A Multi-Scale Submodel Method for Fatigue Analysis of Braided Composite Structures

Area of Science:

• Materials Science
• Mechanical Engineering
• Composite Materials

Background:

• Ceramic Matrix Composites (CMCs) are advanced materials requiring accurate fatigue life prediction.
• Existing methods may not fully capture the complex multi-scale damage mechanisms in CMCs.

Purpose of the Study:

• To develop and validate a novel multi-scale fatigue analysis method for braided CMCs.
• To investigate the fatigue behavior of 2D SiC/SiC materials and stiffened plates.

Main Methods:

• A multi-scale sub-model approach integrating finite element shape functions for displacement transfer.
• Coupling meso- and micro-scale models using a shear lag theory-based fatigue failure criterion.
• Analysis of 2D SiC/SiC fatigue life and stiffened plates under tension-tension loads.

Main Results:

• The developed method accurately predicts fatigue life, showing good agreement with experimental data.
• The analysis effectively incorporates meso-structural damage conditions into the fatigue assessment.
• The method demonstrates high computational efficiency and simplified macro-model requirements.

Conclusions:

• The proposed multi-scale fatigue analysis method is accurate and efficient for CMCs.
• This approach is well-suited for analyzing the fatigue of complex CMC structures, including stiffened plates.
• The study validates the accuracy of the meso-scale cell model and the shear lag theory-based fatigue criterion.