ClassNK releases guidelines for membrane systems on LNG carriers

Classification society Nippon Kaiji Kyokai (ClassNK) has released its guidelines for membrane systems on liquefied gas carriers.

ClassNK said that the guidelines specify the technical requirements
for evaluating structural strength using finite element analysis when designing
membrane-type liquefied gas carriers.

As with the society’s other guidelines for structural
strength evaluation, they are based on ClassNK’s evaluation technology for the
wave load acting on the hull and outline the requirements to be considered for
the structural strength of membrane-type liquefied gas carriers along with
related rules to support rational and efficient designs.

The guidelines are composed of the guidelines for direct strength
analysis which specify the requirements for evaluating the yield and buckling
strength of the net scantlings of the primary structural members by direct
strength calculation, and the guidelines for fatigue strength assessment which
define the requirements for fatigue strength evaluation for stress-concentrated
parts.

ClassNK added that the main components include design loads
dominant for hull structure, strength analysis methods and corrosion
deductions, design scenarios in which assessments are required by the IMO IGC
Code, local strength requirements for inner hull structures, and strain control
requirements for inner hull structures required by designers of membrane cargo
containment systems.

According to the company, a calculation function
corresponding to the requirements of the guidelines will also be added to the PrimeShip-Hull
series, the society’s hull structure design support software.