On the strain rate limits in dynamic testing of concrete-like heterogeneous materials

Institute for Infrastructure and Environment, School of Engineering, University of Edinburgh, William Ranking Building, The King’s Buildings, Edinburgh EH9 3JL, UK

Abstract

The bulk dynamic behaviour of concrete in generally known to be strain rate dependent. However, explanation of the underlying mechanisms has been a subject of debate in the research community. Among other factors, the extent of validity of existing experimental data for concrete-like materials in the high strain rate regime is believed to have further complicated the situation. This paper is concerned about the strain rate limits for dynamic testing of concrete specimens in association with the size requirement for representation of the composite material. The strain rate limits as may be established by elastic theories are discussed firstly. Representative simulation results from numerical experiments using a mesoscale model are then described, and non-uniform distributions of stress and damage under excessively high strain rates are highlighted, and this leads to discussion on the correlation between the externally measured data and the real responses within the sample material. Both dynamic compression and dynamic splitting tension are considered.