The creep curves for three different
measuring procedures are shown in Fig. 5B. The curves for the two
creep programs are shown separately for each imposed stress level,
so they can be compared to the unique specimen curves. According
to the results it follows that the total amount of the creep strain
after 500 seconds does not deviate significantly between the different measuring procedures. However, some minor differences are
observed in the transitional area between the curves for the unique
specimen and multiple level curves. This is to be expected as the
material previously exposed to creep at a lower stress level had
already experienced a certain amount of primary creep and is
therefore exhibiting softer behaviour in the region of primary
creep at higher stress levels. The level of creep after 500 seconds
is approximately equal for all three measuring procedures.