Dynamic fracture of concrete in compression: 3D finite element analysis at meso- and macro-scale
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O R I G I NA L A RT I C L E
Serena Gambarelli · Joško Ožbolt
Dynamic fracture of concrete in compression: 3D finite element analysis at meso- and macro-scale
Received: 24 January 2020 / Accepted: 12 March 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract 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. Keywords Concrete · Dynamic fracture · Rate sensitivity · FE analysis · Microplane model · Meso-scale approach
1 Introduction Understanding dynamic fracture behavior of concrete at high strain rates is fundamental for the safety assessment and design of concrete structures subjected to dynamic loading (impact and blast). It is well known that the behavior of concrete structures is strongly influenced by the loading rate [1]. Compared to quasi-static loading, concrete under impact load acts in a different way. First, there is a strain rate influence on strength, stiffness and ductility, and, second, there is inertia activated which influences the resistance and failure mode of concrete. The results of dynamic experimental tests show that after reaching some critical strain rate concrete resistance progressively increases with the increase in strain rate. This type of the response is typical for many different problems, e.g., compression, direct tension, bending, pull-out of anchors, etc. [1,2]. Communicated by Andreas Öchsner. S. Gambarelli (B) Materials Testing Institute, University of Stuttgart, 70560 Stuttgart, Germany E-mail: [email protected] J. Ožbolt Institute of Construction Materials, University of Stuttgart, 70560 Stuttgart, Germany E-mail: [email protected]
S. Gambarelli, J. Ožbolt
The compressive strength of concrete under dynamic loading is usually tested using hydrauli
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