Biomedical Engineering Reference
In-Depth Information
Fig. 10.6
Accuracy comparison between the developed model and available FEM models. Com-
putation of deformation by applying loads on a simple object (
a
), 2 objects (
b
) and a generic hip
joint (
c
)
To simulate the mechanical behavior of deformable objects, our simulation
model [
37
,
39
] is based on a fast 1st-order Finite Element system implementa-
tion, which offers a good trade-off between accuracy and computation speed. This
model based on a particle-system representation allows for the accurate represen-
tation of anisotropic nonlinear viscoelastic deformation models and is particularly
well suited for modeling the behavior of highly deformable materials. Thanks to
its lumped mass approximation, such models can be integrated with high-efficiency
numerical integration methods typically used in particle systems, as well as with
efficient integration of collision effects and geometrical constraints. Moreover, an
efficient numerical integration technique is used to provide good performance in the
computation of these mechanical models, both in the context of dynamic animation
and quasi-static relaxation. Concretely speaking, the different techniques considered
to build an efficient simulation model are [
32
,
60
,
61
]:
•
A fast 1st-order Finite Element implementation system for non linear behavior.
•
3D specific improvements of the co-rotational element transformation which is
appropriate to simulate anisotropic and isotropic materials and allow accurate
computation of the large deformations.
•
Pseudo-Dynamic Stop-and-Go relaxation for fast convergence for large displace-
ments.
•
Modeling elasticity strain-stress relationships with polynomial formulations for
simple and efficient modeling of the non-linear material behavior.
•
Efficient collision processing techniques based on incremental computation
method.
The developed simulation model is implemented in a framework offering an ade-
quate compromise between efficiency and versatility. The accuracy of themechanical
model has been validated through simulation comparisons with publicly available
