PSI - Issue 39

Daniela Scorza et al. / Procedia Structural Integrity 39 (2022) 503–508 Author name / Structural Integrity Procedia 00 (2019) 000–000

508

6

10 7

0 7

0 7

Conservative

Conservative

Conservative

0 6

0 6

10 6

N f,exp [cycles]

τ xy,a / σ x,a 0 ∞ 0.5 1.02.0 β =0° β =90° (b)

τ xy,a / σ x,a 0 ∞ 0.5 1.02.0 β =0° β =90° (a)

τ xy,a / σ x,a 0 ∞ 0.5 1.02.0 β =0° β =90° (c)

0 5

0 5

10 5

0 4

0 4

10 4

10 4

10 4

10 4

N f,cal [cycles] 10 5 10 6

10 7

N f,cal [cycles] 10 5 10 6

10 7

N f,cal [cycles] 10 5 10 6

10 7

f ,exp N , vs theoretical one, 3 1 2400 V mm = ; (b) for

f ,cal N , estimated through the present criterion by employing the fatigue limits

Fig. 3. Experimental fatigue lifetime,

3 7 9 09 cr V . E mm = + and (c) from the experimental data.

obtained: (a) for

6. Conclusions

In the present paper, the Carpinteri et al. criterion is used in conjunction with the max area -parameter model by Murakami and Yanase, to estimate the fatigue strength of naturally defective high strength steels under multiaxial loading. To such an aim, an experimental campaign available in the literature, consisting in multiaxial fatigue tests performed on AISI 4140 steel specimens, is analysed to evaluate the criterion accuracy. The results, in terms of fatigue lifetime, are compared with the experimental data by considering different values of the fatigue strengths (both computed and experimentally evaluated). It can be concluded that the use of the specimen gauge region volume for the computation of the fatigue limits gives the best results, since 77% of the data fall within the scatter band 3 and the mean square error is equal to 2.31. References Carpinteri, A., Ronchei, C., Scorza, D., Vantadori, S., 2015. Critical Plane Orientation Influence on Multiaxial High-Cycle Fatigue Assessment. Physical Mesomechanics 18: 348-354. Khameneh, M.J., Azadi, M., 2018. Evaluation of high-cycle bending fatigue and fracture behaviors in EN-GJS700-2 ductile cast iron of crankshafts. Engineering Failure Analysis 85, 189-200. Kiessling, R., Lange, N., 1978. Non-metallic inclusions in steel. London, UK: Metals Society. Lambrighs, K., Verpoest, I., Verlinden, B., Wevers, M., 2010. Influence of non-metallic inclusions on the fatigue properties of heavily cold drawn steel wires. Procedia Engineering 2, 173–181. Machado, P.V.S., Araújo, L.C., Soares, M.V., Araújo, J.A., 2020. Multiaxial fatigue assessment of steels with non-metallic inclusions by means of adapted critical plane criteria. Theoretical and Applied Fracture Mechanics 108, 102585. Murakami, Y. 2002, Metal Fatigue: Effects of Small Defects and Nonmetallic Inclusions. Oxford, UK: Elsevier Science Ltd. Vantadori, S., Carpinteri, A., Luciano, R., Ronchei, C., Scorza, D., Zanichelli, A., Okamoto, Y., Saito, S., Itoh, T., 2020. Crack initiation and life estimation for 316 and 430 stainless steel specimens by means of a critical plane approach. International Journal of Fatigue 138, 105677. Vantadori, S., Ronchei, C., Scorza, D., Zanichelli, A., Araújo, L.C., Araújo, J.A., 2022. Influence of non-metallic inclusions on the high cycle fatigue strength of steels. International Journal of Fatigue 154,106553. Walat, K., Łagoda, T., 2014. Lifetime of semi-ductile materials through the critical plane approach. International Journal of Fatigue 67, 73-77. Yakura, R., Matsuda, M., Sakai, T., Ueno, A., 2016. Effect of inclusion size on fatigue properties in very high cycle region of low alloy steel used for solid-type crankshaft. R and D: Research and Development Kobe Steel Engineering Reports 66, 20-24. Yanase, K., Endo, M., 2014. Multiaxial high cycle fatigue threshold with small defects and cracks. Engineering Fracture Mechanics 123, 182–196.