Annals of Biomedical Engineering

, Volume 42, Issue 3, pp 661–677

Predicting the Elastic Properties of Selective Laser Sintered PCL/β-TCP Bone Scaffold Materials Using Computational Modelling

Article

DOI: 10.1007/s10439-013-0913-4

Cite this article as:
Doyle, H., Lohfeld, S. & McHugh, P. Ann Biomed Eng (2014) 42: 661. doi:10.1007/s10439-013-0913-4

Abstract

This study assesses the ability of finite element (FE) models to capture the mechanical behaviour of sintered orthopaedic scaffold materials. Individual scaffold struts were fabricated from a 50:50 wt% poly-ε-caprolactone (PCL)/β-tricalcium phosphate (β-TCP) blend, using selective laser sintering. The tensile elastic modulus of single struts was determined experimentally. High resolution FE models of single struts were generated from micro-CT scans (28.8 μm resolution) and an effective strut elastic modulus was calculated from tensile loading simulations. Three material assignment methods were employed: (1) homogeneous PCL elastic constants, (2) composite PCL/β-TCP elastic constants based on rule of mixtures, and (3) heterogeneous distribution of micromechanically-determined elastic constants. In comparison with experimental results, the use of homogeneous PCL properties gave a good estimate of strut modulus; however it is not sufficiently representative of the real material as it neglects the β-TCP phase. The rule of mixtures method significantly overestimated strut modulus, while there was no significant difference between strut modulus evaluated using the micromechanically-determined elastic constants and experimentally evaluated strut modulus. These results indicate that the multi-scale approach of linking micromechanical modelling of the sintered scaffold material with macroscale modelling gives an accurate prediction of the mechanical behaviour of the sintered structure.

Keywords

Selective laser sintering Poly-ε-caprolactone β-Tricalcium phosphate Micromechanical modelling Bone tissue engineering Mechanical properties Finite element analysis 

Supplementary material

10439_2013_913_MOESM1_ESM.tif (26 kb)
Figure S1. Eeff plotted against average segment grey-value for segments in the first phase of model development. Supplementary material 1 (TIFF 25 kb)
10439_2013_913_MOESM2_ESM.tif (26 kb)
Figure S2. Poisson’s ratio νeff plotted against average segment grey-value for segments in the first phase of model development. Supplementary material 2 (TIFF 26 kb)
10439_2013_913_MOESM3_ESM.tif (135 kb)
Figure S3. Segment material composition and average segment grey-value for segments in the second phase of model development. Supplementary material 3 (TIFF 134 kb)

Copyright information

© Biomedical Engineering Society 2013

Authors and Affiliations

  1. 1.Biomechanics Research Centre (BMEC), Mechanical and Biomedical Engineering, College of Engineering and InformaticsNational University of Ireland GalwayGalwayIreland

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