Abstract: When designing the structure of a certain solid propellant rocket motor’s thrust vector control system, the designer must make sure if it bears the extreme working loads, the nozzle should not have the large axial displacement, and there must be the certain contact strength between the concave-convex sphere and rolling element, meanwhile do not produce excess plastic deformation. It is an elastic-plastic frictional contact problem of a complex structure which can not calculate and measure under complex loads. To solve the key problem of the contact load-bearing property which decides the design of the system structure and functions into play, the pendulous test of the system is simulated and the elastic-plastic frictional contact model between all the components concerning the surface intensify layer is established. The nozzle’s displacement, stress, deformation distribution and the destruct principle of joint material between the concave sphere-convex sphere and rolling element are calculated and analyzed. The problem of elastic-plastic coupling’s finite element calculation is solved by high-precision 3D friction contact method with Lagrange multipliers. By contrast with the pendulous test results, system contact load-bearing performance, finite element method and its result’s rationality are examined, and provide a more efficient and precise calculation method for designing this type of thrust vector control system.

Key words: Contact load-bearing property, Elasto-plastic friction contact finite element method, Pendulous test, Solid propellant rocket motor, Thrust vector control system