Issue 48

M. Laredj et alii, Frattura ed Integrità Strutturale, 48 (2019) 193-207; DOI: 10.3221/IGF-ESIS.48.21 196 A displacement in the Z direction is applied from the input face to the output face on the mandrel to simulate the expansion process. The Johnson-Cook is used for the numerical simulation in order to take into account the parameters of the dynamic hardening and the speed of plate deformation, The Johnson-Cook parameters of the three aluminum alloys are shown in Table (1). A(MPa) B(MPa) n c m T f (K) Ta(K) . p  AL AU 4G [20] 350 440 0.41 0.0083 1 911 293 1 AL 6005-T6 [21] 270 134 0.52 0.015 0.859 893 293 1 AL 6082-T6 [22] 428 327 1.008 0.00747 1.31 855 293 1 Table 1 : Johnson-Cook parameters. With: A, B and n: are constants that describe hardening m = hardening exponent T f : Melting temperature Ta: Ambient temperature . p  : is the reference strain rate Figure 2 : Finite element model boundary conditions: (b) plane xy; (c) plane yz.