PSI - Issue 38

Tuomas Skriko et al. / Procedia Structural Integrity 38 (2022) 393–400 Skriko et al. / Structural Integrity Procedia 00 (2021) 000 – 000

400

8

5. Conclusions This study increased the knowledge on the fatigue strength of laser-dressed non-load-carrying fillet weld joints made of UHSS. Based on the experimental measurements and tests, along with statistical and numerical analyses, the following conclusions can be drawn: • Laser dressing enhances the local UHSS fillet weld toe geometry compared to as-welded condition but the residual stresses in the vicinity of weld toe areas are generally on tension after the laser treatment. • The applied global stress ratio has a minor effect on fatigue strength of laser-dressed UHSS fillet weld joints. • The experimental fatigue strength results of laser-dressed non-load-carrying fillet welds are at lower level compared to corresponding TIG-dressed joints with same material, loading and weld type but, however, the calculated characteristic FAT values for laser-dressed joints with nominal and structural hot-spot stress methods are close to the IIW recommendations for FAT classes of TIG dressing (NB: apply up to R p 0.2 = 900 MPa). • The 4R method is a suitable approach for fatigue assessment of laser-dressed UHSS weldments. Acknowledgements The authors wish to thank Business Finland for the funding in the “Arktiset rakenteet” project. In addition, appreciations are expressed to JAMK University of Applied Sciences and Dr. Tomi Nieminen for their contribution to the execution of experimental research work and numerical analyses. References Ahola, A., 2020. Stress components and local effects in the fatigue strength assessment of fillet weld joints made of ultra-high-strength steels. Doctoral thesis. Lappeenranta: Lappeenranta University of Technology. Ahola, A., Muikku, A., Braun, M., Björk, T., 2021. Fatigue strength assessment of ground fillet-welded joints using 4R method. International Journal of Fatigue, 142, 105916. Ahola, A., Skriko, T., Björk, T., 2020. Fatigue strength assessment of ultra-high-strength steel fillet weld joints using 4R method. Journal of Constructional Steel Research, 167, 105861. Ahola, A., Skriko, T., Björk, T., 2019. Experimental investigation on the fatigue strength assessment of welded joints made of S1100 ultra-high strength steel in as-welded and post-weld treated condition. In: Zingoni, A. (Ed.), Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019). Cape Town, South Africa, 2-4 September 2019. pp. 1254-1259 Baumgartner, J., Bruder, T., 2013. An efficient meshing approach for the calculation of notch stresses. Welding in the World, 57(1), pp. 137-145. Björk T., Ahola A., Skriko T., 2018. 4R method for consideration of the fatigue performance of welded joints – Background and applications. In: Chan, S.-L., Chan, T.-M., Zhu, S. (Eds.), Proceedings of the Ninth International Conference on Advances in Steel Structures (ICASS 2018). Hong Kong, China, 5-7 December 2018. pp. 1159-1168. Braun, M., Wang, X., 2021. A review of fatigue test data on weld toe grinding and weld profiling. International Journal of Fatigue, 145, 106073. EN 10149-2, 2013. Hot rolled flat products made of high yield strength steels for cold forming – Part 2: Technical delivery conditions for thermomechanically rolled steels. Brussels: European Committee for Standardization (CEN). EN ISO 16834, 2012. Welding Consumables - Wire electrodes, wires, rods and deposits for gas shielded arc welding of high strength steels - Classification (ISO 16834:2012). Brussels: European Committee for Standardization (CEN). Fricke, W., 2012. IIW Recommendations for the Fatigue Assessment of Welded Structures by Notch Stress Analysis. Cambridge: Woodhead Publishing Limited. Haagensen, P. J., Maddox, S. J., 2013. IIW Recommendations on Methods for Improving the Fatigue Strength of Welded Joints. Cambridge: Woodhead Publishing Limited. Hobbacher, A. F., 2017. Recommendations for Fatigue Design of Welded Joints and Components. 2nd ed. Cham: Springer International Publishing. Macdonald, K. A., 2011. Fracture and Fatigue of Welded Joints and Structures. 1st ed. Cambridge: Woodhead Publishing Limited. Marquis, G. B., Barsoum, Z., 2016. IIW Recommendations for the HFMI Treatment. Singapore: Springer Singapore. Niemi, E., Fricke, W., Maddox, S. J., 2018. Structural Hot-Spot Stress Approach to Fatigue Analysis of Welded Components. Singapore: Springer Singapore. Nykänen, T., Björk, T., 2016. A new proposal for assessment of the fatigue strength of steel butt-welded joints improved by peening (HFMI) under constant amplitude tensile loading. Fatigue and Fracture of Engineering Materials and Structures, 39(5), 566-582. Skriko, T., 2018. Dependence of manufacturing parameters on the performance quality of welded joints made of direct quenched ultra-high-strength steel. Doctoral thesis. Lappeenranta: Lappeenranta University of Technology. Skriko, T., Ghafouri, M., Björk, T., 2017. Fatigue strength of TIG-dressed ultra-high-strength steel fillet weld joints at high stress ratio. International Journal of Fatigue, 94(1), pp. 110-120. Yildirim, H. C., 2015. Review of fatigue data for welds improved by tungsten inert gas dressing. International Journal of Fatigue, 79, pp. 36-45.