Identification of strain-rate sensitivity parameters of steels with an inverse method

Since the second half of the past century, research in the automotive industry focused on vehicle performance, environmental compatibility, and safety improvement. Increasing interest about passive safety and the ever stricter regulations, both in the US and EU, pushed towards more reliable models of the vehicle behaviour and, to achieve this, to a deeper insight into material behaviour. For what concerns crash simulations, one of the most critical uncertainty relates to the influence of the loading speed on the material mechanical properties. This influence can be accounted by means of the strain-rate sensitivity that is substantial for most materials. Strain-rate sensitivity of low-carbon steels, such as the deep-drawing steels of most automotive body, is very well known.