BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI

60 Marius Catană and Daniela Tarniţă
accurately predicts the response and movements of the articulation as it is
resembled by experimental methods. The software packages take anatomical
data from CT and MRI scans and create computer models of anatomical
structures. A user can modify the image by defining various tissue densities for
display (Radu, 2006).
Virtual modeling of human knee joint have been addressed in several
articles on (Bae et al., 2012), (Fening, 2005), (Bahraminasaba et al., 2011),
(Sandholm et al., 2011), (Kazemi et al., 2011), (Kubicek & Zdenek, 2009). In
his articles (Vidal-Lesso et al., 2011) have been considered the components
tibia, femur, cartilage, notwithstanding the menisci and ligaments, while in the
articles (Kubicek & Li, 2009), (Fenning, 2005), was performed complex
modeling, taking into account the ligaments and menisci; (Sandholm et al.,
2011) take in consideration muscles that were simulated as rigid links. In his
work (Harryson et al., 2007) were also taken into account fibula, patella, and
patellar tendon. These geometric patterns were created from images taken by
MRI and CT, dual fluoroscopic images, or using automatic creation programs
(Mimics) for the geometrical model (Bingham et al., 2008). Virtual models
were analyzed with FEM, after performing a finite element model with
tetrahedral type (Vidal et al., 2008), hexaedral, or using automatic meshing
methods. The articles have used an algorithm for meshing with hexahedrons and
bricks in order to analyze with a much better approximation for the tibiofemoral
contact area (Fening, 2005), (Kazemi, 2011), (Kubicek & Zdenek,
2009).
There have been various investigations that present different analyzes in
the human knee. Analyzes were performed the femur, tibia, meniscus, cartilage
and ligaments, (Bingham's it., 2008), (Kubicek & Zdenek, 2009).Very few data
are available for other material properties like transverse and shear moduli
(Weiss & Gardiner, 2001).
2. Method
Components taken into account for this analysis are: the femur, distal
head of the femur (thigh bone cartilage), the two menisci: lateral and medial,
tibia cartilage, tibia, peroneus and fibula (Fig. 1). These components were
placed in a global system XYZ. This is necessary for proper placement locations
of the tasks that apply degrees of freedom for the entire assemble. Nonlinear
structural analysis is static; non-linearity is evident by the appearance of
nonlinear contacts in the cartilage and meniscus.
Changes and proper positioning of the components was done using the
package ANSYS Workbench 14.0, CAE software allows rapid modelling of a
proper record and control of geometric problems arising in the contact zone.
Position requires a real placement of components, a proper distance between
them and correct geometric structure.