Nonlinear structural dynamics of the inflatable re-entry vehicle experiment (IRVE)

As an emerging space technology, IRVE system has become a hot spot in reentry field due to its large payload ratio, small launch volume and flexible operation. The structural characteristics of IRVE system in severe flight environment need to be studied for the purpose of shape preserving and structural safety design. In order to improve the existing analysis method of IRVE system to be a complete system, a structural dynamic model considering aerodynamic pressure and heat transfer is developed in this paper. A structural dynamic model of IRVE system is established based on the nonlinear finite element theory, and the influences of different inflation pressures and film thickness on the static and modal characteristics are investigated. The distributions of surface pressure and temperature are obtained by CFD calculation to measure the real aerodynamic load in flight. Meanwhile, the unidirectional couplings of fluid-solid and thermal-solid are innovatively used to study the effects of aerodynamic and aeroheating on static and modal characteristics. The results show that the maximum static stress and the first order natural frequency rise with the increase of the inflation pressure, and decrease with the increase of the thickness of the film. The static characteristic is most affected by aerodynamic pressure when flight height is below 40km while most affected by aeroheating when flight height is above 40km. The first order frequency is greatly influenced by thermal expansion while less affected by aerodynamic pressure in flight. The investigations in this paper also provide methods to analyze the nonlinear structural dynamic characteristics of IRVE system considering hypersonic aerodynamic and aeroheating.