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ReseaRch PRogRammes
The need for multi-material structures in the automotive,
offshore and physical security industries is becoming
increasingly important to meet the requirements in terms of
performance and weight reduction of their products. Often, the
behaviour of a structure is strongly linked to its connections
and its capacity to sustain and transfer the applied load to its
different members. In this perspective, the design of multi-
material structures using numerical simulations has to take
into account how the connections will behave and fail. Today,
large shell elements are used for computational efficiency
which hampers an accurate representation of the connections
and their failure modes due to a poor discretization of these
complex problems.
The aim of this research programme is to provide macroscopic
models for multi-material connections which are based on
a fundamental understanding of the structural joints. These
models should be industry-friendly in terms of computational
time as well as the calibration cost. Here, multi-material
connections involve a combination of aluminium, steel and
fibre reinforced polymers.
The objective of the programme is fulfilled by using a
multiscale testing and modelling strategy. This strategy
involves testing at different scales from the material within
the connector, through single connector tests, to the final
component level. Each of these testing levels is important
to gain a fundamental understanding of the connections of
interest. In terms of numerical modelling, mesoscopic models
where the connections are represented by solid elements
will be employed to increase knowledge of the behaviour and
failure of structural joints. However, macroscopic models are
the final outcome of the programme.
In 2016, a PhD project was launched with the PhD candidate
Matthias Reil, who is funded by BMW and CASA. The topic of
his work is joining of steel and aluminium using structural
bonding and self-piercing rivets. His project will have strong
focus on the virtual testing of these connections and the
calibration of industry-friendly macroscopic models.
Moreover, three other PhD students were involved in the
research programme in 2016:
• Johan Kolstø Sønstabø is working on the behaviour and
modelling of Flow-Drill Screw connections in aluminium
structures. (Funded by Honda Americas, started in 2013.)
• Erik Løhre Grimsmo is working on the behaviour and
modelling of bolted and welded connections. (Funded by SFI
SIMLab, started in 2013.)
• John Fredrick Berntsen is working on the behaviour and
modelling of multi-material connections. (Funded by SFI
CASA, started in 2015.)
In 2016, PhD candidates Matthias Reil and John Fredrick
Berntsen characterized their respective structural adhesives
using the same procedure as that developed by the Polymeric
Materials research programme, Figure 8. During the spring
2016, PhD candidate Johan Kolstø Sønstabø spent three
months at Honda R&D Americas to implement some of the
results from his PhD into an industrial environment.
Structural Joints
Head of Programme: David Morin
Figure 8: Characterization
procedure of structural adhesives.