PSI - Issue 47

Teresa Morgado et al. / Procedia Structural Integrity 47 (2023) 882–887 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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From the results of the meshes refinement study was observed that the mesh refinement did not significantly influence the SIF results; all tests present an acceptable error (SIF error <1%); the difference between the errors of test 1 and test 8 is about 0.4%, which shows the impact between the less and the most refined mesh. The simulation results for Test 2, with and without contacts was observed that the software can simulate the experimental model (without contacts) with very satisfactory results; the model without contacts presents a J-Integral error < 8.2% and a FIT error <4.2%; and the model without contacts offers the advantage of faster modelling of the SENB model, thus avoiding solving numerical problems arising from the contacts established between the rigid and deformable bodies. From the results of the 2D study using XFEM was observed that the refinement of the meshes did not influence the crack propagation results, and the damage criterion is the most critical parameter in the crack propagation results. From the elements that were used to perform the 3D XFEM study with fatigue, calculated the energy dissipated by the plastic in each one, it was observed that the elements E80 and E1163 provide ΔS IF values close to those obtained experimentally, i.e. between the range [23; 32] [MPa √mm ]. 4. Conclusions From the 2D numerical simulation study was concluded that with the crack length of 10 mm is possible to obtain values identical to values . The refinement of the meshes did not influence the crack propagation results. Moreover, the model without contacts presented an accepted error value; nevertheless, it is bigger than the error obtained with the model with contact. It was also concluded from a 2D study with fatigue that ΔSIF Num values obtained by the Conventional Method are similar to experimental ones. The 3D numerical simulation study concluded that Contour 1 should not be despised; furthermore, when the number of contours increases, SIF and Integral J values do not differ significantly. Moreover, when the number of contours increases, SIF and Integral J values also tend to increase. It was also concluded that XFEM Method is more accurate than the Conventional method. In conclusion, conventional and extended finite element methods adequately evaluate the stress intensity factor and J-Integral. Nevertheless, XFEM produces better results than the Conventional method. Acknowledgements The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT.IP) for its financial support through the grant UIDB/00667/2020 (UNIDEMI). References Abaqus 6.14 - Theory Guide. Dassault Systèmes, 2014. Anderson T. L., Fracture Mechanics: Fundamentals and Applications. CRC press, 2005. Infante, V., Branco, C. M., Brito, A. S., Morgado, T. L., 2003. A failure analysis study of cast Steel Railway Coupling Used for Coal Transportation. Engineering Failure Analysis, Elsevier Science Ltd.,10-4, 475-489. A. Kobayashi, S. Chiu e R. Beeuwkes, “A numerical and experimental investigation on the use of J- integral”, Engineering Fracture Mechanics, vol. 5, n.o 2, pp. 293 – 305, 1973. Morgado, T., 2016. Failure of steel coupling used in railway transport. In: Makhlouf, A.S.H., Aliofkhazraei, M. (Eds.), Handbook of Materials Failure Analysis with Case Studies from the Aerospace and Automotive Industries. UK, pp. 449 – 469. Morgado T. L. M., 2015. Fatigue Life Extension Study in Cast Steel Railway Couplings Used in Freight Trains. International Journal of Mechanical. Engineering and Applications. Special Issue: Structural Integrity of Mechanical Components, vol. 3, No. 2-1, pp. 1-6. Shih C. F., Moran B., Nakamura T., 1986. Energy release rate along a three-dimensional crack front in a thermally stressed body. International Journal of Fracture, vol. 30, n.o 2, pp. 79 – 102. Xue C., He A., Yong H., Zhou Y., 2013.Crack tip opening displacement in a linear strain hardening material. Mechanics of Materials, vol. 66, pp. 21 – 34. Zhu X.-K.,. Joyce J. A, 2012. Review of fracture toughness (G, K, J, CTOD, CTOA) testing and standardization. Engineering Fracture Mechanics, vol. 85, 1 – 46.