Modelling rebar in reinforced concrete in Impetus

Reinforced concrete is often used in defensive structures. To calculate weapon effects against such structures, it is important to accurately represent the reinforced concrete in numerical models. However, with a complete description of both the concrete and the reinforcement, the time needed for computations increases drastically. Fortunately, the finite element code Impetus includes a built-in rebar model. The model is simplified but reduces the computational time significantly.
The purpose of this report is to compare the simplified built-in rebar model to a full 3D model of the rebar. Only impact problems are analyzed in this study.
When comparing the two models, the residual velocity after perforation and the visual damage on the rebar are similar. This indicates that the inbuilt rebar model gives reasonable results. As expected, the computational time using the built-in model is significantly shorter compared to using a full 3D model of the rebar.
In conclusion, the built-in rebar model in Impetus gives a representative result of impact calculations on reinforced concrete. Its shorter computational time makes it a sensible alternative to full 3D modelling.
We have only considered concrete plates with a small amount of reinforcement. We expect the difference in computational time to be even larger for concrete plates with more reinforcement.