DNV DNV-CP-0093 [ Active ]

This CP gives a description of the procedures and requirements related to documentation, design and type testing applicable for TA of composite drive shafts and flexible couplings.

This CP does not set the design requirements to the composite drive shafts and flexible couplings. TA is based on compliance with design requirements given in the the Society's rules and/or other regulations and standards. The CP describes how to document compliance with the requirements in order to obtain a TA certificate for the equipment. This includes, where relevant, technical requirements for how the type tests shall be performed.

This CP covers drive shafts and flexible couplings consisting of a central section(s) fabricated from a fibre reinforced thermoset plastic (FRP) which is joined at each end to a metallic flange (CMn-steel, corrosion resistant steel, titanium etc.) for connection and for load transfer to other driveline components. The central FRP section may be divided in more than one piece, the pieces being joined with or without the aid of metallic flanges. Joints may consist of adhesive bonds or mechanical connections (e.g. pinned or bolted connections) or combinations thereof.

A type approval covers the central FRP section(s) and the bonds between this section(s) and the flanges. (Metal flanges and other metallic components shall comply with the rules requirements for shafting.)

A type approval can be given for a range of shaft designs. An approved range can include:

— a range of nominal torques for shafts/couplings of similar geometrical configuration and where the variation of the capacity of the shaft/coupling is achieved by scaling the design ¹

— minor changes or variations in design details, e.g. limited variations of the number of pins, the pin diameter, pin configuration and/or laminate thickness for pinned connections, limited changes in bonded joint configurations etc.

A type approval will be given for one specified set of raw materials, one specified method of fabrication of the central section and for one specified method of bonding between central section and the flanges including choice of materials (e.g. adhesive, type of material, steel grade etc. in the flange etc.).

A DNV type approval certificate is normally limited to one manufacturer at one production site, however, other arrangements may be agreed upon with the Society.

Type tests as specified in Sec.7 shall be carried out and verified in one of the following ways:

— at a DNV laboratory

— at a recognized and independent laboratory or a laboratory accepted by the Society

— at the manufacturer’s premises in the presence of the Society's surveyor.

¹ Normally one type approval certificate would include a range of designs where the ratio of the maximum value to the minimum value of the design parameters (e.g. diameter, wall thickness etc.) is equal to 2.5.