Residual Strength and Fatigue Lifetime of ... - Solid Mechanics

high growth rate of G (see Figure 4.7), but approaching the end of 500 cycles with decreasing
G, crack increment becomes smaller. The simulation with qG=q=0.05 follows the reference
simulation with good agreement, but the simulation with qG=q=0.2 shows again less accuracy.
(a)
(b)
Figure 4.8: Crack length vs. number of cycles for control parameters (a) qG=q = 0.05 and (b)
qG=q = 0.2.
Figure 4.9 presents the phase angle vs. number of cycles. The same conclusion may be drawn
upon the accuracy of the simulation using the cycle jump method and the two control parameters
qG=q=0.05 and qG=q=0.2.
(a)
(b)
Figure 4.9: (a) Mode- mixity phase angle vs. number of cycles for the reference analysis and
the analyses with qG=q=0.05 and qG=q=0.2 as control parameters.
To measure the computational efficiency of the cycle jump method for analyses with different
control parameters, the ratio R is introduced:
N jump
R (4.11)
N
ref
where Njump is the number of jumped cycles and Nref is the total number of cycles in the reference
72