ClassNK releases new Car carrier structure guidelines
Japanese Classification Society ClassNK has released its latest Guidelines for Vehicles Carrier Structures to address the new designs of ships that are entering the sector. The Guidelines specify the technical requirements specifically related to the structural strength assessments of vehicles carriers by using direct calculation.
Vehicles carriers are designed with a minimum number of transverse bulkheads and partial bulkheads in order to increase cargo handling efficiency as well as to permit more vehicles to be loaded on board; this, however, means that the structures of such ships are fairly susceptible to racking deformation. In recent years, new types of vehicles carriers have been entering service in increasing numbers, including post-panamax and bulkhead-free designs. In consideration of such circumstances, ClassNK released its Guidelines for Racking Strength Assessment of Vehicles Carriers—Guidelines for Evaluation of Yielding Strength— in November 2016 in order to clarify unified evaluation procedures for vehicles carriers with various structural design types. As its next step, ClassNK has decided to develop its own set of technical requirements related to strength assessments for bottom structures and fatigue strength assessments due to racking deformation.
As the development of technology requirements for strength assessments has completed, ClassNK has included the latest knowledge acquired through R&D into the guidelines and renamed them as Guidelines for Vehicles Carrier Structures. The guidelines consist of “Guidelines for Direct Strength Analysis” which specify requirements related to the use of direct strength analysis to evaluate the structural arrangements and scantlings of the primary structural members of bottom structures in cargo hold areas, as well as “Guidelines for Racking Strength Assessment—Evaluation of Yielding Strength—” which outline requirements related to the use of direct strength analysis to evaluate the structural arrangements and scantlings of primary support members that support racking deformation in cargo hold areas.
ClassNK is carrying out research on the requirements for fatigue strength assessments of racking deformation and will update the guidelines upon completion.