Numerical simulation of the dynamics of a reinforced concrete slab under an air shock wave

Abstract

Deformation and fracture of a reinforced concrete slab under the effect of an air shock wave are considered. The research involves data from the public experiment "Blind Blast Test". The slab is loaded by an air shock wave resulting from high explosive detonation in a shock tube. The results of calculations and experiments are compared quantitatively and qualitatively. Quantitative comparison is made for the history of movement of the reinforced concrete slab key points during the process of deformation. Qualitative comparison is made for photographs of the destruction of a real reinforced concrete slab and distribution of the damage fields obtained by calculation. The numerical simulation is carried out in the LS-DYNA code, and the finite element method with an explicit time integration scheme is used. The CSCM (Continuous Surface Cap Model) model is used to model the concrete material. This model is an isotropic constitutive model with three-variant surface of ductility; the strength characteristics of the material depend on the rate of loading, and its damage is considered separately for compressive and tensile loads, which allows taking into account the partial recovery of compressive strength. The mathematical description of the model is given as part of the paper. Steel reinforcement of the concrete slab is modeled explicitly with beam finite elements. Finite element meshes of the concrete volume and reinforcing elements are coupled by means of the kinematic automatically calculated equations. The properties of the reinforcement are set within the classical theory of elastic-plastic strengthening material flow with the criterion of limiting states in the form of Huber-Mizes and taking into account visco-plastic effects. The influence of boundary conditions, practical mesh convergence, and capability of the mathematical model to predict the location of zones of material failure, displacement, and deformation of the structure are studied.