Structural Optimization And Performance Study Of Basalt/Carbon Fiber Hybrid Composites For Vehicles

The lightweight of automobiles can reduce emissions and fuel consumption,which is becoming more and more important today when environmental pollution and energy shortages are gradually aggravating.As a typical lightweight material,carbon fiber has been widely used in the automotive industry,but its cost is high and its toughness is poor.As a natural fiber,basalt fiber has stronger toughness and lower price than carbon fiber.The basalt/carbon fiber hybrid composite material can be obtained by combining two kinds of fibers with the same matrix.The shortcomings of a single fiber can be improved by fiber hybridization,the cost can be reduced,and the application prospect is wider.In this paper,the basalt/carbon fiber interlayer hybrid composite material is studied,and the low-velocity impact performance of the basalt/carbon fiber hybrid composite material is analyzed by establishing a damage model.Optimize the low-velocity impact performance of hybrid fiber composites based on the performance requirements of vehicle body parts subjected to impact loads.Apply the optimized structure to the front anti-collision beam of the car,and analyze its crash performance.The specific research contents are as follows:Basalt and carbon fiber composite laminates were prepared,and the basic mechanical properties of the two composite materials were tested to provide parameters for the subsequent establishment of the hybrid fiber composite damage finite element model.A three-dimensional progressive damage subroutine based on material fracture toughness was developed to simulate the in-plane damage of interlaminar hybrid fiber composites,and cohesive elements were used to simulate interlayer damage of hybrid fiber composites.The damage finite element model of hybrid fiber composites under three-point bending and lowvelocity impact conditions was established.The accuracy of the damage model was verified by theoretical prediction and experiment methods respectively.The low-velocity impact damage finite element model was used to analyze the impact performance of hybrid fiber composite laminates,and the impact response was studied by changing the ply structure and ply angle.The results show that when the number of basalt layers in hybrid fiber composites accounts for 25%,placing basalt outside can improve the impact resistance of hybrid fiber laminates and generate higher peak forces than single composites.As the number of basalt layers increases,the enhancement effect of impact resistance disappears.When all carbon fibers in hybrid fiber composites are located on the outside,the energy absorption of hybrid fiber composites increases compared to that of single fiber composites.The impact displacement gradually increases with the increase in the number of basalt layers,and the impact displacement of carbon fiber outside is smaller.The change of ply angle also affects the impact performance of hybrid fiber composites.The addition of ±45° ply enhances the impact resistance and increases the peak force of hybrid fiber laminates,while reducing energy absorption and displacement.This effect is more obvious when it is located outside.The peak force decreases when the 90° ply is on the surface.Since composite materials are mainly used for body parts in automobiles,the displacement and impact force of body parts should be as small as possible when subjected to impact loads.Taking the minimum displacement and impact force as the goal,and using the ply material and ply angle of each layer of the hybrid fiber laminate as design variables,the NSGA2 algorithm with real number coding is used to optimize the structure of the hybrid fiber laminate.In order to improve the calculation efficiency of the algorithm,The particle update formula of the particle swarm optimization algorithm is introduced into the NSGA2 algorithm.Finally,the optimal solution is selected using the method of gray correlation analysis to obtain the optimal hybrid fiber laminate structure.Finally,based on the ply structure with the best impact performance,the basalt/carbon fiber hybrid composite front bumper beam assembly was modeled,and compared with the steel front anti-collision beam assembly under low-speed and high-speed collision conditions.The results showed that the crash performance of the hybrid composite bumper beam was better than that of the steel bumper beam,and the mass of the bumper beam was reduced by 38.5%,which achieved the goal of lightweight.