Investigation On Protective Mechanism Of UHMWPE/Aluminum Foam/Silicon Carbide Ceramic Composite Sandwich Panels Under Combined Blast Wave And Fragment Loadings

With the rapid advancement of weapon technology,various anti-ship weapons such as torpedoes,anti-ship missiles and precision guided bombs pose a serious threat to the vitality of ships.The navies of various countries are actively carrying out research on new protective structures,of which the use of new composite materials and new structural forms are the two main ideas.Metal aluminum foam is a kind of foam material with high porosity and high specific strength.It can show excellent performance of energy absorption and cushioning under blast and impact loads.However,its resistance to fragment penetration is relatively weak.In contrast,UHMWPE laminates and silicon carbide ceramic,which are traditional ballistic material,have excellent resistance to fragment penetration.When these 3 different material are combined in a certain way,the composite armors with better overall performance can be formed.It is of great significance to study the damage response of this new sandwich structure under combined blast wave and fragment loadings.The results can provide technical support for the application of this structure in ship protective system.The main work of this article is as follows:(1)Focusing on the solid plate and UHMWPE/ foam aluminum/ silicon carbide ceramic sandwich structure,an experimental study on the damage response under combined blast wave and fragment loadings was conducted,including a total of 9experimental cases.Subsequently,the failure modes of each component of the sandwich structure in the typical case were analyzed.And the effect of explosive equivalent,the thickness of the face sheets,the core material and the core sequence on the blast resistance of the sandwich structure was investigated.The results show that,for the sandwich panel with UHMWPE and aluminum foam core,when the thickness of the front face is equal to that of the back face,the blast resistance performance is the best.As for the core material,the structure with the aluminum foam and the UHMWPE core has the best resistance to damage.In addition,as for the core layer sequence,when compounded with a material with greater strength and hardness,the core layer with lower strength should be placed as the upper core.This will make the sandwich panel more resistant to damage caused by the combined loading.(2)The commercial code LS-DYNA was employed to simulate the damage response of the solid plate and sandwich structures under combined blast wave and fragment loadings.In addition,a typical case was selected to conduct a preliminary analysis from the perspective of the damage response process,the velocity/ acceleration response and the energy absorption characteristics.The results show that the numerical model can better predict the perforation of the face sheets,the collapse failure of the central area of the aluminum foam core layer,the fiber fracture and the delamination of the UHMWPE core layer.Moreover,the numerical prediction of the plastic deformation of the back face of the sandwich structures also has high accuracy.(3)Based on the simulation results,the difference in protective performance between solid plate and sandwich panels was compared and the effect of explosive equivalent,face sheet thickness,core material and core sequence on the structural damage response was analyzed.The results show that the sandwich structure’s resistance to the combined loading is generally stronger than that of solid plates of equal weight.An increase in explosive equivalent weight within a certain range will lead to an increase in the equivalent weight of the effective charge and a change in the shape of the effective charge.Thus,a larger destruction area and a more serious damage of the structure will occur.The thickness of face sheets achieves the effect on the sandwich structure’s resistance to damage by changing the balance between the attenuation capacity of the front face to the fragment velocity and the resistance ability of the back face to the impact.In addition,different core material combination and arrangement sequence have a greater impact on the structure’s resistance performance.This 2 factors mainly lead to the difference in the remaining speed when the high-speed fragments reach different core layers,and thus affect the structure’s energy absorption characteristics.Essentially,factors such as the thickness of face sheets,the core material and sequence all affect the structure’s resistance to combined blast wave and fragment loadings by changing the velocity/ acceleration response and energy absorption characteristics of the structure.The researches in the present study provide a useful reference for the evaluation and design of the resistance performance of UHMWPE/ foam aluminum/ silicon carbide ceramic sandwich structure against combined blast wave and fragment loadings.