PSI - Issue 57

Luca Vecchiato et al. / Procedia Structural Integrity 57 (2024) 518–523 Vecchiato L et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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3. Conclusions The Peak Stress Method (PSM) is an engineering approach used in the fatigue design of welded structures. The weld toe and weld root are modelled as sharp V- notches with null tip radius (ρ = 0) and rather coarse 2D or 3D FE meshes are adopted to estimate the Notch Stress Intensity Factors (NSIFs) by means of the singular, linear elastic peak stresses calculated at the V-notch tip. Using the averaged Strain Energy Density (SED) fatigue criterion, an equivalent peak stress range is defined as a fatigue damage parameter. Recently, the PSM has been extended to multiaxial variable amplitude local stress situations. In the present investigation the VA formulation of the PSM has been used for the fatigue strength assessment of a full-scale arc-welded attachment on an aluminium alloy beam. The PSM proved fairly accurate, with fatigue strength estimations resulting slightly on the safe side both in constant amplitude and in variable amplitude fatigue. References Campagnolo A, Vecchiato L, Meneghetti G (2022) Multiaxial variable amplitude fatigue strength assessment of steel welded joints using the peak stress method. Int J Fatigue 163:107089. https://doi.org/10.1016/j.ijfatigue.2022.107089 Lazzarin P, Livieri P, Berto F, Zappalorto M (2008) Local strain energy density and fatigue strength of welded joints under uniaxial and multiaxial loading. Eng Fract Mech 75:1875 – 1889. https://doi.org/10.1016/j.engfracmech.2006.10.019 Lazzarin P, Tovo R (1998) A notch intensity factor approach to the stress analysis of welds. Fatigue Fract Eng Mater Struct 21:1089 – 1103. https://doi.org/10.1046/j.1460-2695.1998.00097.x Meneghetti G, Campagnolo A (2020) State-of-the-art review of peak stress method for fatigue strength assessment of welded joints. Int J Fatigue 139:105705. https://doi.org/10.1016/j.ijfatigue.2020.105705 Meneghetti G, Campagnolo A, Visentin A, et al (2022) Rapid evaluation of notch stress intensity factors using the peak stress method with 3D tetrahedral finite element models: Comparison of commercial codes. Fatigue Fract Eng Mater Struct. https://doi.org/10.1111/ffe.13645 Meneghetti G, Lazzarin P (2007) Significance of the elastic peak stress evaluated by FE analyses at the point of singularity of sharp V-notched components. Fatigue Fract Eng Mater Struct 30:95 – 106. https://doi.org/10.1111/j.1460-2695.2006.01084.x Miner MA (1945) Cumulative damage in fatigue. J Appl Mech 12:159 – 164 Palmgren AG (1924) Die Lebensdauer von Kugellagern. Zeitschrift des Vereines Deutscher Ingenieure 68:339 – 341 Smith IFC, Hirt MA (1992) Fatigue behaviour of aluminium beams with welded attachments. In: Proceedings of the “5th INALCO '92”, International Conference on Aluminium Weldments Vecchiato L, Campagnolo A, Meneghetti G (2023) The Peak Stress Method for fatigue lifetime assessment of fillet welded attachments in steel subjected to variable amplitude in-phase multiaxial local stresses. Int J Fatigue 169:107482. https://doi.org/10.1016/j.ijfatigue.2022.107482