Numerical Study On Dynamic Mechanical Properties Of Aluminum Foam Sandwich Panels

As a new type of composite material,aluminum foam has many excellent properties,but its own rigidity is low,which is not convenient to use directly.On this basis,the researchers developed the aluminum foam sandwich structure.In the past two decades,aluminum foam and its sandwich structure have been rapidly developed and widely used.In daily use,aluminum foam sandwich panels must be subjected to some dynamic loadings such as impacts?explosions,etc.Therefore,the study of their impact resistance is an extremely important task.In this paper,based on the finite element method and the relevant theoretical knowledge in collision process,the dynamic mechanical properties of curved sandwich panels with aluminum foam were numerically simulated by using ANSYS/LS-DYNA computer program.The specific work and results are as follows:The dynamic performances of curved sandwich panels with single-layer aluminum foam under impact of steel balls were simulated.The dynamic response process of curved sandwich panels and the influence of different loading conditions on its performance were analyzed in detail.In the aluminum foam sandwich structure,the panel plays a major role in resisting bending,shearing stress and improving the overall stiffness,and the aluminum foam core is the most important energy dissipation component.The displacement of the back plate and the energy consumption of the curved sandwich structure increase with the increase of loading impulse;when the projectile impacts at a vertical angle,the deflection of the back plate is much larger than that of other incident angles,which causes the most serious damage to the structure.The influence of the structural parameters such as the material of the plate and the curvature of sandwich panels on the damping and energy absorbing properties of aluminum foam curved sandwich panels is discussed.The results show that the use of the stiffer steel as the plate of the sandwich panel leads to a decrease in the energy absorption efficiency of the aluminum foam core,but it is beneficial to reduce the deformation of the sandwich panel;the curved sandwich panel with aluminum alloy panel has higher energy absorption and cushioning capacity.The deflection of the back plate of the curved panel structure is obviously smaller than that of the flat panel,and the total energy dissipated is also more.It shows that reducing the radius of curvature can effectively reduce the maximum kinetic energy of the sandwich shell after being impacted,and strengthen the ability of the sandwich panel to bear impact loadings.The finite element model of the curved sandwich panel with double-layer aluminum foam was created and its mechanical properties under the impact of the aluminum foam projectile were simulated.It had been found that the curved sandwich panel with double-layer aluminum foam is less deformed than the single-layer curved sandwich panel of the same thickness,and the overall impact resistance is more excellent.The anti-collision characteristics of double shell structures with different thickness of the panel were compared and analyzed.It was concluded that the thin front and middle plates are favorable for the aluminum foam core to fully exert the buffer energy absorption characteristics.At the same time,increasing the thickness of the upper and lower aluminum foam core layers can significantly reduce the deflection of the back plate,but with the thickness of the core layer increases,the energy absorbed by the curved sandwich panel is slightly reduced.