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To establish the efficacy of creep age forming of the integrally friction stir welded panels, feasibility experiments were first conducted on friction stir welded rib-web panels of 2A12 aluminum alloys by using a designed air-loading age forming setup, and then related forming characteristics were investigated by using a mechanical-loading setup on the samples with and without friction stir welding joints. Results show that good age-formability can be observed from friction stir welded rib-web parts after creep age forming. The surface springback of the integral parts decreases with increasing the aging time and temperature. For 2A12 aluminum alloy, under an aging temperature of 190°C, a relatively better forming effect and strength can be reached at an aging time of about 8h. Compared with the non-welded structures, the introduction of friction stir welding will inhibit forming rate and will shorten the time of creep age forming.

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.