FRP Hull Modelling

The FRP extension of the Hull application includes such additions to the system that it can be properly used to produce drawings and production information for vessels built from fiber reinforced plastics (FRP) as opposed to steel or aluminium.

The following FRP specific features can be handled:

• Treatment of inner and outer shell curves.

  For a steel ship, the hull curves normally represent the moulded surface of the ship. In drawings, it is not necessary to take the actual plate thickness into consideration, for example, the frames curves are drawn using a bold pen.

  Building ships using FRP, the thicknesses are considerable and can not be neglected. Normally, the outer (‘wet’) surface is available but the inner side of the core material might be required (for example, for templates) together with the inner laminate surface (for the shape of the inner structure).

  Therefore, the Hull application has been given the option to create a parallel surface from a given ‘mother’ surface and to handle curves from several such surfaces in drawings and other contexts.

• Separate control of ‘core’ material and surface laminate.

  In a steel ship the structures are built using a homogenous material. In vessels built with the FRP technique, each structural member is composed by a core material and a fiber coating, normally on both sides. The thickness and density of all these layers can vary, independently of each other. The application handles this situation in drawings, in calculations of weight and center of gravity, The characteristics of the laminate, used for a special vessel, is controlled by a separate table which can modified by the user. This table defines designations, densities, thicknesses, of the laminate.

• Special types of stiffenings.

  The model generation handles special types of ‘stiffeners’, used in the FRP technique. This means a generalization of the profile concept for steel hulls.

• Definition of beads at junctions between the structural elements.

  The connections between the structural members are for FRP vessels normally reinforced by fiber coated beads. The application can generate such beads, present them in drawings and calculate their addition to the weight and COG.

• Definition of edge treatments of holes.

  Larger holes in FRP structures are normally covered by a fiber coating, with a special indication in the drawings. The option allows this coating to be defined around each hole.

• FRP specific adaptation of the rules for symbolic hull drawings.

  The symbolic drawings for a FRP vessel differs from normal steel drawings in a number of respects, for example,:

• Special symbols are used to identify the combination of core material and fiber coating for all ‘plate’ surfaces.

• The symbolic drawing of ‘stiffeners’ and adjoining structures are replaced by a drawing of the actual sizes of the elements.

• Beads are drawn and symbols for their identifications can be set.

• The number of layers (curves) in the shell can be selected by the user.

Further detailed information about this option can be found in Hull / Set-up and customization / (Fiber) Reinforced Plastics.