A time-dependent damage operator approach to thermo-mechanical fatigue of Ni-resist D-5S

Turbocharger Structural Integrity

“…As described by Nagode et al [8], the prediction of low cycle fatigue failure of the turbine housing has to take into account the effects of creep as well as plastic deformation. This significantly complicates the analysis and as the authors have pointed out, further material data from biaxial testing at elevated temperature is required to validate the multi-axial behaviour of the material model.…”

Identification of material parameters from low cycle fatigue, thermomechanical fatigue and creep tests for damage prediction of thermomechanically loaded Ni-resist Type D-5S

“…Temperature and total strain and stress response on a cylindrical specimen for four stabilised TMF cycles were measured next. In Figure 2, one of these cycles is depicted, while others can be seen in Nagode et al 13 In-phase TMF tests have been Dashed lines show previous study by Nagode et al 13 Symbols T, s, e and D stand for temperature, stress, strain and damage, respectively. Index e denotes experimentally obtained values whereas index s denotes simulated values.…”

“…However, simulation results highly depend on the chosen set of material parameters [7][8][9][10][11][12] which in addition can be determined from a variety of tests. 3,[11][12][13][14][15][16] Therefore, it is crucial to choose the right test for the determination of the most appropriate set of material parameters.…”

“…The material parameters had to be set so as to optimally describe this cycle, and the search for the optimal set of material parameters with different approaches is highlighted in this article. Furthermore, we wanted to predict the accumulated damage in the specimen and compare this prediction with a previous prediction of the same TMF cycle by Nagode et al 13 Due to high thermal and mechanical loads, both fatigue and creep properties of the material had to be considered. 13,14,17 Fatigue and creep damages were calculated separately by Palmgren-Miner and Robinson rules.…”

A method for long-term creep–rupture strength prediction based on a small sample of experimental results, smoothed bootstrapping and time–temperature parameters

“…In these situations, the determination of master curves can only be based on an interim experimental data set (e.g. 9-20 experimental results, that is 3-5 stress levels at 3 or 4 test temperatures [34,35]). These tests are mostly carried out over a relatively short period of time, i.e.…”