Fig. 1
Crack propagation angle according to the second mode of SIFs (A) KII > 0 (B) KII < 0.
Fig. 2
(A) Crack tip in an arbitrary contour, (B) J-integral area.
Fig. 3
Computational procedure of the fatigue crack growth developed program.
Fig. 4
Cracked plate with four holes and one edge crack.
Table 1
Mechanical properties of aluminium 7075-T6 [51]
| Property | Value in metric unit |
|---|---|
| Modulus of elasticity, E | 72 GPa |
| Poisson's ratio, υ | 0.33 |
| Yield strength, σy | 469 MPa |
| Ultimate strength, σu | 538 MPa |
| Fracture toughness, KIC | 3,288.76 MPa |
Fig. 5
Initial generated mesh (A) Ansys Workbench, (B) developed program.
Fig. 6
Crack growth path: (A) Ansys Workbench, (B) developed program, (C) FMM backscattered electron macroscope (BEM) [46]. FMM, fast multipole method.
Fig. 7
Crack growth trajectory (A) maximum principal stress (developed program), (B) maximum principal stress (Ansys), (C) minimum principal stress (developed program), (D) minimum principal stress (Ansys). All units in MPa.
Fig. 8
KI and KII for cracked plate with four holes.
Fig. 9
Comparison for the stress contour distribution in y direction (A) developed program, (B) Ansys, and (C) FMM BEM [52]. All units in MPa. FMM, fast multipole method.
Fig. 10
Geometry and boundary condition of the three holes’ single edge crack plate.
Table 2
Configurations of the three holes’ single edge cracked plate
| Specimen No. | Length of crack, a (mm) | Crack position, b (mm) |
|---|---|---|
| 1 | 25.4 | 152.4 |
| 2 | 38.1 | 127 |
Fig. 11
Initial mesh of the three holes’ single edge cracked plate in (A) Ansys, (B) developed program.
Table 3
Mechanical properties of the three holes single edge cracked plate [22]
| Properties | Metric units value |
|---|---|
| Modulus of elasticity, E | 205 GPa |
| Poisson's ratio, υ | 0.3 |
| Yield strength, σy | 516 MPa |
| Fracture toughness, KIC | 730 MPa |
| Threshold SIF, Δkth | 80 MPa |
| Paris’ law coefficient, C | 1.2 × 10−11 |
| Paris law exponent, m | 3 |
Fig. 12
Predicted crack growth path for specimen 1, (A) developed program, (B) Ansys.
Fig. 13
Specimen 1, crack growth trajectory (A) Ansys simulation (B) developed program (C) experimental [53], (D) numerical results [54], (E) numerical results [22], (F) numerical results [15].
Fig. 14
Dimensionless SIFs for specimen 1. SIFs, stress intensity factors.
Fig. 15
Predicted crack growth path for specimen 2, (A) developed program, (B) Ansys.
Fig. 16
Specimen 1, crack growth trajectory, (A) Ansys simulation, (B) developed program, (C) experimental [53, 55], (D) numerical results [54].
Fig. 17
Dimensionless SIFs for specimen 2. SIFs, stress intensity factors.