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

GHz, 3 GB RAM). FE models required an average solution time of ~65 minutes (SUN
FIRE X2270 2 cpu / 8 core Intel Xeon X5550 @ 2.67GHz (16 cores with HT) 48GB of
RAM 1GB network interface).
DEA and FEA contact patterns corresponded well and predicted irregular, complex
contact for all three loading scenarios (Fig 4). For walking and descending stairs, both
methods predicted contact predominantly in the superolateral region, whereas for
ascending stairs, contact was predicted posteriorly (Fig. 4). DEA peak/average contact
stresses and contact areas were higher than FEA predictions (Fig. 5). Peak contact
stresses for DEA and FEA ranged from 9.8-13.6 and 6.2-9.8 MPa, respectively.
Average contact stresses for DEA and FEA ranged from 3.0-3.7 and 2.0-2.5 MPa,
respectively.
Contact Area (mm 2 )
1400
1200
1000
800
600
400
200
0
DEA
Posterior
FEA 0-7 MPa
Posterior
FEA 0-9 MPa
Posterior
W
Peak Pressure (MPa)
16
14
12
10
8
6
4
2
0
DS
Figure 4. Contact stresses corresponded well between DEA and FE for all loading scenarios.
The top/middle rows were scaled differently to show similarities in contact pattern (DEA contact
stresses were higher than FE). The bottom row shows the FE results scaled the same as the DEA
results (top row).
W DS AS
W DS AS
W DS AS
Figure 5. Contact areas corresponded well in all loading scenarios (left). DEA peak (middle) and
average (right) contact stresses were higher than FEA predictions for all loading scenarios.
Average Pressure (MPa)
8
6
4
2
0
AS
Anterior
Anterior
Anterior
9
MPa MPa
0
7
0
9
MPa
0
DEA
FEA