Fatigue behavior of cold roll-formed rail profiles for rack structures

Abstract

In large companies, warehouse logistics usually include shuttle pallet carriers that are responsible for the transportation of various goods and products. These shuttles run along steel rails, which are usually produced from thin metal sheets that are cold roll-formed into the desired section. These shuttles also work 24 hours a day, 7 days a week, so the rails are very sensitive to fatigue phenomena, caused by the cyclic loading of the moving shuttles, moreover, cracks due to material fatigue have already been observed in these types of rails. In addition, the competitiveness of the European industrial sector is pushing the design of these profiles to lower thickness requirements, which further increases concerns about their fatigue performance. Within this background, the FASTCOLD European project has been carried out, whose research plan consists in developing fatigue design rules for the mentioned applications, which are not covered by existing Eurocode 3 rules, which only addresses thick hot-rolled sections. Experimental fatigue testing has been carried out backed by numerical simulations of these tests. A new fatigue setup has been developed to generate representative fatigue cracking to the shuttle cyclic loads. Numerical simulations of the cold roll-forming fabrication process are also being carried out to determine the importance of the residual stresses in the fatigue life of the rail. With the experimental data obtained from fatigue testing backed by numerical simulations, important contributions are made to the design codes (e.g. Eurocode 3) in dealing with the fatigue design of such critical details.