New microscale constitutive model of human trabecular bone based on depth sensing indentation technique

Area of Science:

• Biomechanics
• Materials Science
• Biomedical Engineering

Background:

• Human trabecular bone exhibits complex mechanical properties at the microscale.
• Understanding these properties is crucial for diagnosing and treating bone diseases and designing implants.

Purpose of the Study:

• To develop a new constitutive model for human trabecular bone.
• To incorporate non-linear viscoelasticity into a microscale model based on indentation tests.

Main Methods:

• Formulated a microscale constitutive model using indentation tests on single trabeculae.
• Described elastic response with the hyperelastic Mooney-Rivlin model.
• Incorporated viscoelastic effects using a hereditary integral dependent on time and strain.

Main Results:

• Material constants were identified via stress relaxation and indentation tests with curve-fitting.
• The model was implemented in the Abaqus finite element package using a UMAT subroutine.
• Low curve-fitting error and good correlation between predicted and realistic trabecular bone viscoelastic behavior were achieved.

Conclusions:

• The proposed constitutive model effectively represents the non-linear viscoelasticity of human trabecular bone at the microscale.
• The model's accuracy, validated by low error and realistic predictions, supports its use in biomechanical simulations.
• This work provides a valuable tool for further research in bone mechanics and tissue engineering.