A new method for determining the ogden parameters of soft materials using indentation experiments.

Area of Science:

• Biomechanics
• Materials Science
• Dermatology

Background:

• Understanding skin's material properties is vital for tribo-mechanical analysis.
• Hyperelastic models, like Ogden's, describe skin's mechanical behavior but obtaining in-vivo parameters is challenging.
• Existing models struggle with thin, nonlinear skin tissues under large deformations during indentation tests.

Purpose of the Study:

• To propose a pragmatic method for obtaining Ogden parameters for in-vivo skin tissue.
• To combine experimental indentation data with numerical simulations for accurate parameter extraction.
• To address the challenges of material and geometric nonlinearity in thin skin specimens.

Main Methods:

• Experimental indentation tests to acquire force-indentation depth data.
• Numerical simulations to determine strain fields and apply Hayes' contact model.
• Linearizing material behavior in small increments and using Hooke's law to derive stress-strain relationships for Ogden parameter calculation.

Main Results:

• A novel method successfully combined experimental and numerical approaches.
• Obtained Ogden parameters for in-vivo skin tissue.
• Validated the method by comparing experimental and simulated force-indentation curves.

Conclusions:

• The proposed method provides a viable approach for determining in-vivo skin Ogden parameters.
• This technique accurately accounts for material and geometric nonlinearities in thin skin.
• The findings contribute to a better understanding of skin's mechanical behavior for various applications.