Numericalmodellingofthefracturebehaviourof limestone

Numerical simulations of the double-edge notched specimen subjected to tension are performed. The cohesive surface methodology is used for the simulation of the tensile tests. A plasticity law proposed by Carol et al. (Carol et al.1997) is introduced as constitutive law for the cohesive surfaces. The influence of the discretisation and of the material parameters defined in the model are studied. Finally, the numerical simula- tions are compared to the experimentally observed results. I INTRODUCTION In this paper, tensile tests on double-edge notched specimens are analysed experimentally and computa- tionally. The specimens are made of limestone called "Massangis". During experiments both the local, i.e. the crack path, as well as the global response, i.e. load-displacement curve, is recorded. These results are used as verification for numerical simulations 0 performed within the finite element context using the N cohesive surface methodology. A plasticity model 7' proposed by Carol et al. (Carol et al. 1997) is used as the constitutive law for the cohesive surfaces. Also the influence of model parameters and the finite ele- ment discretisation is studied. '" 50 2 EXPERIMENTAL SET-UP Figure 1. Geometry of the specimens and place of LVDT (All dimensions are in mm) Rectangular double-edge notched specimens are subjected to a tensile loading. The geometry of the specimens is given in Figure 1. The thick:i-1ess of the 3 EXPERIMENTAL RESULTS specimen is 11 mm. Two symmetric notches were made in the specimen in order to trigger the fracture Some typical load-displacement curves obtained process in the middle of the specimens. Two Linear during the experiments are given in Figure 2. After Variable Differential Transducers (L VDT) are used reaching the peak load, the load-displacement curve to measure the deformation.