PSI - Issue 38
A. Chiocca et al. / Procedia Structural Integrity 38 (2022) 447–456
453
A. Chiocca et al. / Structural Integrity Procedia 00 (2021) 000–000
7
10 7
10 3
∆ σ n = √ 3 ∆ τ n
10 6
Expected N f
10 5
10 2 Nominal stress range - ∆ σ n (MPa)
A
10 4
A
10 4
10 7
10 5
10 6
Experimental N f
Bending as welded
K = 5 . 2
Run out
Bending stress relieved Torsion as welded Torsion stress relieved
A
K = 7 . 8
R = − 1
10 1
10 7
10 5
10 6
Number of cycles to break-through - N f
Fig. 7: Nominal stress range over number of cycles to break-through for pure bending and pure torsion fatigue loading in as-welded and stress relieved conditions
4. Results
400
353
Bending R = − 1
346
335
293
328
200 Findley - FI (MPa) 300
267
318
307
238
272
255
Max. relative di ff erence ≈ 8%
236
108
121
134
178
191
164
Nominal stress range (MPa)
400
Torsion R = − 1
200 Findley - FI (MPa) 300
241 313
231 305
226 299
215 286
205 275
196 264
186 253
Max. relative di ff erence ≈ 27%
188
202
231
282
215
250
262
Nominal stress range (MPa)
stress relieved
as-welded
Fig. 8: Findley’s critical plane factor over nominal stress range for pure bending and pure torsion loading in as-welded and stress relieved conditions
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