Nöldgen, M.M.NöldgenRiedel, W.W.RiedelThoma, K.K.ThomaFehling, E.E.Fehling2022-03-122022-03-122013https://publica.fraunhofer.de/handle/publica/3806732-s2.0-84879937076This paper is a contribution to the material description of Ultra High Performance Concrete (UHPC) at high-speed dynamic loading conditions. Based on a series of Hopkinson-Bar experiments, dynamical material parameters such as the Tensile Strength, Young's Modulus and Fracture Energy are determined at high strain rates of 102 s-1. A comparison with the results of these parameters for normal and high strength concretes leads to a qualitative and quantitative description of UHPC at high strain rates. Differences in macroscopic strain-rate-effects occur due to a significantly reduced amount of the moisture effect (reduced capillary pores) on the one side and a different relation of aggregate to grout strength for UHPC on the other side (section 1). Based on the experimentally determined Fracture Energy and Stress-Crack-Opening- Relation a material model for UHPC at high strain-rates is postulated by extending the established RHT concrete damage model with a new fracture me chanical damage law (section 2). Numerical hydrocode simulations of the Hopkinson-Bar Experiments are presented to proof the evidence of the concrete model for a one-dimensional wave propagation problem. Furthermore a series of impact experiments on rebar reinforced UHPC plates with more complex three-dimensional wave propagation show a satisfying accuracy of the new fracture mechanic concrete model even for more complex failure mechanisms from cracking of the concrete to perforation of aircraft engine missiles at high strain rates (section 3).en620conference paper