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Ultrasound Monitoring of CFRP-Aluminum Hybrid Joints

 
: Erdogan, Ezgi
: Herrmann, Hans-Georg; Bechtel, Stephan

:
Volltext urn:nbn:de:0011-n-5436120 (11 MByte PDF)
MD5 Fingerprint: c5aeb1f48d38a2a421849b4c4ae2e08c
Erstellt am: 10.5.2019


Saarbrücken, 2019, IX, 98 S.
Saarbrücken, Univ., Master Thesis, 2019
Englisch
Master Thesis, Elektronische Publikation
Fraunhofer IZFP ()
CFRP; shear horizontal guided ultrasonic wave; EMAT

Abstract
In this work, shear horizontal (SH) guided ultrasonic waves are investigated as a means to monitor adhesively bonded hybrid structures. Aluminium alloy and carbon fiber reinforced polymer (CFRP) single lap joints are produced using co-curing method. Cocuring is a single step joining method, which uses the excess resin from the impregnated laminate to establish the adhesive bonding. SH guided waves are generated and detected by electromagnetic acoustic transducers (EMAT) in a pitch-catch mode. EMATs are placed on the aluminium part of hybrid single lap joint test pieces. First, the initial state of stress free joints are investigated by comparing them to a reference waveform. It is found that the bonding affects the shape and amplitude of the wave packet; thus, carries information regarding the bonding area. Then, the hybrid test pieces are investigated under quasi-static, incremental step and dynamic loading. The results indicate that the failure event can be clearly detected by SH guided wave monitoring. Moreover, gradual change of the waveforms during the incremental step and dynamic loading can be linked to damage propagation of the adhesive joint.

: http://publica.fraunhofer.de/dokumente/N-543612.html