Material Identification on Thin Shells Using the Virtual Fields Method, Demonstrated on the Human Eardrum

Area of Science:

• Solid mechanics
• Computational mechanics
• Biomaterials engineering

Background:

• Material parameter characterization from experimental data is challenging, particularly for biological structures.
• The virtual fields method (VFM) enables inverse determination of material properties but its application to complex shapes is underexplored.

Purpose of the Study:

• To extend the VFM framework for analyzing thin curved shells (shells).
• To apply the extended VFM to determine the Young's modulus and hysteretic damping of the human eardrum.
• To validate the method using simulated and experimental data.

Main Methods:

• The virtual fields method (VFM) was extended to thin curved shells using Kirchhoff plate theory.
• Shell behavior was modeled with linear variation through thickness, separating bending and membrane strains.
• The VFM was applied using only outer surface displacement data.

Main Results:

• The extended VFM accurately determined material properties (Young's modulus, hysteretic damping) of the human eardrum from outer surface data.
• Identified properties align with existing literature values.
• Both bending and membrane strains significantly contribute to the total strain in the human eardrum.

Conclusions:

• The VFM is effectively extended for characterizing material properties of thin curved shells.
• The method provides accurate material property estimation for the human eardrum using non-invasive surface measurements.
• Understanding the interplay of bending and membrane strains is crucial for accurate eardrum biomechanical analysis.