Modeling And Simulation Research On Impact Dynamic Characteristics Of Lightweight Lattice Structures

The lattice structure is a new structural with lightweight,high specific strength,high specific stiffness,and multifunctional potential,which is an ideal structural material for the integration of new generation structural materials.However,the mechanical properties of the lattice structure itself have not been fully grasped,especially the study of the dynamic properties is not comprehensive enough.In the actual service environment will face a variety of severe operating conditions,including the mechanical impact is inevitable,such as the spacecraft in orbit by the impact of space debris,impact loads will cause different degrees of damage to the lattice structure,including much internal damage not visible,so that its load-bearing capacity is reduced,thus threatening the overall safety of the structure.In this paper,the linear elastic assumption of single-layer composite structure is introduced,and the damage behavior of fiber reinforced composite panel is judged and the material stiffness is reduced by combining with the three-dimensional Hashin failure criterion.The mechanical behavior of the connection interface inside the lattice structure is characterized by using the Cohesive element.The Johnson-Cook model is used to simulate the failure behavior of the metal lattice sandwich,and the impact dynamic model of the lattice structure is constructed.The block process was used to prepare the lattice structure,and two special positions were selected as the impact points to carry out the drop hammer test.The rationality of the model was verified by comparing the test results with the numerical simulation results.Based on the impact dynamic model of lattice structure,the process of punch penetrating lattice structure at different angles is numerically simulated,and the damage of lattice structure at different impact angles is studied by control variable method.The study shows that the smaller the impact angle is,the less the energy consumption of lattice structure is,but the larger the failure area of panel is.Based on the numerical simulation,the effects of different interface conditions between the composite panels and the interface conditions between the panel and the lattice sandwich on the energy absorption characteristics of the lattice structure are studied.It is concluded that when the impact position is not supported,the influence of the interface condition in the panel on the energy absorption characteristics is more obvious,and the interlayer condition of the laminated plate can show the maximum strength of the whole laminated plate at the appropriate value.Under the same energy,the film interface condition is high,and the damage area of the lattice structure panel is large,and the influence of incomplete fracture of the middle lattice cell on the failure area of the lower panel is greater than that of complete fracture.