Issue 50

G. Khandouzi et alii, Frattura ed Integrità Strutturale, 50 (2019) 29-37; DOI: 10.3221/IGF-ESIS.50.04 34 Figure 6 : Displacement – time curve for four points on Fig. 6. Figure 7 : CSOD curve for SCB specimen in X-FEM model [19]. C OMPARISONS BETWEEN DAMAGE AND X-FEM METHOD he concrete damage plasticity (CDP) model herein has just been used to validate X-FEM simulation results . (Fig. 8) illustrates internal energy and kinetic energy for SCB specimen in the CDP model. These curves are used for verification of CDP numerical modeling. According to the CDP model, internal energy has to be 8-10 times of the kinetic energy. In (Fig. 8) internal energy fluctuates between 0 and 1.6 (Kj) and kinetic energy varies between 0-0.2 (Kj). According to these results, the internal energy is 8 times kinetic energy. As it can be seen in (Fig. 9-b), the area with red colour is considered as the crushed area in the CDP model. The same load of 30000 N used in the X-FEM model (Fig. 9-a). The green area is regarded as a crack propagation area under the same load in X-FEM code. Comparison of two figures show the same areas of crack propagation under the dynamic load. Dynamic loads of 3000 N and 30000 N have been exerted to the models as shown in (Fig. 10-a) and (Fig. 10-b), respectively. Under the dynamic load of 3000 N the specimen doesn’t fail completely (Fig. 10-a) while under the load of 30000 N the specimen completely failed (Fig. 10-b). Increasing in the load that needs for the propagation of a crack in intact specimen rather than the specimen with initial crack is due to the existence of initial flaw. T