Crack Paths 2006

Figure 6. Residual stresses [MPa], theoretically calculated, against x [m] and T [K].

Table 4. Prediction as number of cycles and kilometers to failure for a tank wagon

railway axle fracture with residual stresses

Initial crack size c [mm]

4.5

6

7.5

Cycles (kilometers) to fracture with residual stresses due to a welded layer o d = 5 m mat T = 400K

(21.349˜61070) (18.41˜610007)

9.3˜106

(53900)

Cycles (kilometers) to fracture (with residual stresses due to a welded layer o d = 5 m mat T = 600K)

(95.97˜115006)

(18.65˜215007)

7.0˜106

(40450)

Cycles (kilometers) to fracture (with residual stresses due to a welded layer o d = 5 m mat T = 800K)

(74.32˜410006)

(15.90˜51007)

5.4˜106

(31350)

Cycles (kilometers) to fracture (with residual stresses due to a welded layer o d = 5 m mat T = 1000K)

(53.73˜210006)

(74.58˜215006)

4.4˜10

6

(25200)

C O N C L U S I O N S

Any residual stresses in a railway axle will dramatically reduce the number of cycles

(kilometres) to failure. In real life the railway axle will not fracture as soon as predicted

in this paper for a few reasons:

x the wagons will not always be filled (sometimes they have to be emptied);