3.1 FE Debond Analysis
The creep-fatigue crack growth tests explained in Chapter 2 were
simulated using the ABAQUS debond analysis option [43]. Figure 3
shows the FE mesh of the C(T) specimen, consisting of 1 4,964
two-dimensional (2-D) plane strain second-order solid elements with
reduced integrations (CPE8R). For loading and unloading, the static
structural analysis option, *STATIC, was used and for creep-hold, the
quasi-static analysis option, *VISCO, was used with the user-subroutine
CREEP. The FE analysis was performed using the large geometry change
option (NLGEOM in ABAQUS). To simulate crack growth, the debond option
in ABAQUS was used using the *FRACTURE CRITERION, TYPE=CRACK LENGTH
keyword option. The debond
analysis method is schematically described in Fig. 4, where the
experimentally-measured crack extension data were given as a function of
time using the crack length
criteria. The crack advances according to the crack length input by
releasing nodes. Outputs were the
load-line displacement, crack tip stress and strain fields.