Damage Research On Composite Honeycomb Sandwich Structure Subjected To Bird Impact

As a kind of "structural material",composite honeycomb sandwich structure is widely used in radome,cowling,wing,tail and other aircraft components.For the composite honeycomb sandwich structure subjected to bird impact,the gelatin bird was used as the impactor for impact experiment;the finite element model was established and verified.The dynamic response and damage characteristics of composite honeycomb sandwich structure during bird impact were analyzed.Firstly,the numerical modeling method of gelatin bird was studied.The experiment of aluminium plate subjected to bird impact by using gelatin bird instead of real bird.Two damage modes of the gelatin bird appeared.One was the fluid-like failure,the other was the remaining part rebound after the front end breaks.In numerical modeling,the SPH method discretization and the equation of state constitutive were used for the gelatin bird of first damage model;the Lagrange method discretization and elastic-plastic with damage constitutive were used for the gelatin bird of second damage model.Then,the constitutive parameters were inverted respectively.The numerical result is in good agreement with the experimental results;it showed that the modeling method is reasonable.In order to study the damage form of the composite honeycomb sandwich panels under the gelatin bird impact and the effect of impact speed,honeycomb height and bird shape on dynamic response of the structure,the experiment of the composite honeycomb sandwich panels subjected to gelatin bird impact was conducted.The typical damage morphology of the composite honeycomb sandwich structure was described,some parameters on the damage degree was analyzed.The sandwich structurel appeared the global bending deformation and local deformation during the impact.Based on experimental results,the finite element model was established.The modeling method of laminated composite panel and honeycomb core was discussed.The validity of the model was proved by comparison with the experimental results.Based on the verified finite element model,the energy absorption characteristics and energy dissipation path of the sandwich structure during the impact were analyzed.The results show that most of the impact energy was converted into the internal energy of bird;others were converted into the internal energy of the structure.It was also found that the change of the layer way of the panel fiber has a significant effect on the impact resistance and energy absorption of the structure.Finally,the finite element model of the composite wing leading edge was established,the damage characteristics of the leading edge structure and the dissipation path of impact energy was analyzed,the effects of impact locations on structural damage characteristics were studied.