Bioinspired toughening mechanism: lesson from dentin.

Area of Science:

• Materials Science
• Bioengineering
• Mechanical Engineering

Background:

• Dentin's microstructure features hard peritubular dentin surrounding soft intertubular dentin.
• This structure inspires the design of advanced composite materials.
• Understanding crack propagation in such materials is crucial for enhancing toughness.

Purpose of the Study:

• To investigate crack propagation in bioinspired materials with dentin-like microstructures.
• To analyze the role of fracture process zones in enhancing material toughness.
• To propose a design principle for developing high-fracture-toughness engineering materials.

Main Methods:

• Development of a micromechanical model under small-scale yielding conditions.
• Numerical simulations to observe crack propagation and fracture mechanisms.
• Comparison of dentin-like microstructures with homogeneous matrix composites.

Main Results:

• Observed a rising resistant curve (R-curve) behavior during crack propagation.
• Dentin-like microstructures in the fracture process zone enhanced fracture toughness.
• The bioinspired structure retarded void growth, promoting overall toughness.
• Fracture mechanism shifted from multiple void interaction to void-by-void growth.

Conclusions:

• A dentin-like microstructure in the fracture process zone significantly enhances fracture toughness.
• The combination of hard and soft materials around voids is key to damage tolerance.
• This bioinspired design principle offers a pathway for developing novel engineering materials with superior toughness.