Dynamic fracture of concrete in compression: 3D finite element analysis at meso- and macro-scale

摘要

Fracture of normal strength concrete cylinder under static and dynamic loading is studied numerically. 3D finite element simulations are carried out at macro- and meso-scale. At meso-scale the analysis is performed with and without accounting for the interface zone (IZ) between aggregate and mortar. Aggregate is assumed to be linear elastic, and mortar is modeled using rate-dependent microplane model. To better understand behavior of concrete under dynamic fracture in compression, a parametric study is carried out to investigate the influence of the volume fraction of the aggregate, the role of IZ, the influence of confinement at the loading surface, the role of concrete quality and the influence of the size of the test specimen. The comparison between meso-scale and macro-scale analysis shows that the macroscopic analysis is principally able to account for the major effects related to dynamic fracture of concrete. Dynamic resistance of concrete in compression (apparent strength) depends on a number of parameters, and it is mainly influenced by the inertia effects that are closely related to the load-induced damage. Finally, it is pointed out that dynamic increase factor for compressive strength (CDIF), such as currently defined in design codes, for relatively high loading rates does not represent the true material strength.