Four-Point Bending Test on a High Reinforced Concrete Beam: Nonlinear Numerical Analysis Using Material Parameter Identification

Abstract

The numerical analysis of concrete or reinforced concrete structures using nonlinear mechanics tools is currently the focus of interest of many scientific institutions. Today, numerical modelling of the real behaviour of concrete and concrete reinforcement is mainly performed with the aid of nonlinear constitutive relations (nonlinear material models). Current modern computational systems based on the implicit or explicit finite element method include a relatively large amount of nonlinear material models intended for modelling the real behaviour of concrete and concrete reinforcement. However, the accuracy of the simulated behaviour of real concrete and reinforced concrete structures depends on the correct definition of the input parameter values of these material models. This makes the nonlinear numerical analysis process quite difficult because the correct definition of the input parameter values of (in particular) the material models for the modelling of concrete is often not a trivial task. However, a combination of nonlinear numerical analysis with the identification of the input parameter values of the used material models based on relevant experimental data can be currently employed to address this task. The aim of this paper is to perform a nonlinear numerical analysis of a high reinforced concrete beam stressed by four-point bending so that the numerical response of the beam corresponds to the real response of the beam as closely as possible. For this purpose, an optimisation-based parameter identification process is used in this paper. Within this process, the input parameter values of a nonlinear material model of concrete which is known as the modified CSCM model and implemented in LS-DYNA finite element software are identified (optimised). Specifically, the parameter identification is based on the combination of optimisation methods with nonlinear numerical simulations and experimental data. The optimised input parameter values of the material model are an important result of the performed parameter identification process because they make it possible to achieve the primary aim. It can be concluded that the applied procedures and obtained results can be advantageously used in further analyses of concrete or reinforced concrete structures.