Depth-dependent strain fields of articular cartilage under rolling load by the optimized digital image correlation...

Area of Science:

• Biomechanics
• Biomaterials Science
• Orthopedics

Background:

• Articular cartilage experiences significant rolling loads during daily activities.
• Understanding depth-dependent mechanical behavior is crucial for joint health.
• Previous studies have not fully characterized these behaviors under rolling conditions.

Purpose of the Study:

• To investigate the depth-dependent mechanical responses of articular cartilage under rolling load.
• To analyze normal and shear strain variations across cartilage layers.
• To establish relationships between strain, rolling time, compressive strain, and rolling rate.

Main Methods:

• Utilized an optimized digital image correlation (DIC) technique for rolling experiments on articular cartilage.
• Quantified depth-dependent normal and shear strains within the cartilage.
• Varied parameters including rolling time, compressive strain, and rolling rate.

Main Results:

• Normal and shear strains initially increased then decreased with rolling time, correlating with compressive strain.
• Strain values decreased with cartilage depth under constant compression.
• Increasing rolling rates reduced normal strain and affected shear strain differently across layers.
• Normal strain increased with rolling cycles, showing a 30.6% rise from the 1st to 99th cycle.

Conclusions:

• Developed a fitting relationship for normal strain and normalized depth, validated by experimental data.
• The study provides critical insights into articular cartilage mechanics under rolling loads.
• Findings can inform the design of joint replacements and treatments for cartilage degeneration.