A predictive model for strain hardening and inertia effect of aluminum tubes filled with aluminum foam

Studies on strain hardening and inertia effect of foam-filled tube (FFT) remain limited. Therefore, this work has conducted mesoscopic finite element analyses on FFTs. The 7075-T651 aluminum alloy is chosen for tube ma-terial and the 1100-H14 aluminum is employed for the base material of closed-cell foam. The deformation mechanism of the interaction between tube and foam, and the inertia effect on compressive response of FFTs, are both revealed. Results show that due to the interaction, FFT has a higher compressive stress compared with the sum of empty tube and individual foam under the same mass. As more material is involved, the load-bearing capacity, strain hardening, and interaction stress of FFTs all increase with the relative density of infilled foam. A predictive model is established to predict the compressive stress and strain hardening of FFTs. The load -bearing capacity of tube, the plastic hardening of foam, and the interaction effect between tube and foam are all considered in this model. Moreover, due to the inertia effect, the stress at the impact end is significantly higher than that at the support end under high-velocity impact. The one-dimensional shock wave theory is added to the model, enabling the prediction under high-velocity impact.