Evaluation of a Multiscale Modelling Methodology to Predict the Mechanical Properties of PCL/β-TCP Sintered Scaffold Materials.

A multiscale modelling methodology to predict the macroscale stiffness of selective laser sintered polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) materials is evaluated. The relationship between a micromechanics-evaluated composite material elastic modulus (E eff) and segment grey-value (GVave) is established for a 90/10 wt% PCL/β-TCP material and compared to the previously established E eff vs. GVave relationship for a 50/50 wt% PCL/β-TCP material. The increase in E eff with GVave was found to be greater for the 90/10 wt% material than for the 50/50 wt% material. Differences in the material microstructures are visible with greater local conglomerations of β-TCP in the 90/10 wt% material compared to the 50/50 wt% material. These results indicate that the relationship between E eff and GVave is material-specific and that one definition cannot be used to describe both materials. We have used the E eff and GVave relationship specific to the 90/10 wt% material to assign element-specific elastic properties in a high resolution macroscale strut finite element model to successfully predict the experimentally-evaluated strut effective stiffness of the 90/10 wt%. These results combined indicate that this multiscale modelling methodology reasonably predicts the effective elastic modulus of selective laser sintering struts with different material configurations, and that it can be used to determine the material-specific definition of the relationship between E eff and GVave for a particular material.