A new constitutive model for steel fibre reinforced concrete subjected to dynamic loads

The use of steel fibre reinforced concrete (SFRC) in protective structures has gained worldwide interest due to its superior mechanical characteristics. At present, hydrocode material models have been frequently used to simulate the dynamic behaviour of SFRC subjected to impact and blast loads. However, as these material models are developed for normal concrete, much effort is required for model calibration, and their other drawbacks, such as the neglect of shear dilation and the inappropriate consideration of strain-rate effect, may lead to inaccuracies in numerical predictions. In this study, a new constitutive material model is developed for SFRC, in which the damage evolution, shear dilation and strain-rate dependent material properties are properly taken into account. The new material model could accurately capture the mechanical behaviours of SFRC (i.e. strain hardening and softening in both compression and tension) with simple input parameters. It is then incorporated into the commercial finite element code LS-DYNA to simulate the structural behaviour of SFRC components under various loading conditions. The effectiveness and accuracy of the new material model are validated against the reported experimental results.