General method developing for analysis of soft landing system with air dampers
Dynamics, strength of machines, instruments and equipment
Аuthors*, **, ***
Design center «Technodinamika», 29, Ibragimov str., Moscow, 105318, Russia
The principle structure component of any soft landing system with air dampers is shell with a gas inside it. Behavior of such shell component during the landing defines the safety of the landing object. Area landing relief, weather, soil elasticity etc. defines the conditions of landing. Thereby, the deformation of the landing system every damper could be unique. However, different approaches are developed by other engineers and scientists, and the most popular — numerical methods to develop in LS-DYNA.
The main idea is to develop a mathematical model to estimate the behavior of the dampers under loading and also take into consideration elasticity of soil and cargo. Herewith, an interaction between inside and outside gas with shell is included into consideration. The proposed mathematical model is developed using combination of finite element and finite volume methods. Besides, the developed model uses an Arbitrary Lagrangian Eulerian (ALE) approach.
Such mathematical model has to be verified. Therefore we solved different problems using this model and compared them with well-known analytical solutions.
The first problem is to define a behavior of a closed cylindrical shell container. The air fills the inside volume of the container and the outside one. The inside and outside pressures differ from each other. The shell is considered as elastic and is loaded by the other body with various initial velocities. Furthermore, all bodies are in the gravity field. We obtained results by means of the developed analytical approach and ALE approach. These results show a satisfactorily difference.
Then we considered the problem of air flux through the perforation in the air damper during the landing. It helps us to define the influence of the outside air volume on the flux from the damper in case of numerical approach.
We also used ALE approach to simulate the deformation of the two air dampers with perforations during the landing. The influence of the considered dampers on each other is presented.Hereby, verification of the developing mathematical model to analyze the soft landing system with air dampers shown good convergence with analytical solutions. Then we will try to solve more sophisticated problems and compare the results with appropriate experimental data.
Keywords:soft landing system, dropped cargo landing, air dampers
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