Study On Occupant Protection In Vehicle And Self-balancing Scooter Collision

In recent years,the electric self-balancing scooter（ESS）has become a new choice for short-distance travel because of its environmental friendliness,fast and convenient advantages.Due to the lack of regulatory constraints,the quality of ESS varies from good to bad,and traffic accidents often occur because of random lane changes and overtaking in the motor lane,so the drivers of ESS are seriously injured.Based on this background,the rigid-flexible coupling model of the collision between the vehicle and the electric self-balancing scooter with additional protective structure is constructed by combining the multi-body system dynamics and explicit finite element method,and the protection of the protective gear to the driver of the electric self-balancing scooter is improved through multi-objective optimization research.Firstly,the multi-body dynamic collision model of vehicle and electric self-balancing scooter is established,and the vertical hybrid III 50%male dummy model is selected to simulate the driver of electric balancing vehicle.By adjusting the initial position and angle of the dummy model,the pre-simulation method is used to match the electric self-balancing scooter.At the same time,three-dimensional modeling software UG is used to establish the solid model of the protective structure,and the finite element model of the protective structure is generated by the finite element pre-processing software Hypermesh,which is adjusted to the appropriate position and associated with the multi-body model.Finally,the rigid-flexible coupling model of multi-body dynamic collision of the automobile-electric balanced vehicle is generated.Secondly,based on the above-mentioned vehicle-electric self-balancing scooter collision model,under the same collision speed and angle simulation conditions,the impact of protective structure on the injury degree of the driver of the electric self-balancing scooter is compared.The protective effect of protective structure on the driver of the electric self-balancing scooter is verified by taking the synthetic acceleration of the driver’s head mass center as the evaluation index.Thirdly,considering that the actual collision accident is affected by many factors,based on the rigid-flexible coupling model of multi-body collision of ESS with additional protective structure,the dynamic responses of ESS and its drivers under different collision velocities,angles and positions are studied respectively,and the collision positions,the peak acceleration of the mass center of the head of ESS and its drivers under different conditions are compared.The occurrence time and other mechanisms,and according to the composite acceleration of the head mass center and the damage index HIC₁₅ of the electric self-balancing scooter driver,the injury degree of the driver was predicted.Finally,on the basis of the validated protective structure model,taking the longitudinal installation position of the protective plate as the design variable,and taking the synthetic acceleration of the driver’s head centroid and the synthetic acceleration of the thoracic cavity as the objective function,the protective structure is optimized by multi-objective design.Combining multi-body dynamics simulation technology with multi-objective optimization method,the simulation results of head centroid acceleration and peak thoracic acceleration of balanced vehicle drivers under different working conditions are solved,and the response surface model is established and its accuracy is verified.On this basis,parameter sensitivity analysis is carried out to study the effect of single variable and two variables on the objective function.Based on this,the mathematical model of the above multi-objective optimization problem is established,and the Pareto frontier of the optimal solution set is obtained by genetic algorithm.