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Study on surface treatment for the Strength of bonded joints between CFRP Components

Malmqvist, Theodor LU (2026) MMTM05 20251
Production and Materials Engineering
Abstract
Bonded joints is one of the most common connecting methods between components made from Carbon Fibre Reinforced Polymers, CFRP parts and especially in aviation applications. However, the strength of such bonds is largely affected by the surface preparation, where sanding being the most established but also a very time-consuming option. This thesis investigates the effect that surface preparation has on the single lap shear strength and peel strength of bonded joints between carbon fibre parts. In total three different surface preparations, (method A), (method B) and traditional surface preparation by sanding (BL) are compared for three different CFRP plies. The evaluation is made by comparing the measurement result for single lap SL... (More)
Bonded joints is one of the most common connecting methods between components made from Carbon Fibre Reinforced Polymers, CFRP parts and especially in aviation applications. However, the strength of such bonds is largely affected by the surface preparation, where sanding being the most established but also a very time-consuming option. This thesis investigates the effect that surface preparation has on the single lap shear strength and peel strength of bonded joints between carbon fibre parts. In total three different surface preparations, (method A), (method B) and traditional surface preparation by sanding (BL) are compared for three different CFRP plies. The evaluation is made by comparing the measurement result for single lap SL tensile test and a modified double cantilever beam (MDCB) test. The thesis is performed in collaboration with Blackwing Sweden AB to see if the alternative methods for surface preparation could be suitable substitutions for traditional sanding.

The results show that the shear strength for specimens prepared with method A and B perform equal or better in the single lap shear compared to the traditional method of sanding BL. For peel strength however, method A and B looks to perform equal or slightly worse compared to sanding method BL. The obtained data for peel strength is however insufficient to draw a definitive conclusion and further peel test on corresponding layups as were tested for single lap shear need to be performed. The conclusion has subsequently bridged the gap between R&D and production by further providing information on structural adhesives in industry and its use with CFRP components. (Less)
Please use this url to cite or link to this publication:
author
Malmqvist, Theodor LU
supervisor
organization
course
MMTM05 20251
year
type
H2 - Master's Degree (Two Years)
subject
keywords
CFRP (Carbon Fibre Reinforced Polymer), Adhesive Bonding, Surface Treatment, Lap Shear Strength, Peel Strength
other publication id
LUTMDN/(TMMV-5403)/1-52/2026
language
English
id
9247926
date added to LUP
2026-08-14 09:08:41
date last changed
2026-08-14 09:17:07
@misc{9247926,
  abstract     = {{Bonded joints is one of the most common connecting methods between components made from Carbon Fibre Reinforced Polymers, CFRP parts and especially in aviation applications. However, the strength of such bonds is largely affected by the surface preparation, where sanding being the most established but also a very time-consuming option. This thesis investigates the effect that surface preparation has on the single lap shear strength and peel strength of bonded joints between carbon fibre parts. In total three different surface preparations, (method A), (method B) and traditional surface preparation by sanding (BL) are compared for three different CFRP plies. The evaluation is made by comparing the measurement result for single lap SL tensile test and a modified double cantilever beam (MDCB) test. The thesis is performed in collaboration with Blackwing Sweden AB to see if the alternative methods for surface preparation could be suitable substitutions for traditional sanding.

The results show that the shear strength for specimens prepared with method A and B perform equal or better in the single lap shear compared to the traditional method of sanding BL. For peel strength however, method A and B looks to perform equal or slightly worse compared to sanding method BL. The obtained data for peel strength is however insufficient to draw a definitive conclusion and further peel test on corresponding layups as were tested for single lap shear need to be performed. The conclusion has subsequently bridged the gap between R&D and production by further providing information on structural adhesives in industry and its use with CFRP components.}},
  author       = {{Malmqvist, Theodor}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Study on surface treatment for the Strength of bonded joints between CFRP Components}},
  year         = {{2026}},
}