Strain-Rate-Dependent Constitutive Equations for Concrete

TLDR

The study aims to quantify how strain rate affects concrete’s compressive and tensile strengths and to develop corresponding constitutive equations. Tests were conducted at quasi‑static rates (10⁻⁷–10⁻⁵ s⁻¹) on an MTS machine and at high rates (10⁻¹–10³ s⁻¹) on a split‑Hopkinson pressure bar, and the resulting data were statistically analyzed to derive strain‑rate‑dependent constitutive equations that were used to modify an existing nonlinear concrete model. The derived equations capture the strain‑rate dependence of concrete strength in both compression and tension, enabling more accurate modeling of dynamic behavior.

Abstract

This paper summarizes the results of a comprehensive experimental study to quantify the effects of strain rate on concrete compressive and tensile strengths. Direct compression and splitting tensile tests were conducted at quasi-static rates (between 10−7/s and 10−5/s) in a standard MTS machine to establish the “static” properties. These same tests were conducted at high strain rates (between 10−1/s and 103/s) on a split-Hopkinson pressure bar (SHPB) to determine the dynamic material properties. A statistical analysis was performed on the data and strain-rate-dependent constitutive equations, both for compression and tension, were developed. These constitutive equations were subsequently employed to modify an existing quasi-static, nonlinear concrete material model.