Study On The Impact Resistance Of The Composite Honeycomb Sandwich Structure Under Impact Of Different Impactors

Owing to the low density,high rigidity,stable structure,bending resistance,and good shear resistance,the honeycomb sandwich structure is widely used in the aviation,rail transport,automobile,and other industries.However,its low-speed and heavy-load impact resistance is poor and the impact sensitivity is high.The overall performance of the structure decreases significantly after impact,thus reducing its service life.The result is that the honeycomb sandwich structure has certain limitations in practical application.In this study,aiming at the carbon/glass fiber hybrid composite NOMEX honeycomb sandwich structure,its impact resistance performance under low speed and heavy load impact was explored.This study had important implications for this structure in practical applications.The main research contents were as follows:Through the study of theoretical and numerical simulation methods for the mechanical properties of the honeycomb core in out-of-plane compression,suitable constitutive relation of the honeycomb core was determined and the isotropic ideal elastic-plastic honeycomb core model was established.The accuracy of the simulation model was also verified by out-of-plane compression experiments.The out-of-plane compression deformation process and mechanical properties of the honeycomb core were investigated.By studying and improving the damage initiation criteria and damage evolution of composite materials,an accurate three-dimensional progressive failure model was established.The laminate was then subjected to low-velocity and heavy-load impact test with small diameter impactor.The impact damage performance of the laminate under small diameter impactor was initially investigated through different impact energies.The validity of the three-dimensional progressive failure simulation model of the laminate was verified by comparing the experiments with the simulations.The impact damage performance of the laminate under different diameters of conical impactor,hemispherical impactor and flat impactor was further investigated using the validated simulation model.Finally,the impact resistance of the laminate with different impactor was compared and analyzed.Based on the validated the honeycomb core compression simulation model and the laminate impact simulation model,an impact simulation model of the honeycomb sandwich structure was developed.The damage characteristics of honeycomb sandwich structure affected by the impactor energy,impactor shape,and impact diameter were investigated using tests and simulations.The change law of the energy absorption of the honeycomb sandwich structure was further revealed based on the impact force and impact energy.The bearing mechanisms of the honeycomb sandwich structures under impact of different impactor shapes and impactor diameter was explored.This study focused on the impact resistance of the honeycomb sandwich structure by experiments and simulations.The effects of impact energy,impactor shape and impactor diameter on the damage modes,failure characteristics,load carrying capacity and energy absorption of this structures were analyzed.This research can provide a reference for the reasonable evaluation of the bearing capacity under the impact by different impactors and the lightweight design of this structure.