关键词: 离子推力器；栅极组件；热应力；热形变

Abstract: In order to decrease the thermal deformation displacement of the 30cm diameter ion thruster’s grid components，material mechanics analysis method and finite element method were used to study distribution of thermal stress and thermal deformation displacement of grid components with and without edge constraint condition，related optimization measure and validation process are proposed. The obtained results indicate that，when the grids are equivalent to circular plates and the edge constraints do not exist，the maximum thermal deformation of the grid caused by tensile stress is about 0.3mm，and the maximum thermal stress is about 1.5MPa which occurs in the center of grids，while the deformation displacement in the normal direction is nearly zero. When the grid is equivalent to the circular plate and the edge constraint condition satisfies，the maximum deflection occurs at the geometric structural center，with its value being about 1.255mm，and the maximum tensile deformation in the oriental direction being 0.01 mm. The theoretical results are in rough agreement with the simulation results，and the real grid structure will cause larger thermal deformation displacement under this constraint condition，probably causing the grid’s bad focusing performance and short between the grids.The thermal design optimization validation indicates that decreasing the overall temperature distribution of the structure and using the material with small thermal expansion coefficient are good measures to reduce the thermal deformation.

Key words: Ion thruster；Grids assembly；Thermal stress；Thermal deformation