Characteristic Verification and Parameter Optimization of Airbags Cushion System for Airborne Vehicle

摘要

The major methods to investigate the airbags cushion system are experimental method,thermodynamic method and finite element method(FEM).Airbags cushion systems are very complicated and very difficult to be investigated thoroughly by such methods.For experimental method,it is nearly impossible to completely analyze and optimize the cushion characteristics of airbags of airborne vehicle because of charge issue,safety concern and time constraint.Thermodynamic method fails to take the non-linear effects of large airbag deformation and varied contact conditions into consideration.For finite element method,the FE model is usually complicated and the calculation takes tens of hours of CPU time.As a result,the optimization of the design based on a nonlinear model is very difficult by traditional iterative approach method.In this paper,a model based on FEM and control volume method is proposed to simulate landing cushion process of airborne vehicle with airbags cushion system in order to analyze and optimize the parameters in airbags cushion system.At first,the performance of airbags cushion system model is verified experimentally.In airdrop test,accelerometers are fixed in 4 test points distributed over engine mount,top,bottom and side armor plate of hull to obtain acceleration curves with time.The simulation results are obtained under the same conditions of the airdrop test and the simulation results agree very well with the experimental results,which indicate the established model is valid for further optimization.To optimize the parameters of airbags,equivalent response model based on Latin Hypercube DOE and radial basis function is employed instead of the complex finite element model.Then the optimal results based on equivalent response model are obtained using simulated annealing algorithm.After optimization,the maximal acceleration of airborne vehicle landing reduces 19.83%,while the energy absorption by airbags increases7.85%.The performance of the airbags cushion system thus is largely improved through optimization,which indicates the proposed method has the capability of solving the parameter optimization problem of airbags cushion system for airborne vehicle.