Puncturing of soft tissues: experimental and fracture mechanics-based study

Area of Science:

• Materials Science
• Mechanical Engineering
• Fracture Mechanics

Background:

• Soft materials are susceptible to failure from local rupture due to sharp objects.
• Understanding puncturing mechanics is crucial for material performance and safety.

Purpose of the Study:

• To investigate the mechanics of puncturing in soft materials using a sharp-tipped needle.
• To develop an analytical model describing puncturing as a mode-I crack propagation.
• To establish a relationship between puncturing force and material properties.

Main Methods:

• Analytical modeling of puncturing as a 2D mode-I crack propagation.
• Small strain elasticity analysis for closed-form toughness parameters.
• Nonlinear finite element analysis using an Ogden hyperelastic material model.
• Experimental validation using puncturing tests on silicone materials.

Main Results:

• Puncturing force is determined by stored strain energy and crack propagation energy.
• Force depends on fracture toughness, material stiffness, and penetrator sharpness.
• Theoretical predictions align with experimental results on silicones.

Conclusions:

• The study provides a theoretical framework for understanding soft material puncturing.
• A simple, reliable method for assessing puncturing safety in soft materials is proposed.
• Findings are applicable to material design and performance evaluation.