Abstract: Based on thermodynamics theory and finite element method, a finite element model of equipment and its airbag cushion system is established and verified experimentally. 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 research. Because nonlinear model of airbags cushion system is very complicated, the calculation takes tens of hours of CPU time. As a result, the large-scale calculation is impossible. In order to overcome this problem, surrogate models are employed instead of the complex finite element model based on extended latin hypercube method and radial basis function. Initial velocity, initial heeling angle, initial pitch angle, lateral velocity and gradient are variables, while maximum acceleration, maximum heeling angle, maximum pitch angle and maximum airbag pressure are responses. Considering the influence of landing condition, Monte Carlo method and surrogate model are used to calculate landing success probability of airdropping equipment under multi-condition. The landing success probability calculated is 95.84%. Acceleration is the primary contributor to cushion performance, while pressure inside airbag is secondary contributor.

Key words: airbag cushion system, airdropping equipment, assessment, Monte Carlo method, surrogate model