Material Model for Deformation and Failure of Cast Iron
for High-Speed Impacts
Hartmut Chladek, INPROSIM GmbH
Cast iron parts have been used for a wide range of applications
in mechanical engineering for a long time. Nowadays, due to
their design flexibility and low costs, cast parts are increasingly
utilised for very high loadings, e.g. in automotive and aircraft
industry, turbo machinery as well as wind energy and generating
plants. In case of an accident such as a car crash, an aircraft
emergency landing, a turbine burst, etc. highly dynamic impacts
occur. These highly dynamic loadings of cast parts can be
handled by an explicit simulation code such as RADIOSS.
Due to the highly dynamic loads which lead to extreme deformation
and failure, the former standard of using a simple material
law for cast iron resulting from a standard tension test is
no longer sufficient. The strain rate dependence and the influence
of temperature and dynamic hardening have to taken into account
as well as the different failure effects for tension, compression
and shear loading. RADIOSS handles this demand in a comfortable
way by a standard material law which can be enhanced by an
additional failure criteria card.
This presentation gives an overview of how to describe the
deformation and failure of cast iron for high speed loading
in RADIOSS. Starting with tension, compression and shear testing,
it shows the implementation into a standard material law using
the additional failure criteria card, thus explaining the
stress triaxiality within the Johnson-Cook failure. These
effects are demonstrated by the simu-lation of an impact test
of a bullet onto a plate and comparison of the results with
and without additional failure specification. The presentation
concludes by showing the containment simulation of a turbocharger
as an example for the achieved enhancement in material description
of cast iron.
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