Biomedical Engineering – From Theory to Applications

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Biomedical Engineering – From Theory to Applications
Phalanx: The virtual model of the phalanx has been tested to:
1. compression with a force evenly distributed on the superior surface of the phalanx
head, while the bone is fixed at the basis (Fig 11 a- The stress diagram; Fig 11 b- The
displacements diagram);
2. bending given by a force which acts at the middle of the bone, both extremities
(proximal and distal) being fixed (Fig 11 c- The stress diagram; Fig 11 d- The
displacements diagram);
a. b. c. d.
Fig. 11. The results obtained by numerical simulations for the above considered loading
cases for the phalanx bone
Radius: In Fig. 12.a. we present the mesh structure of the virtual model of the radius bone.
In Fig.12.b, a longitudinal section through radius is presented. The virtual model was tested
with a moment of 4.8 Nm (torsion) applied on the surface of the radius head. The bone is
fixed at the inferior side. The virtual stress is given by a set of forces placed at the
extremities of the radius head in a plane normal to the longitudinal axis of the bone. The
stress diagrams are shown in Fig.12.c, while the deformations diagrams in Fig.12.d.
a. b. c. d.
Fig. 12. The virtual model of the radius (a), longitudinal section through radius (b) the stress
map (c) and deformation map (d)
Analysis of stresses and deformations of the fracture areas is carried out with the Finite
Element Method which allows: accuracy of the complex bony structure geometry, variation
of designing parameters, and combination with other bone modelling algorithms leading to
various types of analyses. The software allows the determination of the stress and
displacements distribution in some particular cases which determine the breaking of the
ulna. The correspondence between the clinical observations, virtual simulations and the
results obtained from the experimental tests using the universal testing machine EDZ20
certify the accuracy and the fidelity of the spatial geometry, but also of the bone structure, of
the mechanical properties of the bone.