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FP5

BONDSHIP Sintesi della relazione

Project ID: G3RD-CT-2000-00101
Finanziato nell'ambito di: FP5-GROWTH
Paese: Switzerland

Adhesive test results from Sika

In the screening tests 5 adhesives on 19 surfaces with different pretreatment methods were tested, in respect to the demands from the shipyards. For the most applications a practical solution was developed. The flexible Sikaflex adhesives can bond on the most surfaces with the correct SikaPrimer. But the substrate needs always a corrosion protection; the bonding directly on raw metal is poor, especially for steel. Always very good results were achieved with the two component shop primers that are normal suitable at shipyards. The best way for qualification a flexible bonding system and correct surface preparation is the bead adhesion peel test. The results of this were also supported by lap shear tests, and later on with the ageing and fatigue tests.

In the ageing and fatigue testing single overlap shear joints with 3mm bond thickness were tested with an alternating cyclic loading by a stress ratio of R = -1 with a test frequency of 25Hz. This results a negative minimum stress with the same amount as the maximum stress, and the mean stress is zero. The results show that the fatigue durability is above 0.2MPa, and below 0.45MPa for Sikaflex-552, respective below 0.25MPa for Sikaflex-292. After two million cycles with 0.2MPa no weariness was detectable and the measured compliance was all the time constant.

There was also no influence of the 1600 hours salt spray ageing detectable, compared to the not aged samples. If some corrosion occurs, it happens between the Primer and the aluminium (Anticorodal-110 EN AW-6082 T6), the adhesive was not influenced. The samples loaded with 2 million cycles at 0.2MPa and 1600h salt spray were ruptured in the tensile lap shear test and compared to not aged samples. The measured change of mechanical properties was very small.

The test results will be used for further consultation in the transportation industry. Most of the examined surfaces are suitable in many other industrial applications, with exception of the two-component shop primer, which is typically only used in shipbuilding. The tested loading and ageing conditions are also very common.

Contatto

Stephan KOCH, (Head of Material Mechanics)
Tel.: +41-14-364713
Fax: +41-14-364444
E-mail