PSI - Issue 3

Alberto Lorenzon et al. / Procedia Structural Integrity 3 (2017) 370–379 A. Lorenzon et al. / Structural Integrity Procedia 00 (2017) 000–000

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large amount of data provided by CFD, a scaling procedure on the basis of climatic data of a fatigue load spectrum evaluated from a reference mean wind velocity (see Flamand et al. (1996); Repetto and Torrielli (2017)) could allow a reduction of computational effort. In the framework of time-domain approach, it is opinion of the authors that the use of a turbulence model that allows to resolve only the most dynamically important fluctuating scales without the need to resolve inertial scales could provide optimal results. This is possible, for example by means of hybrid models such as PANS model by tuning the ratios of the unresolved-to-total kinetic energy and dissipation parameters. Further studies could therefore be carried out to assess the application of hybrid models like PANS models to structures of interest for civil engineering. Another possible future development could be the calculation of fatigue damage based on the time-domain cycle counting of stress cycles obtained from time series from CFD models with different approaches (LES and RANS). In fact, as shown above, both models are able to capture the flow irregularities, and although the LES method provides the most accurate results they are also much more computationally expensive, and their ability to capture more irregularities could be of little significance for the purpose of the accumulation of damage. In conclusion, on the basis of the results of the present review, it is possible to assume that the CFD methods can be successfully used for the purpose of fatigue calculations of steel structures subject to fluctuating wind action. Their use could allow a reduction of the costs of analysis by avoiding, at least in a preliminary phase, the use of expensive models in the wind tunnel. Finally, the authors wish to emphasize the fact that the latest requirements from standards in terms of fatigue safety make it necessary to thicken the links between different engineering disciplines. In fact, CFD or wind tunnel analyses and consequent fatigue analyses have not only an impact on the project but also on the production and quality control phases. Acknowledgement The authors wish to thank Dr Alessandro Catanzano, for kindly providing us his valuable industrial perspective, and Dr Marco Colussi for the useful observation and suggestions. References Bampton, M.C.C., Craig, JR., R.R., 1968. Coupling of substructures for dynamic analyses. AIAA J. 6, 1313–1319. doi:10.2514/3.4741 Cluni, F., Gusella, V., Ubertini, F., 2007. A parametric investigation of wind-induced cable fatigue. Eng. Struct. 29, 3094–3105. doi:10.1016/j.engstruct.2007.02.010 Colussi, M., Berto, F., Meneghetti, G., 2017. Fatigue assessment of welded joints in large steel structures: a modified nominal stress definition, in: Proceedings of the International Fatigue Conference - Fatigue 2017, Downing College, Cambridge, UK July 2017. Davidenkov, N.N., Shevandin, E., Wittmann, F., 1946. The Influence of Size on the Brittle Strength of Steel. Int. J. Appl. Mech. 68. Dowell, E.H., Hall, K.C., 2001. Modeling of fluid-structure interaction. Annu. Rev. Fluid Mech. 33, 445–490. doi:10.1146/annurev.fluid.33.1.445 Ducros, F., Nicoud, F., Poinsot, T., 1998. Wall-adapting local eddy-viscosity models for simulations in complex geometries. Conf. Numer. Methods Fluid Dyn. 1–7. Durbin, P.A., 1991. Near-wall turbulence closure modeling without “damping functions.” Theor. Comput. Fluid Dyn. 3, 1–13. doi:10.1007/BF00271513 Elshaer, A., Aboshosha, H., Bitsuamlak, G., El Damatty, A., Dagnew, A., 2016. LES evaluation of wind-induced responses for an isolated and a surrounded tall building. Eng. Struct. 115, 179–195. doi:10.1016/j.engstruct.2016.02.026 Flamand, O., Bietry, J., Barre, C., Germain, E., Bourcier, P., 1996. Fatigue calculation on the roof sustaining cables of a large stadium in Paris. J. Wind Eng. Ind. Aerodyn. 64, 127–134. doi:10.1016/S0167-6105(96)00087-6 Fröhlich, J., von Terzi, D., 2008. Hybrid LES/RANS methods for the simulation of turbulent flows. Prog. Aerosp. Sci. 44, 349–377. doi:10.1016/j.paerosci.2008.05.001 Girimaji, S.S., 2006. Partially-Averaged Navier-Stokes Model for Turbulence: A Reynolds-Averaged Navier-Stokes to Direct Numerical Simulation Bridging Method. J. Appl. Mech. 73, 413. doi:10.1115/1.2151207 Hanjalic, K., 2005. Will RANS Survive LES? A View of Perspectives. J. Fluids Eng. 127, 831. doi:10.1115/1.2037084 Hanjalić, K., 2004. Closure models for incompressible turbulent flows. Lect. Notes Von Kármán Inst. 1–75. Holman, D.M., Brionnaud, R.M., Abiza, Z., 2012. Solution to industry benchmarck problems with the Lattice-Boltzmann code XFlow. Eur. Congr. Comput. Methods Appl. Sci. Eng. (ECCOMAS 2012) 22. Argyropoulos, C.D., Markatos, N.C., 2015. Recent advances on the numerical modelling of turbulent flows. Appl. Math. Model. 39, 693–732. doi:10.1016/j.apm.2014.07.001