149
Through Optimum Use and Innovation of Welding and Joining Technologies
Improving Global Quality of Life
A380) laser welded (skin-stringer) panels are used and efforts are being made to increase the use of such
components in future aircraft (
Figure 9.14
).
The challenge, however, is coming from reinforced composite
materials technology and competition between the welded metallic option and composite structure for cost
and weight savings will decide future aircraft technologies. This trend and development are accompanied
with the differences in damage tolerance performances of both manufacturing routes (
Figure 9.15
).
Welding technologies together with new weldable high strength Al-alloys and with the use of “local
engineering” are capable to generate damage tolerant, safe components. This position, however, needs
to be maintained or reinforced with numerous scientific and technological developments in design and
improvements in understanding of the damage tolerance behaviours. It is expected that the major challenge
will be in the development of advanced joining technologies for the fabrication of “material-mix” or “multi-
material” (e.g. metal-composite components) of future airframe structures.
Development of new filler wires beyond currently used 12%Si containing wires for LBW process will
significantly contribute to the potential use of the welded airframe panels.
Additionally, new developments in design, inspection (structural health monitoring), fatigue and fracture
aspects will enhance the competitive position of the welded Al-alloy airframe components against adhesively
bonded composite structures.
In addition to the current use of laser beam welding technology in lower shell regions of the European
commercial aircraft, such as the A380, A340 and A318, side and upper fuselage regions of these aircrafts
should be new application targets for welded fuselage assemblies. Design requirements of upper fuselage
parts, however, are different from lower shell regions and hence higher damage tolerance properties are
needed for the welded skin-stringer assemblies. This will be a new challenge for the welding mechanics.
In addition to the challenges of LB welding of thin-walled Al-airframe structures, described above, the
following topics are considered as major areas of interest in aerospace applications.
9.18.1
Hot topics
Dissimilar materials joining
:
The drive towards maximum structural efficiency is pushing the need
for joining technology for dissimilar materials. Such joints allow point-to-point optimisation of
material properties, including strength to weight ratio, high temperature stability, etc. Riveting
results in point load stress management and corrosion potential, adding weight and cost while
reducing reliability and lifetime. Adhesive bonding and other joining methods, including welding,
soldering, and brazing, offer alternatives for structural efficiency and increased temperature
performance. NDE of joints combining complex material arrays requires updating and development.
Figure 9.15
Trends in use of welded panels
for European aircraft A380, A340 and A318.
(
Reproduced courtesy: AIRBUS)
9
Needs and challenges of major industry sectors for future applications
