Nonlinear finite element algorithm for solving fully coupled thermomechanical problems under strong aerothermodynamic environment

The dynamic nonlinear thermomechanical coupling finite element (NTMCFE) algorithm is constructed for the nonlinear thermomechanical coupling analysis of the spacecraft structure under strong aerodynamic thermal and force loads with materials and boundary nonlinearity. The Newton–Raphson method is chosen for solving the discrete nonlinear thermomechanical coupling equations. The accuracy of the present algorithm in solving coupled nonlinear thermomechanical problems is verified by 1D and 2D examples. The simulation of the strong aerothermodynamic environment is achieved by solving the temperature, heat flux and pressure distribution of the external flow field through the gas-kinetic unified algorithm (GKUA), which is applied as a boundary condition for the thermomechanical coupling calculation of the corresponding structure by the fluid–solid boundary interpolation format. Two typical spacecraft component structures including solar sail-like plate and reentry capsule structures are used as research subjects. Then, the thermomechanical coupling analysis of the re-entry plate with material nonlinearity has been studied in depth. The results reveal that the displacement and stress inside the plate are more sensitive to material nonlinearity than temperature. Furthermore, the effect of surface radiation emissivity on the thermomechanical response of the reentry capsule structure is discussed. The presented algorithm offers a novel methodology for predicting the nonlinear thermomechanical coupling behavior of re-entry spacecraft.