Modelling and
Accident
Reconstruction
GESAC has extensive experience in developing finite element and
lumped mass models of biological systems and complicated
engineering systems.  FE and lumped mass models have been used
in support of design and load and stress analysis.  Some models that
we have developed, such as the FE model of an infant eye have been
used to evaluate the stresses on the infant eye when it is exposed to
an external input such as force or acceleration.  In addition, GESAC
has extensive experience in reconstruction of automotive accidents.  

1.  Finite Element Modelling

Most of the dynamic FE models that GESAC has developed have
been based on LS-Dyna.  Our staff maintain and enhance the SImon
FE model of the head and brain for the NHTSA.  We have developed
LS-Dyna models of Thor dummy components to guide our design
efforts.

GESAC has been evaluating the risk of Retinal Hemorrhage in infants
due to external inputs such as acceleration and force applied to the
head.  A preliminary model of the infant eye has been developed in
collaboration with Paediatric Ophthalmologists and Paediatricians at
the Sick Childrens Hospital in Toronto and Brown University Hasbro
Medical Centre.  
Please click on this line to view a PPT presentation
made at the Sick Childrens Hospital.  

2.  Lumped Mass Modelling

As a general rule, GESAC tends to develop lumped mass models to
support design efforts before developing FE models.  Lumped mass
models are developed using DYNAMAN, our copyrighted 3-D
occupant simulation model.  DYNAMAN can be used to model other
dynamic systems not involving automobiles and occupants.  A
description of the DYNAMAN software is available on the page entitled
"Software".  

3.  Accident Reconstruction

GESAC staff have reconstructed a number of accidents in support of
the NHTSA as a part of the CIREN and other programmes.  
Biodynamic reconstruction conducted as a part of the CIREN
programme involved reconstructing accidents in the Washington, DC,
Baltimore area if the occupants were taken to the University of
Maryland Trauma Centre.  Data about the vehicle and anthropometric
data about the occupant were obtained from site police reports.  These
data were used to reconstruct the accident and to evaluate points of
contacts between the human and the vehicle.  Medical reports from
the Trauma Centre were used to optimise the simulation runs so that
estimated points of contact and levels of injury estimated by the
simulation model were reasonably close to observed injuries and their
severity.  Please see the page titled "Software" for further information
on DYNAMAN©and DynPFDSim software.