Effect of Microstructure on Micro-Mechanical Properties of Composite Solid Propellant.

Area of Science:

• Materials Science
• Computational Materials Science
• Solid Propellant Mechanics

Background:

• Understanding the relationship between microstructure and macro-mechanical behavior is crucial for composite solid propellant performance.
• Previous studies have not fully elucidated the specific contributions of various microstructural features and defects.

Purpose of the Study:

• To determine the effect of microstructure on the macro-mechanical behavior of composite solid propellants.
• To investigate the correlation between microstructural mechanical properties, initial interface defects, and macro-mechanics.

Main Methods:

• Generation of a composite solid propellant microstructure model using molecular dynamics (MD) algorithms.
• Analysis of the influence of grain filling volume fraction, particle size ratio, and initial defects on mechanical properties.

Main Results:

• Propellant mechanical properties are heavily reliant on mesoscopic structure.
• Higher grain filling volume fraction leads to a higher initial modulus.
• Particle size ratio affects tensile strength and breaking elongation; larger particles increase initial modulus but decrease tensile strength and elongation.
• Initial defects reduce uniaxial tensile modulus, tensile strength, and relaxation modulus, but do not alter relaxation behavior.

Conclusions:

• Mesoscopic structure is a dominant factor in composite solid propellant mechanical performance.
• Optimizing grain filling and particle size is essential for tailoring propellant properties.
• Initial defects significantly degrade mechanical integrity, highlighting the importance of defect control.