On the Non-linear Elasto-Plastic Behavior of AA6061-T6: Experimental and Numerical Implementations

In this study, using an elasto-plastic constitutive model, the structural response of an Aluminium alloy AA6061-T6 bi-failure specimen is investigated. The mechanical specifications and material model are fully defined. It is intended to evaluate the force variation versus the displacement field during a tensile loading test. Digital Image Correlation (DIC) approach is used to acquire the experimental data. Afterwards, a 2D model is analysed through Finite Element (FE) formulation considering an isotropic elasto-plastic regime and the obtained results are compared to DIC outcome. A reasonable agreement between numerical and experimental results was found. Additionally, the problem is numerically solved using the Natural Neighbour Radial Point Interpolation Meshless method (NNRPIM) formulation assuming an elasto-plastic behaviour for the material. An elasto-plastic return-mapping routine is defined based on von-Mises yield criteria to evaluate the stress tensor in a pseudo-time stepping scheme, which imposes displacements. Taking into account the non-linear system of equations, a non-linear Newton-Raphson algorithm is used to obtain the converged solution. The NNRPIM results have a reasonable agreement compared to the DIC solution. The obtained results imply that the proposed elasto-plastic NNRPIM procedure is feasible and robust.