Nonlinear viscoelastic characterization of bovine trabecular bone

Area of Science:

• Biomaterials Science
• Mechanical Engineering
• Orthopedic Research

Background:

• Trabecular bone's time-independent elastic properties are well-studied.
• Its time-dependent, viscoelastic behavior is less understood.
• Characterizing this behavior is crucial for accurate mechanical modeling.

Purpose of the Study:

• Investigate the time-dependent mechanical behavior of bovine trabecular bone.
• Identify nonlinear constitutive viscoelastic material parameters.
• Apply Schapery's model to describe the observed viscoelastic response.

Main Methods:

• Performed uniaxial compressive creep and recovery experiments on bovine trabecular bone samples.
• Utilized multiple load creep-recovery (MLCR) tests.
• Developed a methodology to separate recoverable and irrecoverable strains.

Main Results:

• Significant creep response, comprising both recoverable and irrecoverable strains, observed even at low stress levels.
• Viscoelastic response varied nonlinearly with applied stress.
• Schapery's nonlinear viscoelastic model successfully described the bone's behavior.

Conclusions:

• Trabecular bone exhibits nonlinear viscoelasticity, with strains being both recoverable and irrecoverable.
• Nonlinear viscoelastic recovery compliance showed stress-dependent stiffening and softening.
• Estimated material parameters, as polynomial functions of stress, confirmed this stiffening-softening trend.