Mineralized type-I collagen fibrils are made up of mineral hydroxyapatite and type-I
collagen and are known to have good mechanical properties. Hydroxyapatite by itself
is stiffer and collagen is relatively weaker. The development of a multiscale
virtual internal bond model (VIB) used to model the material behavior
and failure of such biocomposites was described in an earlier paper by the
authors. An explicit finite element based framework using a two parameter
fracture-constitutive VIB model, with an extrinsic length scale, was used in this
study.
The model used in this study is a nano sized dahlite mineral crystal
commonly found in collagen fibrils. Two important computational implementation
characteristics are presented here; namely the effect of a material parameter used in
the VIB model and the effect of thickness of the material at the nanoscale
on the failure behavior. The effect of the thickness is studied in order to
demonstrate the extrinsic length scale capability of the VIB model at nano length
scales.
Keywords
finite element analysis, collagen, biomineralization,
nanomechanical behavior, dentin, parametric studies
