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Development and Validation of a Mathematical Breakable Leg Model
Technical Paper
1993-13-0012
Published September 08, 1993 by International Research Council on Biokinetics of Impact in Switzerland
Sector:
Language:
English
Abstract
In a previous study on impact response of the human knee joint
in lateral car-pedestrian collisions a mathematical model of
pedestrian lower extremity with a human-like knee joint was
presented. The results showed that the model lacked adequate
representation of the deformation and fracture of the leg segments
since the response was shown to be strongly dependent on whether
the leg was fractured or not. In this study, a mathematical model
which would also represent a breakable leg was developed and
implemented into the pedestrian lower extremity model.
The leg model consists of two rigid-body elements connected by a
"fracturable joint". The moment-deformation
characteristics of the "fracturable joint" are described
by the user subroutines, which were prepared and added to the
MADYMO 3D program system. The input data for the "fracturable
joint" model originate from available biological specimen
tests.
Computer simulations of car-pedestrian impact with this modified
pedestrian model were conducted at a speed of 31 km/h in four
different configurations, and compared with previously performed
human leg specimen tests. Different types of bumper compliance and
bumper levels were simulated. The bumper force, the accelerations,
the condyle contact forces and the ligament strains were calculated
during simulations. The results showed that the modified model gave
a higher biofidelity than did the previous model with the
undeformable representation of the leg segments. The calculated
parameters such as bumper forces and accelerations corresponded
with the measured parameters in tests. The impact response of the
lower extremity could be well predicted by the model.