|
Material
Modeling Effects on Impact Deformation of Ultralight Steel Auto Body
Authors:
Srdan Simunovic - Oak Ridge National Laboratory, Jody Shaw - U. S. Steel
Corporation, and Gustavo A. Aramayo - Oak Ridge National Laboratory
SAE
2000-01-2715
Steel Processing
Effects on Impact Deformation of Ultralight Steel Auto Body
Authors: Srdan
Simunovic - Oak Ridge National Laboratory, Jody Shaw - U. S. Steel
Corporation, and Gustavo A. Aramayo - Oak Ridge National Laboratory
SAE
2001-01-1056
The material
characteristics of High Strength Steel (HSS); such as formability,
strength, ductility, strain-rate sensitivity, and strain hardening,
suggest that HSS has potential to absorb significantly higher amounts of
energy during crashes than conventional low-carbon steel, while reducing
the overall weight of the vehicle. Both studies analyzed a high strength steel intensive vehicle,
with the first assessing the
influence of material modeling approaches on a HSS structure. The second
study evaluated the influence of strain hardening and material thinning on
vehicle crash response; whereas in traditional crash design it has
previously been assumed that these two characteristics negate each other
in crash response. These studies also reviewed the effect of material substitution of a conventional grade of HSS with
an advanced grade of Dual Phase steel.
For the
studies it was assumed that the characteristics of a HSS
structure, with relatively steep strain hardening curves, behave
differently than a structure of mild steel. This lead to the demand for improved
crash prediction which incorporates a more complex material
model. This model also incorporates the use of new technologies,
such as hydroforming, tailor-welding, laser welding, and steel sandwich
materials. Fewer and more slender parts are used a critical
positions, and connections are optimized for weight and transmission of
higher level forces through smaller sections. It is noted that
reduction in structural redundancy for a more optimized
structure requires better control of the collapse of the remaining
structure. Recent
publications have shown that sheet metal forming has measurable effect of
impact performance of automotive components. Even though the forming
effects have been observed to have important effect on a component level,
the effects on the entire vehicle have not been clearly
demonstrated.
This study concluded that crash modeling simulations show a clear effect of
strain-rate sensitivity on HSS intensive vehicles. The influence of
a strain-rate model can be an incremental sensitivity due to the increased
flow stress when similar structure collapse modes are predicted. It
is noted that significant differences in crash energy management capacity
can be predicted if the change in loading on member alters the predicted
collapse mode of the structure. For advanced HSS vehicle designs,
the entire region of material plastic response has to be considered. For
more details of the study, please use the side navigation bar to view
specific areas of study. Each entire publication is available through
the Society of Automotive
Engineers (SAE). The publications numbers are given above, below
the paper titles. The hyperlinks will take you directly to the
purchase site.
|
