Figs.7 shows the comparisons for the initial cycle between LCF testing
result from the SSFS specimen and the predicted results from the MTP FE
specimens with varied scaling factors at 600 °C for FV566. The predicted
average strain-stress responses in the loading direction,
,
were extracted from the parallel gauge length regions. Taking the design
of l 0/d0 = 1.0 (MTP-1) as
an example, it can be observed from Fig.7a that the
hysteresis shape obtained from the numerical FE model changes with the
increase of scaling factor (e.g., β increases from 2.0 to 4.0),
while the predicted hysteresis curve is in good agreement with SSFS data
until β reaches to 4.0. As for the other two MTP samples shown in
Figs.7b and 7c, the geometry constraint effect mitigates caused by the
increase of l 0/d0 , leading
to an excellent agreement of hysteresis responses with SSFS data using
relatively smaller values of scaling factor, for example, β = 3.2
for MTP-2, and β = 2.7 for MTP-3, respectively. It can be clearly
concluded here that the tentative scaling factors could result in
different hysteresis responses for the MTP specimen until an appropriate
value occurs. This value is regarded as the finalized scaling factor as
tabulated in Table 2, which is capable to provide the excellent
predicted hysteresis response and agree well with the experimental SSFS
data.