Sandwich panel

Not to be confused with sandwich plate system.
Aluminium composite panel structure
Construction site panel made of aluminium composite panel (detail view)
Construction site panel made of Dibond

A sandwich panel is a structure made of three layers: low density core inserted in between two relatively thin skin layers. This sandwich setup allows to achieve excellent mechanical performance at minimal weight. The very high rigidity of a sandwich panel is achieved thanks to interaction of its components under flexural load applied to the panel: core takes the shear loads and creates a distance between the skins which take the in-plane stresses, one skin in tension, the other in compression. General information on sandwich panel structure, different sandwich core types available and the potential with respect to weight savings is available in the following reference.[1]

Honeycomb sandwich panel has been proven as the most efficient sandwich design with respect to mechanical performance and weight. Aerospace and aircraft industry uses the honeycomb structures as they meet the tough requirements of related applications. The use of honeycomb sandwich design in more common applications has been more limited due to the batch wise manufacturing processes and hence relatively high production costs.

This trend has been changed after the company EconCore developed a continuous process of honeycomb production under the brand name ThermHex.[2] Cost efficiency of the ThermHex process, which has been licensed by number of companies over the world, allows a very cost effective production of sandwich panel with thermoplastic honeycomb core for applications in even cost sensitive market segments such as packaging, automotive, or building & construction.

Aluminium composite panel (ACP), also aluminium composite material (ACM), is a type of flat panel that consists of two thin aluminium sheets bonded to a non-aluminium core. ACPs are frequently used for external cladding or facades of buildings, insulation, and signage.[3] If the core material is flammable, usage may be problematic as a building material and some jurisdictions have banned their use.[4]

Aluminium sheets can be coated with polyvinylidene fluoride (PVDF), fluoropolymer resins (FEVE), or polyester paint. Aluminium can be painted in any kind of colour, and ACPs are produced in a wide range of metallic and non-metallic colours as well as patterns that imitate other materials, such as wood or marble. The core is commonly low density polyethylene, or a mix of low density polyethylene and mineral material to exhibit fire retardant properties.[5]

3A Composites (formerly Alcan Composites & Alusuisse) invented aluminium composites in 1964 and commercial production of Alucobond commenced in 1969, followed by Dibond 20 years later.

Design

J. M. Davies, Mohammed Rahif Hakmi, and P. Hassinen conducted a series of early researches into numerical, experimental behavior of materials and fire and blast behavior of composite material. They published multiple research articles on the following subjects:

Applications

Sandwich panels are used in applications where high structural rigidity and low weight are required. An evident example of use of sandwich panels is aircraft, where mechanical performance and weight saving is essential. Other applications include packaging (e.g. fluted polypropylene boards of polypropylene honeycomb boards),[15] transportation and automotive[16] as well as building & construction.[17]

ACP is mainly used for external and internal architectural cladding or partitions, false ceilings, signage, machine coverings, container construction, etc. Applications of ACP are not limited to external building cladding, but can also be used in any form of cladding such as partitions, false ceilings, etc. ACP is also widely used within the signage industry as an alternative to heavier, more expensive substrates.

Epcot's Spaceship Earth is an example of the use of ACP in architecture. It is a geodesic sphere composed of 11,324 ACP tiles.

ACP has been used as a light-weight but very sturdy material in construction, particularly for transient structures like trade show booths and similar temporary elements. It has recently also been adopted as a backing material for mounting fine art photography, often with an acrylic finish using processes like Diasec or other face-mounting techniques. ACP material has been used in famous structures as Spaceship Earth, VanDusen Botanical Garden, the Leipzig branch of the German National Library.[18]

These structures made optimal use of ACP through its cost, durability, and efficiency. Its flexibility, low weight, and easy forming and processing allow for innovative design with increased rigidity and durability.

Other names

Many people use Alucobond or sandwich panel as a generic name (genericized trademark) for aluminum composite panels that are typically 0.19 mm thick aluminum sheets covering a solid polyethylene core with a total thickness of 3 to 6 mm or more, or similar panels from any manufacturer.[19]

A variety of manufacturers sell aluminium composite panels under a wide variety of brand names.

Some people use sandwich panel for any structural sandwich (sandwich-structured composite) of a core bonded between two cover sheets,no matter what material(s) it is made of, and no matter if the core is solid, foam, flutes, or honeycomb.[20]

See also

References

  1. ↑ "Sandwich Panel Technology". EconCore.com. Retrieved 2014-10-03.
  2. ↑ "ThermHex honeycomb technology". EconCore.com. Retrieved 2014-10-03.
  3. ↑ "Architectural Metal Designs-Products". Architectural Metal Designs. Retrieved 2014-06-18.
  4. ↑ Walker, Alissa. "When Will Dubai Fix Its Burning Skyscraper Problem?". Gizmodo. Gawker Media. Retrieved 2016-01-06.
  5. ↑ "Architectural Metal Designs-Products". Architectural Metal Designs. Retrieved 2014-06-18.
  6. ↑ "Dr. Mohammed Rahif Hakmi's Research".
  7. ↑ "Local Buckling of Sandwich Panels".
  8. ↑ "Local Buckling of Profiled Sandwich Plates", Davies, J.M. & Hakmi, M.R., Proc. IABSE Symposium, Mixed Structures including New Materials, Brussels, September 1990, pp. 533-538
  9. ↑ "Local Buckling of Profiled Sandwich Plates".
  10. ↑ "Face buckling stress in sandwich panels", Davies M J and Hakmi M R, Nordic Conference Steel Colloquium, pp. 99-110 (1991)
  11. ↑ "Postbuckling behaviour of foam-filled thin-walled steel beams", Davies, J.M., Hakmi, M.R. and Hassinen, P., Journal of Constructional Steel Research 20: 75 - 83 (1991)
  12. ↑ "Fire resistance of composite floor slabs using a model fire test facility", ABDEL-HALIM, M. A. H. (1); HAKMI, M. R. (2); O'LEARY, D. C. (2). Authors' affiliations: (1) Department of Civil Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid, JORDANIE; (2) Department of Civil Engineering, University of Salford, Salford, M5 4WT, ROYAUME-UNI.
  13. ↑ "Fire-Resistant Sandwich Panels for Offshore Structures", Professor J. M. Davies, Dr. R. Hakim, Dr. J. B. McNicholas, University of Salford, CP07 in "The Cost-Effective Use of Fibre-Reinforced Composites Offshore", HSE Research Report 039, 45 pages
  14. ↑ "Numerical Temperature Analysis of Hygroscopic Panels Exposed to Fire", Davies, J.M., Hakmi, R. and Wang, H. B., p1624-1635, Numerical Methods in Thermal Problems, Vol. VIII Part 2, Proceedings of the Eighth International Conference Held in Swansea, July 12-16th, 1993, Pineridge Press, UK.
  15. ↑ "Packaging sandwich panels". Karton.it. Retrieved 2014-10-03.
  16. ↑ "Gorcell by Renolit". Renolit.com. Retrieved 2014-10-03.
  17. ↑ "Stinger honeycomb panel". coroplast.com. Retrieved 2014-10-03.
  18. ↑ "ALUCOBOND® A2". Alucobond. Retrieved 2013-01-31.
  19. ↑ "Alucobond: The name says it all". Retrieved 2014-06-18.
  20. ↑ "Delron Inserts for Honeycomb and Sandwich Panels" (pdf). Retrieved 2013-01-31.

External links

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