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while the authorities raise the safety requirements. All that conflictive demands can only be fulfilled
by combining most advanced engine technology with best aerodynamic shape and high efficient light weight
structures.
The demand for light structural weight can best be reached by applying advanced materials like CFRP with
a high specific strength. This is also the reason while the contingent of CFRP has steadily be increased since
the last 30 years to an actual maximum of ~50% for the coming mid and long range planes B787 and A350
XWB. While cost efficient highly automated CFRP processes are already available for most standard parts
like for the tail planes, fuselage, wing skins, stringers, frames, the floor grid and some other parts, the highly
loaded door surround structure is still planned as differential metal parts as no processes and designs are
available. That means high costs as due to corrosion and fatigue reasons, expensive titanium alloys have to
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be used. Since different projects the DLR Institute Composite Structures and Adaptive Systems is analysing
and developing door surround structures for the use in civil aircrafts. The requirement list is thereby increasing
permanently.
For ensuring the safety of the CFRP door surround structure, in one of the first concepts, the load carrying skin
and frames are rerouted to the inside, giving space for an additional ultra lightweight sandwich impact absorber
structure. This concept is highly optimised in respect to in-service costs, but needs further production cost reduction.
In order to reduce this, a production analysis of all available CFRP processes and designs showed that
instead of a single process a combination of several technologies would lead to a global optimum. To achieve
the highest benefit of each technology, the DLR has combined the Prepreg with the textile technology with skin
and surround structure in one integral one-shot part.
Due to the demand for faster development time and ramp up time, the DLR has developed new concepts for
door surround structures, where the analysis as well as detailed and mould design can proceed mostly parallel.
The logical result of that assumption is, that the door surround structure as well as the moulds should be designed
up-side-down. In case of a later change of the skin thickness or geometry, only a relatively cheap caul
plate must be adapted.
In actual researches the tolerance management is in focus. For solving the tolerance problem at the interface
to the skin, a compromise of integral and differential design gives the best overall solution: Most of the main
frame, secondary frame, intercostals, sill part and longitudinal beam can be manufactured in a one shot solution,
while simple L-profile connectors will be manufactured and assembled separately.
Title: Cold Duct Fan
Authors: L. Cevolini
CRP Technology
Time: November 4, 2009 11:05 am
Room: Lumen
Among the most significant case studies, developed together with our partners, the “Mini Fan”
described in this document is one of my favourite one, as we tried to choose the most suitable
technology and material to push forward for this project.
We could in fact try to manufacture it with several different technologies, such as CNC machining
or through casting with special metal alloys, or even laser sintering of simple PA12 or PA12 glass
filled (we cooperate in fact also with some companies in France that have PA12 and have tested it
for the mini-fan too), but at the end it has been really clear that WINDFORM® XT was the best
choice. Let’s see why.
We can think about a little fan, whose engine power is given by an electric device, instead of 2/4
strokes engine. By extrapolation, we could even call it small mono stage compressor even if in this
case the static pressure increase is very low (no precise data to be released).
Now, without the classic parameters (due to confidentiality), such as efficiency or level of reaction,
which permit to characterize quality of a turboshaft engine, we will try to explain the advantages of
this project analyzing the data provided by our partner: …
Title: Historic Study of Automated Material Placement Equipment
Authors: Mr D. McCarville
Boeing
Time: November 4, 2009 11:25 am
Room: Lumen
As the commercial aircraft industry attempts to improve airplane fuel efficiency, large airframe components like
wing skins and fuselage barrels are shifting from aluminum to composites. As a result, there is an increased
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demand for automated material placement (AMP) equipment capable of making large and small highly sculptured
parts. Existing texts and scholarly articles concerning AMP equipment are typically limited in scope to
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