New Composite Rules for lighter, faster and more fuel efficient ships

In the last two decades, the use of composites has grown considerably. Starting in aircraft and the power car industry, they have become a key feature of the shipbuilding industry. In order for LR to remain at the technological cutting edge, a Composite Rules Update Workgroup was formed consisting of Special Service Craft and composite materials experts from LR and MARTEC. Since 2008, a great deal of work has been carried out in order to update LR’s SSC Composite Rules.

These new upgraded SSC Composite Rules open the possibility for our clients to design LR compliant ships which are lighter, faster and more fuel efficient than ever. Lighter and more fuel efficient craft makes new propulsion technologies possible, like Li-ion battery powered ships, new generation hovercrafts and Wing in Ground effect craft. At the same time, conventional technologies become more efficient and environmentally friendly.

The following items have been updated:

“Generic” material properties updated with the latest testing results. Advanced materials, as carbon fibre and Aramid added to the properties tables.
Mechanical properties of the marine plywood panels added to assist builders in early design stages.
Sandwich panel skins minimum thickness requirements replaced by minimum weight of reinforcement. Minimum weight of reinforcement made dependant on length of craft in order to make SSC rules more suitable for craft below 24m length, especially high speed craft.
Local skin wrinkling criteria has been added for sandwich skins
Slamming pressure correction added for panels exposed to slamming loads
Deflection of sandwich panels formula revised to take shear stiffens of the core in account. The calculated deflections are more realistic (less onerous) than previous ones.
Panel Deflection limits revised in order to take in account composite material elastic modulus and position of panel in question.
A number of archaic and out-of date requirements has been removed from the Rules. SSC software has been updated to reflect the changes.
Source: Lloyd’s Register