Numerical Simulation Study On Three-point Bending Property Of Aluminum Foam Sandwich

Aluminum foam sandwich is a new type of composite material with low density,high specific strength,high specific stiffness,energy absorption and vibration reduction,heat insulation,sound insulation and many other excellent properties.It can be widely used in aerospace,machinery industry,automobile.The main purpose of this paper is to study the numerical simulation of aluminum foam sandwich to predict the three-point bending mechanical properties of sandwich panels.Therefore,the three-dimensional model of aluminum foam and sandwich panel is established in this paper,and the simulation of three-point bending performance is carried out,and the simulation results are compared with the experimental results to verify the accuracy and feasibility of the simulation.At the same time,the collision energy absorption capacity of the aluminum foam sandwich structure on the bumper of the car was studied.The main research contents are as follows:(1)In this paper,a quasi-static three-point bending test was carried out on a aluminum foam sandwich prepared by bonding 7050 aluminum alloy matrix foam aluminum and 304 stainless steel panel.,the failure mode of the sandwich panel was observed,and the influence of panel thickness and core porosity on the deformation behavior of the sandwich panel was analyzed.Tests have shown that the failure mode ofaluminum foam sandwich under three-point bending load is mainly surface depression and core layer shear.When the porosity of the core layer is constant,the loading capacity of the sandwich panel increases with the increase of the thickness of the panel;when the thickness of the panel is constant,the loading capacity of the sandwich panel increases as the porosity of the core layer decreases.(2)A cubic cavity model was used to establish a simulation model of aluminum foam sandwich structure with uniform holes,the three-point bending behavior of the structure is simulated by finite element software,the effect of cell size and panel thickness on the mechanical properties of aluminum foam sandwich panels was analyzed.The results show that the pore size of the aluminum foam has no effect on the elastic deformation of the aluminum foam sandwich,but as the pore size of the aluminum foam increases,the yield strength of the sandwich panel gradually decreases.The loading capacity of the sandwich panel also increases as the thickness of the panel increases.The force-displacement curve obtained by the model simulation has great error with the test and cannot be used to simulate the actual three-point bending mechanical behavior of aluminum foam.(3)A three-dimensional random spherical model was used to establish a simulation model of aluminum foam sandwich structure with random holes.The three-point bending behavior of the structure was simulated.The simulation results and experimental results were compared and analyzed.The results show that the force-displacement curves of the simulation and test have three deformation stages: elastic stage,yield stage and failure stage.The mean error of the simulated and experimental peak loads is 25.3%,and the mean error of the absorbed energy is 35.95%.It shows that the simulation has certain accuracy and feasibility and can be used to predict the three-point bending mechanical properties of the sandwich panel.(4)The application of aluminum foam sandwich structure on automobile bumper was studied by finite element simulation.The energy absorption capacity of bumper filled with polypropylene and bumper filled with aluminum foam was compared and analyzed.The results show that whether it is a bumper of a steel plate or a bumper of an aluminum plate,the energy absorption capacity of the filled aluminum foam is larger than that of the filled polypropylene,and the bumper of the aluminum plate is most obvious.