Sensitivity Analysis and Optimization as Tools for the Inverse Concrete Material Model Parameter Identification

The application of complex nonlinear material models of concrete within the numerical simulations is currently the most used way for the purposes of modeling the nonlinear computer response of concrete structures. However, the modeling of nonlinear concrete behavior through the nonlinear material models very often brings with it the major problem. This problem can be specified as a user nescience of a large number of material model parameters which is very common. Nowadays, the solution of this problem is possible with the so called inverse analysis or identification which can be performed via the different methods and approaches. One of the most effective approach for the purposes of the inverse analysis is currently using the combination of sensitivity analysis with optimization algorithms. This mentioned approach is demonstrated within this paper in which the parameters of the material model called the Continuous Surface Cap Model are identified. Material parameter identification is performed on the basis of interaction between nonlinear numerical simulations, statistical and optimization methods and experimental data which are represented by a load-extension curve obtained from the unconfined uniaxial tensile (UUT) test. The final comparison of the experimental data with the numerically-simulated data for optimal parameter values is, of course, also part of this paper.