Adhesively Bonded Steel Sandwich Structures for Marine Applications

Konstantinou, Eleni A (1996) Adhesively Bonded Steel Sandwich Structures for Marine Applications. MSc(R) thesis, University of Glasgow.

Abstract

Sandwich panels, consisting of two facing plates separated by a core of stiffeners, are known to possess high strength and high stiffness to weight ratios. This form of construction is appropriate for structures where the self weight is one of the governing design criteria. This is particularly applicable in cases where the self weight could be reduced while the strength is maintained. The present study deals specifically with the understanding of the performance of adhesively bonded steel corrugated core sandwich structures used for marine applications under realistic loading, namely bending and axial compression. That was done through review on the relevant subjects, theoretical work as well as experimentation. Review on the subjects of adhesion, adhesives, sandwich construction, theory of sandwich construction and the concept of structural connections within the field of sandwich construction are concisely covered from Chapter 1 to Chapter 4, giving in a rather informative way the main outline of each aforementioned subject. As far as the experimental part is concerned, ten models were manufactured especially for the purposes of the present study. More specifically, their components - namely the flat plates and the webs - were joined together by means of a structural adhesive. Therefore, this study demonstrates - and this is clearly shown from Chapter 5 to Chapter 6 - that any failure occurring at this kind of structures is due to buckling either of the flat plate or the web, instead of being due to failure of the adhesive bonding. Two types of bending tests were performed: four point and three point bending tests. Buckling of the webs and any other deformation occurred only adjacent to the points of load application causing some local but not global adhesive and further model damage. Besides, none of the models collapsed. Prediction of the stresses conforms to simple beam theory, although there seem to be some discrepancies between theoretical and experimental values. These could be attributed to imperfections occurring during the manufacture of the models, the material properties from which they are constructed, the installation of the strain gauges, the measuring of the strain gauge values and the important fact that both kinds of bending tests followed either the creep or compression tests. The four point bending tests revealed that the adhesive can influence the performance of the models. In a few words, in terms of real life performance, the strength of the adhesively bonded corrugated core sandwich structures can be seriously affected by the creep of the adhesive. This performance seems to be common for any corrugated core structure irrespective of the combination of face and core geometry. This would seem to preclude use of such structures where significant continuous loading is concerned (for example, heavy weights on deck structure). In contrast to what happens in bending, in compression of this type of structures theory agrees almost perfectly with experiments and this happens mainly because a lot of serious studies have been done in the past by a number of scientists as far as this matter is concerned which results in small deviations to exist. Buckling of the faces and any other deformation occurred only adjacent to the points of load application causing some local but not global adhesive debonding. In conclusion, the model structures designed for the purposes of the present project proved to be stable and strong. The concept of adhesively bonded steel corrugated core sandwich structures specifically designed for marine applications is still new and is worth developing much further by encouraging further research. The findings of the present work have been set all together in Chapter 7 and a number of interesting conclusions accompanied by proposals for future research work appear in Chapter 8.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: Ian E Winkle
• Keywords: Naval engineering
• Date of Award: 1996
• Depositing User: Enlighten Team
• Unique ID: glathesis:1996-75593
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 19:21
• Last Modified: 19 Nov 2019 19:21
• URI: https://theses.gla.ac.uk/id/eprint/75593