engines result in inhomogenous and instationary temperature fields, which induce cyclic mechanical loadings, e.g., in solid and cooled turbine blades and vanes. The present study shows results of so-called complex thermal-mechanical fatigue“ (CTMF) tests carried out with a two specimen testing system in order to simulate the interaction of the “hot“ outer and the “cold“ inner side of a cooled turbine blade and the influence of superimposed mechanical loadings. The test pieces were made from the austenitic steel AISI 316 L. Specimen 1 represents the “hot“ and specimen 2 the “cold“ side of the component, respectively. Both specimens were loaded by individual thermal cycles. The mechanical interaction of the “hot“ and the “cold“ side is simulated firstly by keeping the total strains of both specimens at identical values. Secondly, in order to simulate external loadings such as centrifugal forces at turbine blades, the sum of the forces at both specimens is given as a function of time. The influence of dwell times at the maximum temperatures as well as of superimposed forces on the cyclic deformation and the cyclic creep behavior of the two specimen system is presented and discussed.
thermal fatigue, thermal-mechanical fatigue, austenitic steel, AISI 316 1, cyclic creep
Paper ID: STP11442S