Damage mechanics - based creep - fatigue analysis of combustion chamber for satellite's bipropellant thruster

Abstract

Creep - fatigue analyses based on the concept of continuum damage mechanics were conducted for the combustion chamber used in a satellite's bipropellant thruster. The previously identified models and material parameters for the niobium alloy (C103) which is used as the combustion chamber's material were extended to deal with the prediction of the creep - fatigue behavior and the chamber life of a bipropellant thruster. The thrust force of 22 N thruster was selected for FEM analyses and post damage calculations. The analyses in different injection modes of continuation and pulse were conducted to evaluate their influence on the chamber's life. The maximum temperatures on a chamber surface were also changed for two patterns of 1250 °C and 1500 °C. The combustion chamber life was evaluated for the different surface temperature. The analysis results show that the calculated chamber's life of continuous injection at 1500 °C was shorter than that at 1250 °C because of plasticity damage. The analysis results also show that the major damage mode was creep and fatigue damage was very little in pulse injection. From the results, it is expected that the used models and determined material parameters can predict the mechanical features and creep - fatigue life for the combustion chamber of a bipropellant thruster.

Keywords

• damage mechanics
• bipropellant thruster
• niobium alloy
• high temperature
• creep
• fatigue