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

Abstract

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.

The effect of 3D printing on the morphological and mechanical properties of polycaprolactone filament and scaffold

“…FEM is a versatile and powerful simulation tool to demonstrate the mechanical behavior of systems, which has utilized in the 3D printing field especially in the improvement of the scaffold designs with tissue‐specific morphological and mechanical properties . This method can be combined well with good repeatability and high control that the 3D printing technique has on the fabricated geometry . Microextrusion‐based FEM models of the scaffold can be made accurately using Computer‐Aided Design (CAD) approach.…”

Evaluating the effect of increasing ceramic content on the mechanical properties, material microstructure and degradation of selective laser sintered polycaprolactone/β-tricalcium phosphate materials

“…Tensile testing of undegraded PCL struts was also carried out. Additionally, previously reported tensile data for undegraded 90/10wt% [29] and 50/50wt% [35]struts are reported, including stressstrain and elastic modulus (E) data.…”

“…Summary of degradation study mechanical testing data for PCL (grey), 90/10wt% (blue) and 50/50wt% struts (red). The change in elastic modulus for each material is shown in A, the change in tensile strength is shown in B and the change in strain at the tensile strength is shown in C. Elastic modulus data for undegraded 90/10wt% PCL/β-TCP struts and 50/50wt% struts have been published elsewhere (in [35] and [29] respectively) and are included here for comparison purposes. PCL test sample sizes were n = 4, 3 and 5, for tests at weeks 1, 4 and 7, respectively.…”

Computational modelling of ovine critical-sized tibial defects with implanted scaffolds and prediction of the safety of fixator removal

“…In order to account for this, the elastic modulus of the undegraded PCL/β-TCP scaffolds was approximated based on the grey-value, using the method and data that were presented in previous studies [29,30], giving a value of 250.37…”