JEC COMPOSITES MAGAZINE - Issue #97 - Special JEC Americas - May/June 2015 - 42

manufacturing

value through production, service and
beyond can be also expected. n
More information:
www.tum.de
References
[1] R. Schledjewski and A. Miaris: Thermoplastic tape placement by means of diode
laser heating, SAMPE Spring Symposium
Conference Proceedings, Baltimore, May 18,
2009 - May 21, 2009.

Fig. 6: Demonstrator design [6] (left); filament wound and fibre placed booster casing demonstrator (right)

nection area transfers the load to the other
segments or the rocket motor. The skirt is required to ensure the connection to the main
stage of the launcher or fairing. Additional
reinforcement of both the skirt and the
connection area is applied by short tracks
in order to withstand the bearing loads of
its connecting elements during launch. The
connection area represents the thickest
laminate of the booster casing, consisting
of 312 layers. The 2.5m long booster casing
demonstrator, with a diameter of 1.3m, is
presented in Fig. 6 on the right.
In order to establish a stable process enabling the lay-up of 312 layers, the various
influencing factors and process parameters
were optimized at the coupon level using
the wedge-peel test. To further improve the
laminate quality and to reduce imperfections such as gaps and overlaps, density
measurements were conducted to evaluate
the porosity at three different locations of
test plates. The overall goal of both process
optimization loops was to maximize the tensile strength of the wound vessel laminate.
Major progress towards process stability of
in-situ TP AFP was achieved by optimizing
hardware components such as the cutting
unit and the compaction roller. Stable processing reduced the error rate and downtime
of the TP AFP machine during manufacturing of the large pressure vessel.
A production time of more than 200
hours and over 25,000 individually placed
tape tracks have proven the stability and

robustness of the process, opening the way
for an industrial use of the in-situ TP AFP
technology. The Technology Readiness
Level (TRL) of this technology is estimated
to be TRL 6 [7].

Future prospects
Currently, strong efforts are made to modify
the TP-AFP head to enable fibre placement
of complex, double-curved structures. Large
structures with low curvatures can already
be produced by TP-AFP. Fibre placement of
skin layers onto thermoformed or metallic
parts is also planned to be extended to more
complex geometries.
In a holistic approach to minimize environmental effects during production, service
and end-of-life repair strategies and recycling
or even reuse concepts for thermoplastic
composite structures need to be considered
and implemented. Disassembly of in-situ
joined thermoplastic composites by induction welding, providing defined heat input
at the fusion zone only, is just one of many
possible prospects. Alternatively, a functionalized layer can be inserted at the joining
zone between two components. For joining
and disassembly, the functionalized layer can
be activated by heat.
To achieve an optimized and efficient process chain in terms of environmental impact
and cost, the key is the implementation of
adapted design guidelines during the early
stage of development of new composite
components. Then, a high gain in economic

42 jec composites magazine / No97 May - June 2015

[2] A. Yousefpour, M. Hojjati and J.-P.
Immarigeon: Fusion bonding/Welding of
thermoplastic composites, Journal of Thermoplastic Composite Materials, Vol. 17, no.
4, pp. 303-341, 2004.
[3] D. Stavrov and H.E.N. Bersee: Resistance
welding of thermoplastic composites - an
overview, Composites Part A: Applied Science and Manufacturing, vol. 36, no. 1, pp.
39-54, 2005.
[4] V. Radlmaier, F. Henne and E. Ladstaetter: Novel environmentally friendly manufacturing approach for thermoplastic composite
helicopter doors, Greener Aviation - Clean
Sky breakthroughs and worldwide status,
Brussels, March 12, 2014 - March 14, 2014.
[5] Department of Trade and Industry (UK):
HYBRIDMAT 3 - Advances in the manufacture of advanced structural composites
in aerospace - a mission to the USA, Feb.
2006, Retrieved April 13, 2015 from http://
depts.washington.edu/amtas/publications/
reports/NCN_HYBRIDMAT-3.pdf.
[6] D. Ducros: Ariane 6 concepts under
investigation, Id 289544, Retrieved April 13,
2015 from http://www.esa.int/spaceinimages/Images/2013/04/Ariane_6_concepts_
under_investigation.
[7] F. Henne, S. Ehard, A. Kollmannsberger,
B. Hoeck, M. Sause, G. Obermeier and K.
Drechsler: Thermoplastic in situ fiber placement for future solid rocket motor casings
manufacturing: SAMPE Europe SETEC 14,
Tampere, September 10, 2014 to September
11, 2014.

http://www.tum.de http://depts.washington.edu/amtas/publications/reports/NCN_HYBRIDMAT-3.pdf http://depts.washington.edu/amtas/publications/reports/NCN_HYBRIDMAT-3.pdf http://www.esa.int/spaceinimages/Images/2013/04/Ariane_6_concepts_under_investigation http://www.esa.int/spaceinimages/Images/2013/04/Ariane_6_concepts_under_investigation

JEC COMPOSITES MAGAZINE - Issue #97 - Special JEC Americas - May/June 2015

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