Study On Mechanical And Acoustic Performance Of Novel Honeycomb Composite Sandwich Panels

Composite sandwich structure as a new type of bearing structure has been widely used in various projects.However,with our deeper understanding of the world,the structure must not only meet the load-bearing requirements but also have variety performance in different working environments.Porous honeycomb structures not only have outstanding mechanical properties,but also have sound-absorption and energy-absorption characteristics.Among them,chiral honeycomb structures with negative Poisson’s ratio have attracted wide attention from scholars at home and abroad in terms of mechanical load-bearing and multi-functional design and application.The composite sandwich structure with honeycomb cores and magnesium alloy face sheets is characterized by light weight and multi-function performance such as good mechanical and acoustic properties.In this paper,mechanical and acoustic properties of anti chiral honeycombs and honeycomb core sandwich structures are investigated.After typical core configurations are determined,the cohesive model for the skin-core adhesively bonded interface is verified,and the low-velocity impact simulation for the final composite sandwich panel is carried out.The effects of dimensionless parameters on equivalent mechanical parameters of anti chiral honeycombs are firstly investigated,and the accuracy of the results has been verified by comparing the consistency of theoretical calculation,finite element simulation and experimental results.On this basis,comparisons of compression simulations are performed for several honeycomb structures such as chiral honeycomb,traditional hexagonal and concave hexagonal honeycomb structures,and it is found that the anti chiral honeycomb has better energy absorption characteristics.The relationship between modal frequency and sound insulation characteristics curve is then analyzed by comparing the modal frequency and sound insulation of various honeycomb structures based on simulation method.Meanwhile,the mode I and mode II interface fracture toughness parameters are obtained through DCB and ENF tests.Based on the mechanical property parameters and VUMAT subroutine of the adhesively bonded layer,the numerical simulation for dynamic impact response of honeycomb composite sandwich panels with different configurations is finally carried out.The results show that:(1)the higher the ratio of the chiral honeycomb ligament length to the cylinder radius is,the smaller the equivalent elastic modulus is;the higher the Poisson’s ratio is,the higher the corresponding modal frequency is;and the higher the stiffness is,the higher the acoustic insulation is.(2)compared with traditional hexagonal and concave hexagonal honeycomb structures,the antichiral honeycomb structure has better mechanical properties,energy absorption characteristics,and sound insulation effect in the middle and low frequency range.(3)the interface fracture toughness parameters of sandwich panels obtained from experiments are accurate when used in the exponential cohesion model,and the obtained velocity-time history curve is in good agreement with the experiment result under dynamic impact loading.(4)the four-ligament antichiral honeycomb structure exhibits better impact resistance and maintains better integrity after subjected to low velocity impact.