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Comput Methods Biomech Biomed Engin. 2016;19(5):465-73. doi: 10.1080/10255842.2015.1041022. Epub 2015 May 11.

The sensitivity of nonlinear computational models of trabecular bone to tissue level constitutive model.

Author information

1
a Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program , University of Notre Dame , 147 Multidisciplinary Research Building, Notre Dame , IN 46556 , USA.

Abstract

Microarchitectural finite element models have become a key tool in the analysis of trabecular bone. Robust, accurate, and validated constitutive models would enhance confidence in predictive applications of these models and in their usefulness as accurate assays of tissue properties. Human trabecular bone specimens from the femoral neck (n = 3), greater trochanter (n = 6), and lumbar vertebra (n = 1) of eight different donors were scanned by μ-CT and converted to voxel-based finite element models. Unconfined uniaxial compression and shear loading were simulated for each of three different constitutive models: a principal strain-based model, Drucker-Lode, and Drucker-Prager. The latter was applied with both infinitesimal and finite kinematics. Apparent yield strains exhibited minimal dependence on the constitutive model, differing by at most 16.1%, with the kinematic formulation being influential in compression loading. At the tissue level, the quantities and locations of yielded tissue were insensitive to the constitutive model, with the exception of the Drucker-Lode model, suggesting that correlation of microdamage with computational models does not improve the ability to discriminate between constitutive laws. Taken together, it is unlikely that a tissue constitutive model can be fully validated from apparent-level experiments alone, as the calculations are too insensitive to identify differences in the outcomes. Rather, any asymmetric criterion with a valid yield surface will likely be suitable for most trabecular bone models.

KEYWORDS:

constitutive model; finite element method; nonlinear; trabecular bone; yield

PMID:
25959510
PMCID:
PMC4641845
DOI:
10.1080/10255842.2015.1041022
[Indexed for MEDLINE]
Free PMC Article

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