Special Curved Plate Concepts

A shell plate must be developed (subject to an inverse forming operation) so that the plate part can be cut in a proper shape from a planar plate. This process is called (shell) plate development and should not be confused with shell expansion which is a process, creating a traditional expanded drawing view of the shell and shell related structures.

Shell plates are developed using a technique where the plate is cut into strips that are triangulated and rolled out independently in both directions from a neutral plane of the plate, the base plane. The intersection between the base plane and the plate is called the base line.

Two roll axes (a first and a secondary) are normally calculated for a developed plate. They indicate where the rolls should be applied in a first step of forming the plates (by rolling).

For check of the shape of a shell plate it is normal to use bending templates. These may either be physical templates (for example, made of wooden board) or they may be adjustable (and thus reusable) templates of different types.

Shell plates may be assembled to a curved panel on a berth called a jig. A jig may either consist of jig pillars (normally in a fixed pattern) or jig templates, that means, of plates fitting to the shell and arranged in parallel rows.