JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015 - 43

higher than the calculated one. This could be due to the approach
taken, which assumes areas with voids have a tensile shear strength of
zero, which is perhaps too conservative. A comparison of the joining
areas shows that, for all processing speeds, the calculated joining area
predicted by the simulation corresponds pretty well with the real
joined area.

Conclusions and outlook

Fig. 7: Comparison of simulated and measured tensile shear strength

the thermal simulation, however, all the bodies were simplified and
considered as homogeneous.
The tensile shear strength of Specimens 2 and 3 is higher than the
tensile shear strength of Specimens 1 and 4, which are positioned at
the beginning and at the end of the joined organic sheet with a length
of 100 mm. The inherent edge effect of induction heating influences
the heat-up characteristics at these positions. Due to edge effect
heating pattern changes and heating efficiency in the run-in and
run-off area, the actual tensile shear strength for each case is lower
than calculated. Therefore, the welding process needs to be adjusted
and optimized to consider the edge effects and other irregularities in
order to increase the bonding strength of the entire welded joint.
For a process feed of 200 mm/min and 350 mm/min, the tensile
shear strength of Specimens 2 and 3 corresponds well with the calculated tensile shear strength level. In this case, the simulation provides
a realistic view of the expected bonding strength. As opposed to
this, the tensile shear strength for a process feed of 450 mm/min is

The present work has shown that the user interface was verified in
good accordance of the predicted weld strength. In addition, an induction welding head for a robot and appropriate system technology
were developed to transfer the results gained from test rig investigations into a real automated process. By means of the developed process optimization tool, a demonstrator was joined with a parameter
set chosen using process diagrams generated by the user interface
(Fig. 8). Due to these results, the application of the user interface is
confirmed. Within prospective investigations, various fabric structures will be analyzed to determine the influences of textile parameters concerning their heating-up behaviour due to induction heating.
Based on these results, the laminate structure of the joining partners
will be adjusted to generate a higher energy input into the joining
zone compared to near-surface areas. In order to achieve higher process speeds, alternative cooling methods will be investigated and the
gained results will be implemented in a revised simulation tool. This
way, the end-user will be able to obtain the appropriate parameters
required in a quick and easy way. This work has demonstrated a tool
to improve the competitiveness and efficiency of the continuous
induction welding process for thermoplastic CFRPCs. n
References
[1] P. Mitschang, D. Maurer, Quality Controlled Induction Welding
by adapted Process Parameters, in: SAMPE Baltimore, Baltimore,
18-21.05.2015.
[2] L. Moser, Experimental analysis and modeling of susceptorless
induction welding of high performance thermoplastic polymer composites, Institut für Verbundwerkstoffe GmbH, Kaiserslautern.
[3] M. Duhovic, I. Caldichoury, P. L'Eplattenier, P. Mitschang, M.
Maier, Advances in Simulating the Joining of Composite Materials by
Electromagnetic Induction. In: Proceedings of the 9th European LSDYNA® Users Conference, Manchester, 2013, Electromagnetic (2).
[4] R. Rudolf, Entwicklung einer neuartigen Prozess- und Anlagentechnik zum Fügen von thermoplastischen Faser-Kunststoff-Verbunden. Zugl.: Kaiserslautern, Univ., Diss., 2000. Kaiserslautern: Institut
für Verbundwerkstoffe GmbH (IVW-Schriftenreihe. 10).
Acknowledgments
The presented work was conducted in cooperation with 'PFAFF
Industriesysteme und Maschinen GmbH, Zweigniederlassung KSL'
in the project 'AutoIndu' (funding code KF2088325WO3), funded by
the German federal ministry for economy and energy.

Fig. 8: Automatable induction welding system for the continuous induction
welding of carbon fibre-reinforced thermoplastics and the demonstrator joined
using the user interface

No101 November - December 2015 /

More information:
www.ivw.uni-kl.de
stephan.becker@ivw.uni-kl.de

jec composites magazine 43

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Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015