Theoretical Models and Numerical Methods for Adaptive Inflatable Structures

Abstract

The paper describes various approaches for mathematical modelling of adaptive inflatable structures (AIS) along with corresponding numerical methods. The introductory part presents a general idea of adaptive impact absorption (AIA) and the concept of inflatable structures equipped with controllable valves serving for internal pressure control. Application of AIS for adaptive absorption of the impact loading is briefly explained. The paper focuses on methods of modelling of inflatable structures, which are based on interaction between solid walls and fluid enclosed inside. Modelling of the solid walls is based on rigid body dynamics or initial boundary value problem of solid mechanics. In turn, modelling of the fluid utilizes either classical equilibrium thermodynamics or Navier-Stokes equations. Consequently, four possible combinations of the above approaches are distinguished, precisely analyzed and applied for modelling of different types of inflatable structures. Each model takes into account controllable valves, which require introducing additional coupling between parameters defining the valves and selected results of the analysis. Corresponding numerical methods include RungeKutta methods, finite volume method (FVM) applied for problems with mobile boundaries, classical finite element method (FEM) and finally FEM coupled with FVM. Proposed numerical methods and software tools are utilized for simulation of adaptive pneumatic cylinders, adaptive pneumatic fenders and membrane valves.