PSI - Issue 5

Abdelouahid El Amri et al. / Procedia Structural Integrity 5 (2017) 363–368 Abdelouahid El Amri / Structural Integrity Procedia 00 (2017) 000 – 000

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2. Materials and Methods In finite element modelling, the real material behavior is of utmost importance to facilitate the analysis. In order to accurately predict the metal flow and forming loads, it is necessary to have reliable input data. For many hot forming process problems, especially at elevated temperatures, which is the case in hot forming processes, the elastic deformation is often insignificant and therefore can be neglected, the flow stress is a function of strain and temperature and the flow stress is a function of strain, strain rate and temperature are used widely due to their simplicity and fast convergence in iteration. The materials used in this study were obtained from commercial sources. The 6060-T5 alloy was received as a hot, cross-rolled plate in the T5 temper and with length L= 50 mm and the depth D=15mm and the width 5 mm. In the context of thermo mechanical model with internal variables, and to get a more complete understanding of the Mechanical and thermal effect of materials during testing, numerical simulations of the 6060-T5 aluminum alloy were performed, to evaluate thermal loads at different at different set as well as within the plate. The numerical analysis using explicit dynamic finite element based on the ABAQUS Software, in order to reproduce the surface thermal loads and to obtain the temperature evolution in the plate. Finite element modeling is performed by assuming 3D deformation. The main mechanical and thermal Properties of tested specimens are summarized in Table 1, but the plate geometries and meshing are shown in Fig.1 To obtain a thermal stress loading under homogeneous uniform temperature distribution, the 6060- T5 aluminum alloy was restrained against axial expansion by creating an interaction boundary condition at its outside edge. In order to determine thermal strain in the analysis we have need to the thermal expansion coefficientα [ 12 ].Poisson’s coefficient does not depend on temperature and takes the constant value υ=0.3. A displacement boundary condition was applied at the ou tside extremity of the tensile specimen. The displacement was smoothly ramped up in the first portion of the test and then held constant. Table 1: Mechanical and thermal properties of 6060-T5 Aluminium alloy

AL6060-T5 Material Tensile strength Yield strength Elongation Young’s modulus Cyclic Yield strength Strength Coefficient

Values

225 330 178 310 58

2450 0.35 534 -0.07 0.052 -0.292

Strain hardening exponent Fatigue Strength Coefficient Fatigue Strength exponent Fatigue ductility Coefficient Fatigue ductility exponent

Figure . 1 : coarse meshes of steel

3. Damage model Equations

y  depending on the effective plastic strain p

eff  and the effective

This model determines the yield stress