Research On Hail Impact Responses And Damage Predictions For Pyramidal Lattice Truss Structures

Composite materials have higher specific strength and stiffness,better antifatigue and corrosion resistance,designed performance,and low thermal expansion.The usage of composite materials in the aircraft structure is increasing.But its performance of impact damage instance is relatively poor,even though in the case of low energy impact,the mechanical properties of the structure will also be obviously reduced.In addition,existing technology can't avoid the hail impact damage during the life of the aircraft,which affects the safety of the flight.In the paper,the process of hail impact for pyramidal lattice truss structure is simulated by the finite element software ABAQUS.Smooth Particle Hydrodynamic and the software HyperMesh are used to deal with the model and set the conditions.Then make the parameter settings in ABAQUS,such as material properties,model assembly,boundary conditions and the contact form.Study the impact responses and predict the damage from the aspects of deformation of the target,instance impact force,and compression and tensile damage of fiber and matrix.And the simulations for different cases concerning to lay up conditions of the composite panels,initial impact velocity,and angles of impact velocity have been carried out.The results indicate that under the conditions of compression and tensile damage for fiber and matrix,matrix tensile damage is the main form of damage.Damage area of the panel directly impacted is larger than that of the bottom one,and the duration time for the existence of damage is longer.The distribution of damage is related to the angle of laying up.It is found that the appropriate continuous same layer angel of panels has smaller damage area,and better performance for shock resistance.The greater the vertical velocity component is,the lager of the deformation and the damage degree are.However the reaction force of the clamped boundary and the vertical velocity component are not positive correlation.Becuse when the impact velocity exceeds a certain value,the lattice structure has serious damage,while the integral rigidity of the target is decreased,the force instead decreasing.