Modeling fatigue damage evolution in CMDB propellant based on dynamic modulus

Area of Science:

• Materials Science
• Mechanical Engineering
• Aerospace Engineering

Background:

• Composite modified double-base propellant (CMDB) is critical for solid rocket propulsion.
• Understanding its fatigue behavior under cyclic loading is essential for safety and performance.
• Temperature significantly influences material properties and degradation.

Purpose of the Study:

• To systematically investigate the fatigue behavior of CMDB propellant under strain-controlled cyclic loading.
• To quantify fatigue life evolution and mechanical response at various temperatures and strain amplitudes.
• To analyze the impact of pre-fatigue conditioning on propellant damage.

Main Methods:

• Strain-controlled cyclic loading tests were performed across a range of temperatures.
• Fatigue life and mechanical response were quantified.
• Pre-fatigue tests were conducted to analyze damage evolution.
• A three-stage fatigue damage evolution model was developed based on damage mechanics and viscoelasticity theory.

Main Results:

• Fatigue life of CMDB propellant increases with rising temperature.
• The stress response exhibits a distinct three-stage evolution: initial softening, stable development, and acceleration.
• The established three-stage model shows good agreement with experimental data.

Conclusions:

• The developed fatigue damage model effectively describes CMDB propellant behavior during cyclic loading.
• This framework provides a mechanistic basis for assessing performance and predicting service life in solid rocket propulsion.
• Temperature is a key factor influencing the fatigue life and damage mechanisms of CMDB propellant.