Characterization of concrete specimen fracture response: 2D numerical study

The reported investigations undertaken so far on concrete fracture involve limited tests on laboratory size concrete specimens and provide a basic understanding of the fracture phenomenon, but the precise quantification of fracture parameters is still elusive. Therefore purely an experimental approach is not preferably a practicable solution, rather it is important to invoke the systematic computational approach for evaluating the load-crack mouth opening displacement and load–load line displacement responses to characterize the concrete fracture phenomenon.While performing the numerical study of concrete components using finite element method, mesh sensitivity is an extremely important issue which is investigated in this paper, through detailed analysis of geometrically similar three point bend (TPB) beams having constant length to depth ratio. The finite element modeling of the TPB concrete beams performed by incorporating the fracture energy based softening model predicted the results that are found to be mesh insensitive.In the present finite element analysis, the performance of triangular elements is investigated and observed to be superior over the quadrilateral elements. This has been concluded based on the completeness of interpolation function and discretization technique, which is illustrated by simulating a number of benchmark problems of TPB concrete specimens.The efficient analytical procedures to predict the parameters required to characterize the concrete fracture phenomenon are explored. The simulation of TPB specimen yields the parameters, such as maximum load, vertical displacement at maximum load, load vs. load line displacement and load vs. crack mouth opening displacement responses which are required for epitomizing the concrete fracture behavior. The numerically observed response is found to be in excellent agreement in most of the cases with the reported literature.