ANALYSIS OF STRENGTH OF BRITTLE MATERIALS UNDER DIFFERENT STRAIN RATES USING LDEM SIMULATIONS

This paper presents a study on the variation of strain rate influence with the scale effect in quasi-brittle materials. Works in the literature report an increase of dynamic resistance with strain rate. To study this relation, a numerical model that combines the Finite Element Method and the Lattice Discrete Element Method is employed. This mixed model was implemented on the commercial software Abaqus/Explicit. The samples are prepared with FEM at the extremity and LDEM for the central part, which has a reduction in the crosssection, so the rupture occurs in the middle. In the simulations, four model specimens with dimensional variations were subjected to direct tensile testing with different strain rates. The results showed that with the increase of applied strain rate, the resistances also increase and the body dimension influences this behavior. The variation of the tensile strength is found without modifications on the elemental constitutive relationship or material parameters. At last, a method that could lead to an independent relationship between the dynamic intensification and the stain rate of scale effect is also proposed.