Simulation and Experimental Evaluation of Mechanical Properties of Thin-walled Porous Carbon-carbon Composite Grid Electrode

Carbon-carbon composite grids possess advantages such as low density, excellent thermal stability, and a reduced ion sputtering rate. These characteristics make them an effective solution for enhancing the long-range performance, longevity, and high specific impulse of future high-power ion electric propulsion systems. The grid is typically a vulnerable component in ion thrusters, the thin-walled porous carbon-carbon composite grid mounted ion thruster will experience significant impact and vibration during the orbital stage, which poses the risk of broken ribs and damage to the grid structure, seriously affecting the reliability and service life of the ion thruster. To rationally design the carbon-carbon composite gate and understand the stiffness variation law of the composite grid, in response to the development requirements for the composite grid of a 10 cm diameter ion thruster, a mechanical characteristic analysis of a 10 cm diameter carbon grid was carried out based on the ABAQUS finite element simulation platform. The 13.6g Grms random vibration and shock response spectrum were investigated, and analyzed with the pole components through simulation. Z-direction impact tests were conducted for verification.Research shows that carbon-carbon grid components meet the technical requirements of a first-order resonance frequency greater than 100 Hz and have no destructive stress phenomena. Carbon-carbon screen grid has a higher impact safety factor than molybdenum screen grid, with a safety margin of 2.53 times that of molybdenum screen grid under 1000g acceleration impact. The characteristic resistance value of the impact test is good. Adjusting the initial grid spacing of the screen grid to 0.70 mm can increase the thrust of the equal caliber distance thruster by 10.52%.The design of the grid installation ear damping device can further improve the dynamic stability of the screen grid.