Research On The Design Of Functional Gradient Structure Of Vehicle Bottom Protectio

The design of protective components at the bottom of a protective vehicle is one of the key points in the research to improve the anti-explosive performance of vehicles.Especially as asymmetric combat has become the main method of modern war conflicts,vehicles are facing threats such as improvised explosive devices and landmines.How to improve vehicle protection ability to reduce the damage of occupants in the car is a problem that needs to be solved urgently.Therefore,it is of great significance to carry out research on the design of the underbody protection component of the vehicle.This paper takes a certain type of military vehicle as the research object,based on the explosion shock wave theory and the nonlinear finite element theory,using a combination of finite element simulation and experimental research to study the dynamic response of the vehicle body structure and the damage of the occupants in the vehicle under the explosion environment.At the same time,the energy absorption mechanism and energy dissipation of the functionally graded aluminum foam structure are studied,and the functionally graded aluminum foam structure is applied to the protective components,and the structural design and optimization of the protective components are carried out to reduce occupant damage in a targeted manner.This article mainly carried out the following research work:(1)Explain the explosion shock wave theory and the propagation characteristics of the explosion shock wave in different media,and explain the theoretical basis of the simulation explosion shock wave algorithm.Based on the steel plate explosion bench test,the accuracy and calculation efficiency of three common explosion simulations are compared and analyzed,which lays a theoretical foundation for the selection of subsequent research algorithms.(2)Based on the Deshpande-Fleck model,the foam aluminum sandwich panel structure is established.On this basis,the influence of different gradient parameters on the anti-explosive performance of the sandwich panel and the energy dissipation of different parts of the functionally graded structure are studied.And with the relative density of the layered foam aluminum core layer as the design variable,the functional gradient design of the foam aluminum sandwich panel is carried out.The research results have certain reference value for applying the functionally graded structure to the anti-explosive protection of the bottom of the vehicle.(3)A finite element model of a military vehicle was established based on the idea of modular modeling,and the accuracy of the model was verified through a car body bench test.The dynamic response of the vehicle body under the explosive environment at the bottom of the vehicle and the transmission path of the explosive impact force are analyzed.At the same time,the occupant’s motion posture in the vehicle and the occupant safety evaluation index are studied.(4)A parameter analysis of the structure and material of the vehicle protection component panel and back plate is carried out,and a design scheme with better structure and material is obtained.On this basis,the sandwich part is designed with functional gradients,and the significance of the aluminum foam core layers at different positions is analyzed.Through experimental design,the establishment of Kriging proxy models and the use of NSGA-Ⅱ multiobjective optimization algorithms to optimize the protective components,the final result is the two design schemes based on the occupant protection capability and the lightweight protection components have a certain performance improvement compared with the original scheme.