A car or a truck contains a
lot of sheet metal product (over 300 parts). In general,
these parts are manufactured by a deep drawing process.
However, during the last decade, a new production process
with high potential is increasingly used to manufacture
these sheet metal parts. This process is called
hydroforming
In the hydroforming
process parts are formed using a rigid die and a fluid
under high hydrostatic pressure. It is used for the forming
of tubular parts and flat sheets. In tube forming a
pressure is applied in the interior of the tube and often a
mechanical compressive force is exerted in the axial
direction (end feeding). The combination of compressive
axial stresses and circumferential tensile stresses
facilitates the deformation up to high strains because
necking is postponed by the axial compression. As a result,
the hydroforming process offers the ability to manufacture
products with very complex shapes which entails a high
styling potential for product designers. Examples of
automotive product, fabricated by tube hydroforming are
roof rails, engine cradles and exhaust manifolds.
During Hydroforming
many failures like wrinkling, buckling, folding back and
bursting are frequently experienced. To investigate these
failure mechanisms, several test geometries are defined,
such as the free expansion test. The finite element method
is used to validate the experimental results of the test
geometries. Then, the validated model will be used to
identify the typical failures modes that can occur during
the hydroforming of a T-Piece and other related
hydroforming products. After identifying the failure modes
a true understanding of the failure mechanism can be
studied. This understanding should result in potential
solutions of hydroforming failures.
When the quality of the
hydroforming is good enough, simulations can be used as a
tool to check the manufacturability (robustness) and
geometry of the desired part. To be able to achieve an
optimal process, several geometric and parameter variations
like end feeding must be investigated. Currently, this
requires a lot of expensive and time-consuming manual work,
based on experience. Due to the use of new materials and
production processes, it becomes more and more difficult to
find the optimum process settings. Therefore there is a
strong need for an algorithm which is able to find the
optimum settings for sheet forming processes. Nowadays,
research on this topic is in full swing.
Anthology of finished graduate projects:
Industrial partners: