FLUID STRUCTURE INTERACTION SIMULATION BASED ON IB-LBFS AND NFE FOR LARGE DEFORMATION MEMBRANE

The nonlinear dynamic responses and complex flow patterns of flexible fabric aircraft (such as parachutes, airships, balloons, etc.) in aerospace engineering under non-conservative aerodynamic loads are significant issues that urgently require resolution in the domain of large deformation fluid-structure interaction (FSI). This paper, catering to the numerical simulation demands of large deformation membrane structure FSI, proposes a two-way fluid-structure interaction computational model by integrating the Immersed Boundary-Lattice Boltzmann Flux Solver (IB-LBFS) method and the Nonlinear Finite Elements (NFE) method for membrane structures. It is equipped with functions such as the identification of dynamic deformation boundaries of viscous flow, the dynamic reconstruction of fluid-structure loads and object surfaces, the solution of non-regular thin film structures with hyperelastic materials, and large-scale parallel computing. With the constant pressure inflated bag as the research object, the fluid-structure interaction effect between the airbag and the viscous fluid under the influence of free incoming flow is analyzed. The results indicate that the predicted data of this model conform to the distribution characteristics of the flow field and the development law of structural responses. The two-way strong fluid-structure interaction computational program developed in this paper can be further applied to the evaluation of fluid-structure interaction effects of inflatable aircraft such as aviation parachutes and airships, providing theoretical references for the structural design, strength verification, and flight reliability assessment of future flexible aircraft.