Bending-Induced Progressive Damage of 3D-Printed Sandwich-Structured Composites by Non-Destructive Testing

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• 3D-printed composites are increasingly used, necessitating research into their structural integrity under load.
• Understanding progressive damage is crucial for reliable application of these materials.

Purpose of the Study:

• To investigate the damage mechanisms of 3D-printed sandwich composites under three-point bending.
• To correlate mechanical performance with damage progression using multi-modal monitoring.

Main Methods:

• Utilized acoustic emission (AE) monitoring to detect damage events.
• Employed digital image correlation (DIC) for full-field strain and deformation analysis.
• Applied micro-computed tomography (Micro-CT) for high-resolution structural visualization.
• Integrated AE, DIC, and Micro-CT for comprehensive damage assessment.

Main Results:

• Increasing carbon fiber content from 10% to 20% in face sheets boosted average bending strength by 56%.
• AE analysis, aided by k-means clustering, differentiated damage modes: matrix cracking (<50 kHz), debonding/delamination (50-150 kHz), and fiber breakage (>150 kHz).
• DIC revealed significant deformation patterns during damage evolution, complementing AE and Micro-CT findings.

Conclusions:

• The combined AE-DIC-Micro-CT approach effectively characterizes damage initiation and propagation in 3D-printed composites.
• Fiber content significantly impacts the mechanical properties and failure mechanisms.
• This integrated methodology aids in improving the design and reliability of 3D-printed structural composites.