PSI - Issue 2_B

Daniel F. C. Peixoto et al. / Procedia Structural Integrity 2 (2016) 1904–1911 Author name / Structural Integrity Procedia 00 (2016) 000–000

1907

4

For homogeneous, isotropic elastic materials the direction of cracking propagation can be calculated using the maximum tangential stress criterion as 2 2 2 2 1 2 2 3 4 8 cos 9 II I I II I II K K K K K K               (1) The Richard/Henn criterion, Richard et al. , (1991), Henn et al. , (1988), was considered to calculate the equivalent stress intensity factor ( K V ), as: (2) It was defined that the process of increasing the crack will be repeated until the maximum mixed mode equivalent stress intensity factor reaches the threshold or reaches a value that can be considered that is within the unstable crack propagation zone. 4. Results As results, in the next paragraphs the obtained crack path and the evolution of the stress intensity factor will be shown in Figures 5 to 11. In Table 2 the obtained crack propagation angles are listed. These angles are measured relatively to the horizontal plane. In this case the calculation process ended when the maximum mixed mode equivalent stress intensity factor reached a value considered in the unstable propagation zone, see Figure 11, which implies that the crack will growth rapidly until it reaches the wheel surface, in this case, considering the propagation angle the crack will reach the wheel tread. In Figure 12 the maximum value of K V recorded for each crack length is represented as a function of crack length. 2 K K  2 1 6 2 2 I V I II K K  

a) Initial 10mm straight crack path

b) 12mm crack path

c) 14mm crack path

d) 16mm crack path

e) 18mm crack path

f) 20 crack path

Figure 5: Wheel crack propagation path.

Table 2: Wheel crack propagation angles. crack length [mm] left crack tip angle [deg] right crack tip angle [deg] 10 67 -58 12 -58 62 14 -53 -60 16 61 68 18 -58 -43 20 -54 59 left tip