On right: photo of Kirin Fire can from Christian Kadluba’s Flickr Photostream
“Fire” is a canned coffee — one of a number of products from Kirin that are packaged in a faceted “diamond cut” can. More familiar to consumers in Japan, this is a type of can that Toyo Seikan has been manufacturing since 2001.
Comparing its pattern to some other soda cans we’ve considered in the past — the 1966 harlequin patterned Coke cans and Jorge Ubeira’s series of hand-bent Diet Coke cans — one might reasonably wonder whether there is something geometrically inherent in cylinders that makes this pattern particularly suitable for cylindrical packaging.
As it happens, Toyo Seikan’s “diamond cut” can pattern derives from research at the “Institute of Space and Aeronautical Science” in Tokyo: Koryo Miura’s 1969 paper, Proposition of Pseudo-Cylindrical Concave Polyhedral Shells.
As Toyo Seikan’s own website states:
The three-dimensionally structured truss (triangular framework structure) design, called a “PCCP shell” (Pseudo-Cylindrical Concave Polyhedral Shell), was developed during the process of space engineering research. It was incorporated into the can processing technology to produce diamond cut cans.
Miura’s insight was that the roughly geometric patterns that naturally occur on the sides of compressed or “buckled” cylinders are not simply “failed forms,” but rather, “the basic forms of a new shell which could function superbly…” — and recognized that the basic pattern which cylinders naturally tended to exhibit (when axially compressed) was the “Yoshimura pattern.”
Professor Y. Yoshimura had previously noted the geometric characteristics of buckled cylindrical shells in his 1955 paper, On the mechanism of buckling of a circular cylindrical shell under axial compression for the National Advisory Committee on Aeronautics:
“The reason why the cylindrical shell reveals such a particular behavior for buckling will be attributed to the geometrical features of its deformation, that is, to the fact that a developable surface quite different from the original cylindrical surface can exist. On the basis of these fundamental concepts concerning deformation and energy, the mechanism of the buckling can be understood more completely.”
…and he then went on to describe what is now known as the “Yoshimura pattern.”
via: Bravis International
While many have marveled at this practical application of aerospace technology to quotidian soda-can packaging, the fact is, that seamless beverage cans were an important part of the research from the very beginning.
(More about pseudo-cylindrical concave polyhedral packaging, after the fold…)
The Horton method:
One simple method, originated by Horton at Stanford University, in the early sixties, for obtaining accurate isotropic cylindrical shell specimens inexpensively is the use of seamless beer or soft drink cans. Since these thin-walled cans have to be within the close tolerances demanded by the automated filling and sealing process, they represent a source of specimens with accurately repeated dimensions. Recently this idea has been revived by Arbocz and Elishakoff at Delft University of Technology in a test program related to stochastic stability analysis and at the Technion Aircraft Structures Laboratory in a test program on buckling of shells under axial impact. A special production run of empty steel beer cans without paint and without closing lids has been made, yielding specimens with (R/t) = 300. The shells have, however, an integral bottom end closure, which has to be removed, some axisymmetric thickness variations with height and quite significant residual stresses. These have to be studied further for more precise evaluation, but even now, though undefined, they are practically identical for the many specimens made by the process.
Experimental Methods in Buckling of Thin-Walled Structures
By J. Singer, J. Arbocz, T. Weller
More recently, Jan de Vries cited the extensive use of beer cans as specimens at Delft University of Technology’s laboratories, in his 2009 thesis entitled, “The Imperfection Data Bank and its Applications.”
His introduction begins with this poetic entry, empathetically written from the point of view of an anthropomorphic beer can whose shelf life was so drastically altered by rocket science:
The beer can was denied its original purpose in life. Before it got to the filling station in the beer plant, it got removed from the machine to be of use in the investigation of imperfection sensitivity of thin-walled shells. As it found out what was going to happen, the beer can reconsidered what to do. It could not taste the beer it had waited for for so long. However, this was not an unrealistic thought. Serving as a container for some liquid, whilst not being able to drink, and waiting for some person to come along and empty you and then get thrown out of the window if you were unlucky, or get recycled if you weren’t. No, one had to look for new opportunities. What was this imperfection sensitivity all about? Thin-walled shells, that is me, it thought. Am I alone in this world or are there more like me? Yes, I know lots of fellow beer cans. Even some vague far away families who prefer cola or orange juice even. But they are all small like me. The can then found out that there are huge shells, dinosaur tall compared to him, but not extinct. They did not contain stuff like beer, or coke, but very interesting sounding stuff like LOX or LH2. The can did not know what kind of stuff this was, but realized this: these big brothers were about to fly to the moon, to Mars or even maybe out of the solar system. No short life time, no low mile coverage, no, just your ordinary Saturday evening getting sold, getting drunk and getting thrown away. These guys really went somewhere. Now this was something to think about. The little can thought that even though he could not fly into space, it would also mean a lot to him if he could in some way help his big friends to safely fly into the sky.
Jan de Vries
The Imperfection Data Bank and its Applications
One more thing: as a pattern based on the geometry of collapsing cylinders, it’s not surprising that one of a myriad of patents for collapsible beverage containers, includes one based on the Yoshimura pattern…
Robert W. Hyde’s 1975 “Collapsible Can” patent
And while we’re at it, here’s the 1992 patent assigned to Toyo Seikan, covering the similarly structured, diamond cut can pattern…
For more “Pseudo-Cylindrical Concave Polyhedral” packaging see: Polyhedral Soda & Chips