Dynamic Splitting Tension Research Articles

MESOSCALE MODELING OF CONCRETE UNDER DYNAMIC SPLIT TENSION

In this paper, a mesoscale model is adopted to simulate concrete behavior under dynamic split tension. The concrete material is assumed to comprise coarse aggregates, mortar matrix, and an interfacial transition zone (ITZ). In the mesh generation process, random coarse aggregate particles are generated from a certain aggregate size distribution and then placed into the mortar matrix with ITZ between the coarse aggregate edge and the mortar matrix. Different aggregate shapes, such as circular, oval, and polygons are modeled to analyze the gravel and crushed stone aggregates. Numerical simulation is used to model the dynamic damage responses of a typical cylinder concrete specimen and a cube specimen under split tension. Velocity boundary is added as the dynamic loading. Reasonable tensile stress–strain relationships are obtained at the macroscale level; and the detailed stress wave distribution and the crack pattern are obtained at the mesoscale level. These numerical results agree well with conventional experimental results. It also shows that cracks are affected by aggregate distribution.

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

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.