ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

ENUM (MPa)
100
90
80
70
60
50
40
30
20
10
0
Fig. 6 - Correlation of experimental and numerical Young Modulus (linear regressions).
5. DISCUSSION
As seen in figure 6, consistency between predicted and measured results for all sizes is
most clearly seen in design B (dashed line is ideal). On the contrary, design C with
smaller geometric details presents experimental Modulus (EEXP) more dependent on the
unit-cell size due to the feature size limitations of the SLS machine. The EEXP values
more closely match the numerical ones (ENUM) as the unit-cell size increases. Geometry
B is comparatively simpler and thicker and thus easier to manufacture, i.e., it fits better
the machine resolution that is around 500μ. Besides these size effects, all the
experimental values are below the numerical ones (on average this means -20% for
design A, -10% for B and -40% for C). This demand for further research work on "solid"
PCL characterization and modeling taking into account the directionality introduced by
the fabrication process, SLS.
6. REFERENCES
y = 1,181x + 10,084
R 2 = 0,8453
y = 1,7306x + 8,9596
R 2 = 0,6436
y = 1,0788x + 3,0799
R 2 = 0,9689
Design A
Design B
Design C
0 20 40 60 80 100
E EXP (MPa)
1. Hollister S.J. and Lin C.Y., Computational design of tissue engineering scaffolds.
Comput Methods Appl Mech Engrg, 2007, 196: 2991-2998.
2. Kang H., Lin C-Y and Hollister S.J., Topology optimization of three dimensional
tissue engineering scaffold architectures for prescribed bulk modulus and
diffusivity. Struct Multidisc Optim, 2010, 42: 633-644.
3. Coelho, P.G., Fernandes P.R., Rodrigues H.C., Cardoso J.B. and Guedes J.M.,
Numerical modeling of bone tissue adaptation-A hierarchical approach for bone
apparent density and trabecular structure. J of Biomechanics, 2009, 42: 830-837.
4. Coelho, P.G., Fernandes P.R., Rodrigues H.C., Multiscale modeling of bone tissue
with surface and permeability control. J of Biomechanics, 2011, 44: 321–329.