PSI - Issue 5

Przemyslaw Strzelecki et al. / Procedia Structural Integrity 5 (2017) 832–839 Przemyslaw Strzelecki et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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Table 1. Properties of tested materials.

Material S u [MPa] S y [MPa]

C45+C 42CrMo4 S355J2+C

1.4301 S235JR

AW-6063 T6

826 647 21.1

1172 1095 32.7

806 678 24.7

623 269

409 240

200 167

HRC HRB

78

63

39 79

HB (calculated from HRC or HRB acc. PN-H 04357 (1993))

232

308

251

147

106

Table 2. Properties of materials from literature.

Material S u [MPa] S y [MPa]

1045 from Aviles et al. (2013)

SUS630 from Mohd et al. (2015)

2024 T351 from Mayer et al. (2013)

870 726

1073 1056

473 364 141 120

HV

390 370

HB (przeliczone z HV wg [11])

278

Examples of the characteristics obtained with the use of the verified models were summarized in Fig. 3. A S-N diagram estimated from the experimental data (full line) was applied for reference, according to the methodology as per ISO-12107 (2003) (model I). The quantities that were obtained by the individual models are presented in Table 3, Table 4 and Table 5. When analysing Table 3, Table 4 & Table 5 it can be noticed that the values of m slope estimated from the experiment are much larger than the value assumed in method III, except for the notched samples case. In method II it may be stated that the variability range of this quantity equalled from 9.1 to 15.3. This fact caused the differences between the experimental value and the value calculated according to method II to be smaller than in case of method III. The case was reverse only for material SUS630. The m slope value was comparable only for the notched samples. For evaluating N k number of cycles, the values obtained by method III are smaller than the experiment result. In method II, adopting the fixed value of 10 6 turned out to be approximate to the experimental value.

a)

b)

S355J2+C

S235JR

Failure Run out Model I Model II Model III

Failure Run out Model I Model II Model III

150 200 250 300 350

300 350 400 450 500 550 600

Stress amplitude [MPa]

Stress amplitude [MPa]

1e+04

5e+04

2e+05 5e+05

2e+06 5e+06

1e+04

5e+04

2e+05 5e+05

2e+06 5e+06

Number of cycles N

Number of cycles N

Fig. 3 Fatigue data with S-N curves for different models a) S235JR, b) S355J2+C

Table 3. Values estimated for tested materials.