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

For each design three different outer dimensions of specimens are considered as a result
of repeating the respective unit-cell with the different edge measures of 2, 3 and 4mm as
shown in figure 4a. As shown in figure 4b, a MTS machine is used for compressive
testing along x, y and z to evaluate the respective Young Modulus.
Superior plate
a) b)
Specimen Compression
load
Inferior plate
Fig. 4 - a) Three different sizes for each design; b) Compressive mechanical testing.
Each experimental testing is reproduced "in silico" running a FE linear analysis with
tetrahedral solid elements of 10 nodes and assuming PCL as an isotropic material (E =
290 MPa and ν = 0.3). As an example, figure 5 shows the FE model associated with the
microstructure design A. A finite displacement is applied at one end of the FE model
while the opposite end has displacement constrained in the load direction.
Fig. 5 - a) Finite element model of the prototypes manufactured and respective
simulation of the compressive testing.
4. RESULTS
Figure 6 shows the correlation of the data collected from the numerical models (e.g. see
figure 5) and experimental compressive testing (for all designs, sizes and directions).
The quality of the results is measured in terms of linear regressions and R-squared. Each
cluster of points in the graph has to do with a directional stiffness x, y or z (e.g. three
clusters are clearly seen for design B) whereas the range of Young Modulus E in each
cluster has to do with the different specimen sizes tested.