PSI - Issue 16

24 Andrzej Kurek et al. / Procedia Structural Integrity 16 (2019) 19–26 6 Andrzej Kurek, Justyna Koziarska, Tadeusz Łagoda, Karolina Łago da / Structural Integrity Procedia 00 (2019) 000 – 000 c” is lower in terms of the absolute value for finite defo rmations. The fatigue plastic deformation coefficient for finite deformations is also lower ′′ than the fatigue plastic deformation coefficient ′ .

Fig. 2. Changing the dependence of tension amplitude on the plastic deformation from small deformations model to finite deformations.

Table 1. The comparison of the materials analysed and their materials constants Material E , GPa R m , MPa n' n''

K' , MPa

K'' , MPa

11NiMnCrMo55

210

852 110 667 929 435 597 597 635 929

0.085

0.105 0.168 0.143 0.157 0.236 0.211 0.241 0.352 0.124

1129

1339

1100 Al HSB55

69

0.11

157

215

210 214 214 210 210 204 214

0.122 0.137 0.208 0.185 0.211

1170 1369

1389 1622 1210 1491 1645 2769 1492

N-A-Xtra 70 (2)

St37 St52

992

1231 1357 2383 1240

St52-3

X10 CrNi 18 8

0.33

N-A-Xtra 70 (X-tra)

0.099

Table 2. The comparison of the cyclic fatigue properties of the materials analysed Material b b'' ′ , MPa ′′ , MPa c 11NiMnCrMo55 -0.067 -0.081 1194.90 1417.50

′ ′′ 1.483 1.339 0.511 0.293 0.777 0.728 1.464 1.357 0.457 0.421 0.567 0.507 0.452 0.410 0.255 0.241 1.213 1.116

c''

-0.750 -0.718 -0.609 -0.749 -0.482 -0.527 -0.496 -0.406 -0.687

-0.744 -0.606 -0.608 -0.746 -0.476 -0.509 -0.489 -0.402 -0.683

1100 Al HSB55

-0.089 -0.075 -0.105 -0.100 -0.097 -0.105 -0.131 -0.070

-0.097 -0.087 -0.121 -0.112 -0.109 -0.118 -0.138 -0.088

156.74 1134.00 1465.9 843.16 1106.7 1150.8 1474.92 1281.86

171.93 1331.40 1741.96 980.12 1295.70 1331.40 1619.76 1555.78

N-A-Xtra 70 (2)

St37 St52

St52-3

X10 CrNi 18 8

N-A-Xtra 70 (X-tra)

Furthermore, the relative change of fatigue parameters was also calculated. The analysis of the results presented indicates that the relative change of fatigue limit coefficients at tension-compression for small deformations and finite deformations is positive and on average it amounts to 16.08%, whereas it is the highest for steel N-A-Xtra 70