Research On The Influence Of Negative Poisson’s Ratio Honeycomb Structure On Front Crash Performance Of Automobile

The negative Poisson’s ratio structure has become the focus of current research at home and abroad due to its unique performance advantages in shear modulus,fracture toughness,impact strength,indentation resistance and energy absorption.Among them,the traditional concave-angle hexagonal negative Poisson’s ratio structure The structural form is simple,and the research and application are relatively extensive,but its structural form leads to a slight deficiency in energy absorption and impact resistance.This paper takes the traditional concave-angle hexagon structure as the research object,designs a new negative Poisson’s ratio structure and conducts research on the honeycomb structure on this basis,and finally applies it to the field of automobile frontal collision to study its performance under high-speed collision.Performance.The main research contents are as follows:Based on the traditional concave-angled hexagonal structure,six optimized primitive models were designed through the variable density topology optimization method.The arrangement of the honeycomb structure primitives was discussed and analyzed,and an appropriate arrangement was selected to establish each basis.Meta honeycomb structure: The difference between the optimized model and the traditional model is compared and analyzed from the aspects of energy absorption,specific energy absorption,collision force and structural equivalent Poisson’s ratio.The results show that the energy absorption and load-bearing impact resistance of the optimized model are higher than the traditional concave angle Hexagonal structure,and the optimized model 1 has a better energy absorption effect,its equivalent Poisson’s ratio is low,and the collision force is low,so it is selected as the main research structure in the later stage.The optimized structure is processed with 2×2 honeycomb structure to complete the static compression test of the structure;the corresponding simulation model is established according to the test conditions,and the structure deformation and load data in the test and the simulation are compared.The error between the initial elastic stage test and the simulated load data is less than 3%,the later load is slightly different but the deformation form is the same,and the structural deformation is basically the same,and it shows the inverted V-shaped negative Poisson’s ratio deformation characteristics.The optimization model was studied on the influence of primitive geometric parameters on the performance of honeycomb structure.Five geometric parameters of primitive arc included angle,connecting rod length,outer thickness,thickness ratio and aspect ratio are selected,and a suitable parameter change range is selected to study the influence of a single variable.The study finds that the cell arc included angle and connecting rod length have a positive effect.The honeycomb structure has a greater impact on the specific energy absorption,and the outer thickness and thickness ratio have a greater impact on the peak impact force and energy absorption of the structure,while the outer thickness under equal strain has basically no effect on the equivalent Poisson ratio of the structure.Energy absorption and equivalent Poisson’s ratio have a greater impact.In order to obtain the qualitative laws of various parameters and collision characteristics,the approximate equations of energy absorption,specific energy absorption,peak collision force and equivalent Poisson’s ratio with respect to geometric parameters were fitted using Minitab software based on a uniform experimental design.Based on the equation,the hyperstudy software was used to carry out a multi-objective optimization design with the goal of maximum energy absorption and minimum peak collision force.The final selected optimized size has nearly doubled the energy absorption compared with the original model size,which is higher than the energy absorption.57%,the overall collision force is lower.A small pure electric vehicle is used as a research platform to carry out the application research of negative Poisson’s ratio structure.The accuracy of the simulation model is verified by the comparison between the vehicle test and the simulation B-pillar acceleration.The optimized negative Poisson’s ratio structure is combined into a filling core and filled in the front end of the car for a 50 km/h frontal collision.The filling core is compared and analyzed.The difference between the front and back filling and the traditional reentrant hexagonal filling core after filling.The results show that after the optimized model is used,the acceleration of the B-pillar of the vehicle is reduced by 10.6%,and the amount of cab intrusion is reduced by 22% compared with the unfilled state,and is reduced by 11%compared with the traditional structure after filling.The collision force and the crushing distance are better coordinated.Contradictory,effectively improving the vehicle’s collision resistance.