Issue 51

M. S. Bennouna et alii, Frattura ed Integrità Strutturale, 51 (2020) 254-266; DOI: 10.3221/IGF-ESIS.51.20 261 Figure 13 : Evolution of the equivalent plastic strain for a path of the upper surface using different angles of grooves. Figure 14 : Evolution of the equivalent plastic strain for a trajectory in the median of the sample using different angles of grooves. Case of a path of the lower face Fig. 15 illustrates the evolution of the equivalent plastic strain along the lower path for different angles of the groove of the dies. It may be noted that the angle of 45 ° is the one which ensures the maximum of plastic strain on this surface of the sample with a maximum value equal to 1.8, while the low values are obtained with the angle of 60 °. It is visibly clear that the angle of 60 ° ensures higher plastic strain than the ones of 30 ° and 45 ° for the upper surface and the middle surface of the sample. For the lower surface, it is the angle of 45 ° which ensures a maximum value of equivalent plastic strain. It can also be seen from Fig. 16 that the value of the deformation increases progressively with the value of the angle with the exception of the lower surface. Influence of the depth of the groove To evaluate the influence of the groove depth on the process results, the value of the angle β was fixed to 45 ° by varying the value of the depth of the groove H. Three different values were used (3mm, 5mm and 8mm) as shown in Fig. 17.