Numerical investigation of concrete subjected to compressive impact loading. Part 2: parametric investigation of factors affecting behaviour at high loading rates

In Part 1 of this two-part set of articles, it was established that the effect of high-rate uniaxial compressive loading on the behaviour of plain-concrete specimens can be accurately predicted by a finite-element (FE) model able to carry out reliable three-dimensional (3D) static and dynamic non-linear analyses. By employing a material model based on the static properties of concrete, it emerged that it is the inertia of the specimen’s mass which is primarily responsible for any changes in the concrete specimen behavior due to the rate of loading. However, the existing experimental data are characterized by considerable scatter. Furthermore, when reviewing the details of the various experimental investigations carried out to date, it is apparent that a number of parameters (such as the static uniaxial compressive strength of concrete fc, the experimental techniques used for the tests, the shape and size of the specimens, the density and moisture content of concrete, etc.) vary from one experiment to another. The variation of these parameters, the absence of laws capable of accurately quantifying their effect on specimen behaviour, and the scatter that characterizes the experimental data add to the uncertainty and difficulty in interpreting such data, hampering a better phenomenological understanding and more confident predictions of the response of structural concrete at high rates of loading. Thus, it is the aim of this article (Part 2) to use the FE model in order to establish the individual and combined effects of these parameters on the response of plain-concrete prismatic specimens under high rates of uniaxial compressive loading and, in so doing, to identify the significance of their contribution to the overall scatter that characterizes experimental data.