Dynamic behaviour of austenitic stainless steel used for rebars in tension

Thanks to their intrinsic durability, austenitic stainless steels are currently used as rebars in several strategic reinforced concrete constructions subjected to severe environmental conditions in order to increase their service life. Furthermore, these structures (offshore structures, highway bridges, harbor structures, high-rise buildings and many others) are often subjected to particular accidental limit states as impact, explosion or seismic loading. The effects of strain rate on stainless steels have consequently gained much attention in the last years because there is a lack of knowledge in design of reinforced structures under these accidental dynamic loads. This paper will describe the dynamic behavior of X5CrNi18-10 austenitic stainless steels used for rebars subjected to tension loading. Tensile tests were performed on round specimens at different strain-rate levels, using a Split Hopkinson Tension Bar device, a hydro-pneumatic apparatus and an universal electro-mechanic machine respectively for high, intermediate and static strain rates. The experimental data were utilized to obtain stress-strain relationships under different strain-rate conditions and results are finally compared with existing formulations, providing dynamic properties of stainless reinforcing steel. The experimental results are finally used to obtain the material parameters of the constitutive relationships to predict accurately the flow behaviour.