Fraunhofer-Gesellschaft

Publica

Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Effect of surface treatment for metallic z-reinforcements on interlaminar fracture toughness of CFRP/CFRP joints

 
: Jürgens, M.; Kurtovic, A.; Mertens, T.; Nogueira, A.C.; Lang, H.; Kolb, M.; Strobach, P.; Hombergsmeier, E.; Drechsler, K.

Beckwith, S.W. ; Society for the Advancement of Material and Process Engineering -SAMPE-:
SAMPE Baltimore 2015. Conference & Exhibition. CD-ROM : May 18 - 21, 2015; conference, May 19 - 20, 2015: exhibits, Baltimore Convention Center, Baltimore, Maryland
Covina/Calif.: SAMPE, 2015
ISBN: 978-1-934551-19-6
13 pp.
Society for the Advancement of Material and Process Engineering (SAMPE Conference & Exhibition) <2015, Baltimore/Md.>
English
Conference Paper
Fraunhofer ICT ()

Abstract
The weight saving potential of carbon fiber reinforced polymers (CFRP) in primary aircraft structures is strongly determined by the applied joint design. Through-thickness reinforcements (z-reinforcements) are introduced to increase the delamination resistance of laminates and joints and thus improve their damage tolerance. In the present work, an innovative process is presented for a cost and time-efficient manufacture, with multidimensional metallic structures enhancing the joint's interlaminar fracture toughness. Spikes bent in the out-of-plane direction made of stainless steel and titanium were exposed to wet-chemical (HF/HNO3, Turco 5578®) and physical (pulsed laser irradiation; Nd:YVO4, 1064 nm) surface treatments to create micro-and nano-scaled oxide layer morphologies respectively. Mode I energy release rate is improved significantly through the introduction of pretreated reinforcements into a double cantilever beam (DCB) joint geometry. Laser irradiation shows a superior performance when compared to alkaline etched or baseline sandblasted spikes. Surface analyses through SEM and XPS were employed to further correlate fracture mechanical results to the oxide surface morphology, chemical composition and surface contaminations resulting from the applied co-bonding process. Reference joints featuring pretreated sheets without spikes in the bondline reveal similar results.

: http://publica.fraunhofer.de/documents/N-442196.html