Failure analysis of adhesively-bonded metal-skin-to-composite-stiffener

Failure analysis of adhesively-bonded metal-skin-to-composite-stiffener: Effect of temperature and cyclic loading

Teixeira De Freitas, S. (TU Delft Structural Integrity & Composites)
Sinke, J. (TU Delft Structural Integrity & Composites)

2017-04-15

The aim of this research is to analyse the failure of a Fiber Metal Laminate (FML) skin adhesively bonded to a Carbon Fiber Reinforced Polymer (CFRP) stiffener, under quasi-static loading at different environmental temperatures (−55 °C, Room Temperature RT and +100 °C) and under fatigue loading at RT. This bonded joint was tested using stiffener pull-off tests, which is a typical setup used to simulate full-scale components subject to out-of-plane loading. The failure sequence for all test conditions consist of: (1) damage initiation at the noodle of the CFRP stiffener; (2) damage propagation by delamination from the noodle to the stiffener foot; (3) detachment of the stiffener from the skin. Increasing the temperature, decreases the joint stiffness (40% when compared to RT) and decreasing the temperature decreases the maximum load (50% when compared to RT). The fatigue life initiation of the joint presents a very large scatter but the fatigue life propagation presents more stable results. The fatigue threshold (no damage) is reached at approximately 30% of the maximum load level. The fracture surfaces indicate a predominant inter and intra-laminar failure of the composite under mixed mode I/II. The CFRP stiffener is the weakest link of the bonded FML-skin-to-CFRP-stiffener both for static and fatigue loading.

composite-to-aluminium joints
fatigue
Keywords: Adhesive bonding
skin-to-stiffener connection
thermal loading

http://resolver.tudelft.nl/uuid:23d93eb4-31d3-4309-8e00-dbe9fde6bfc3

https://doi.org/10.1016/j.compstruct.2017.01.027

2019-01-28

0263-8223

Composite Structures, 166, 27-37

Institutional Repository

journal article

© 2017 S. Teixeira De Freitas, J. Sinke