0.24m thick. Te design follows the same principle as the cargo hatch cover i.e. a number of square hollowed sections on top of each other. Here the study concluded that the
composite bulkhead would, in fact, be of a larger weight than the equivalent steel bulkhead. However: “The calculated bending
deflection of the composite bulkhead will be approximately 0.4m. An analysis of the steel grain bulkhead gives the bending deflection 0.3m. “In this study the bending deflection
and flexural rigidity is the limiting factor. If the requirements of the grain bulkhead are more explicit it will be possible to further optimise the design. Designing
against a strength requirement will result in a significant decrease in weight for this bulkhead. It is recommended to perform further studies.”
Deckhouse scantlings Te core material to be used for deckhouse scantlings in the superstructure in the study was balsa with density 100kg/m3 for all panels, except the first tier of the front bulkhead where the density 279kg/ m3
was used. Te higher design pressure
level demands an increase in core material density for this area. Te fabrics used in the panels are biaxial , (BLT800). All equipment,
0/90 800g/m2
such as windows, doors, doorframes etc., was excluded from the weight calculation.
Copper-bottomed answers New guidance offered on copper-nickel tube and pipe bending.
D
esigners of shipboard piping systems looking for materials offering resistance to seawater
corrosion, high inherent resistance to bio-fouling and good fabrication properties are being reminded that all of the above can be achieved by specifying copper-nickel. A new section on
www.coppernickel.
org, the global site for copper-nickel informat ion, provides in-depth information on tube and pipe bending using these materials. The section provides guidance for
fabricators, installers and operators working with copper-nickel, including the good bending practices and smooth bends that are integral in obtaining the optimum service life of such systems. Offering detailed illustrations of
rotary draw bending and discussing the correction of bending defects, the section provides engineering insight into a subject seldom examined in this manner. The section was written by Maik
Macziek, a technical expert and member of the Copper-Nickel Task Group, a panel of international industry experts. To view the website, visit
www.coppernickel.org and go to System Components, selecting Tube and Pipe Bending of Copper Nickel,
The Naval Architect July/August 2009
The design presented was based on
minimum requirements in accordance to the classification rules. Tis is to be regarded as a baseline for a weight study. The composite weight was given as
10.1tonnes, and therefore the weight saving ratio, in this example, was estimated to be approximately 60% or 15.4tonnes Kockums said that the study showed that it
may be feasible to use composite material in the cargo hatch and the deck house structure without any major changes in the design. “The grain bulkhead design needs to
be adjusted to achieve the most benefit from changing material to composite,” the company said. Further studies within the area will result in a more optimised design with a better weight saving ratio. NA
Guidance for copper-nickel tube and pipe bending gets release.
or go directly to
http://www.copper.org/ applications/cuni/
app_syscomp.html. For those wanting further details of
the applications of copper-nickels, www.
coppernickel.org features an interactive
presentation containing the most crucial and up-to-date information on these workhorse alloys for marine environments, and also addresses many questions on application and best practice. NA
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