A new idea for occupant and belt system by wave propagation analysis 2000-05-0187
If the reality of the impact phenomena in the field of collision
becomes well understood, that will open the path for the research
of safety and security in a considerable manner. Therefore, the
dynamic behaviors of the occupant and the belt system should be
sought through very careful analysis. In this work, we use the
computer simulation technique by dynamics of multibody systems and
FEM continuum model. The relation between the occupant''s
motion and all the potential correlating phenomena in the belt
system is to be cleared. And eventually, the simulation will lead
to advanced seat belt systems.
A response for the impact would be divided into two phases:
impulsive response immediately after collision and the subsequent
quasi-static response. The former is essentially conceived to
compose of stress wave, and the latter is elastoplastic response.
The response for the impact, therefore, will be observed as
follows: the generation and propagation of stress waves within the
webbing and the acceleration response within the occupant. The
former response should be integrated as belt force F, and the
latter as head G''s, etc.
In order to prove that phenomena, model of occupants''
seat belt system in frontal collision is to be examined. For
observing of the propagation phenomena of the stress wave, FE belt
model has been introduced. The behaviors of the stress wave are
characterized in the forms of the propagation of Von Mieses stress.
From the time evolution, it can be seen to increase like a
stepwise- wave, which is a result of superposition of the
reflection on the traveling wave. Eventually, the responses
immediately after collision have been proved to compose of the
A key point for controlling the impulsive response immediately
after collision would be found in the process of artificially
building analogous phenomena to the propagation and reflection of
the waves. We are taking a positive approach in order to improve
the two factors: the restraint capacity for occupant and the
efficiency of belt system. More specifically: Improvement in
occupant protection techniques (Decrease of peak Gs); and Reduction
of the impulsive load on the seat belt systems (Decrease of peak