Study On Crashworthiness Of Aluminium Honeycomb Sandwich Fixed Table Of Train Based On Occupant Protection

The casualties caused by train collisions are shocking.One of the reasons is that the lack of passive safety restraint system in the train leads to the fierce secondary collision between passengers and the interior of the vehicle under the action of inertia.A design of honeycomb surface sandwich structure energy absorbing table that can be crushed as a whole is proposed.The main research of this thesis is as follows:（1）The integral collapsible honeycomb and skin sandwich structure energy absorption table was designed,and the finite element model of honeycomb sandwich structure energy absorption table was established,which was assembled with the seat and dummy finite element model into the sliding impact simulation scene.（2）The vertical and longitudinal bearing capacity of the energy absorbing table under different design and structural parameters was analyzed by simulation.The analysis results showed that the permanent vertical and longitudinal plastic deformation of the energy absorbing table with 9 grooves in the specified structural parameter range decreased with the increase of the structural parameters,and the deformation was lower than the standard requirement of 2.54mm,so the energy absorbing table had a certain vertical and longitudinal bearing capacity.The posture response and injury comparison results of the dummy in the seat-dummy–honeycomb sandwich fixed table/traditional fixed table slide impact simulation verify that the energy absorbing table can effectively crush to absorb the kinetic energy and greatly protect all parts of the 50th percentile Hybrid III dummy from fatal injury.However,under the initial structural parameters,the impact force level of the designed fixed table is still high due to premature compaction.It is necessary to further study the impact of structural parameters on the impact protection performance of the fixed table.Analysis of the influencing factors of impact protection performance of sandwich ficed table with different structural parameters showed that the sandwich fixed table with 9 grooves on the honeycomb surface has batter impact protection effect on the 50th and the 5th percentile dummies.The increase of structural parameters increases the holistic stiffness of honeycomb sandwich structure,but has different impact protection effects on 50th and 5th dummy.For 50th dummy,the impact protection effect of honeycomb sandwich structure was positive and then negative,while for5th dummy,the impact protection effect of honeycomb sandwich structure continued to be negative.（3）According to the different results of the influence of structural parameters on the combined thoracic index（CTI）of different specifications dummies,a multi-objective optimization model for structural parameters of energy-absorbing table was established.The parameters of honeycomb cell wall thickness,skin thickness and table thickness were taken as design variables,and the CTI of different specifications of dummies were taken as target responses.The orthogonal experimental design method was adopted to obtain the sample space of finite element simulation,and the Kriging response surface model was constructed with the simulation results of the samples.NSGA-II genetic algorithm was selected to conduct multi-objective optimization on the protection performance of energy absorption table,and pareto optimal solution set of index CTI＿5 and CTI＿50 was obtained.Finally,according to the principle of"minimum distance",the equilibrium optimal solution point C was obtained,CTI＿50 was 0.505,CTI＿5 was 0.603,and the corresponding design variable cell wall thickness t₁ was 0.10mm.The skin thickness t₂ is 0.185mm,and the desktop thickness T is 90.5mm.