Study On The Low Velocity Impact Response Of Metal Foam Composite Sandwich Structure

Metallic foam sandwich structure is being widely used in aviation,aerospace automotive and construction engineering fields due to its excellent properties,such as low density,sound absorption,noise reduction,good impact resistance,high energy absorption capacity,multifunction,etc.The composite sandwich structures are often subjected to low velocity impact in practical applications.It is very important to investigate the mechanical properties of composite sandwich structures under low velocity impact,which decide whether composite sandwich structures can be applied in engineering fields.In this paper,the theoretical analysis,numerical simulation and experimental study on the low velocity impact of glass fiber reinforced aluminum foam sandwich panel is carried out from five aspects: core thickness,impact energy,stacking sequence,impact speed and punch size.The specific research contents are as follows.Based on the continuum damage mechanics theory,the damage evolution model of fiber reinforced composite unidirectional plate is deduced.Then,according to the fact that the single fiber strength is in line with the characteristics of Weibull probability distribution,the α parameter in the theoretical model is determined.The model can also be extended to the prediction of damage evolution of fiber reinforced composite unidirectional plates under different loading conditions by simple stretching and compression experiments.Secondly,the low velocity impact properties of glass fiber reinforced aluminum foam sandwich panel are studied.The effects of different core thickness and impact energy on the failure mode,energy absorption capacity,energy absorption efficiency and maximum contact load of composite sandwich panels were studied by means of drop hammer impact test.Thirdly,the finite element analysis model is established,and the finite element model is proved to have mesh convergence.The validity of the finite element model is verified by comparing the contact force displacement response curve,the absorbed energy and the failure mode to the experiments.Finally,the finite element model is used to simulate the low velocity impact performance of sandwich panels with different impact velocity,different layers of the composite material and different punch sizes.