Position Control of Shell Profile and Plane Panel Stiffener

Description

The figure above is showing a plane view with two longitudinals, one with the material pointing upwards (the red one), one pointing downwards (the black one).

In this example, the Automatic Bevel box in the Profile section of the Shell Stiffener has been given the value No. The intersection point of the mould plane of the Shell Stiffener and the hull curve in the panel plane is the same.

In the plane view two different panels have been defined. Each of them containing a stiffener abutting one of the longitudinals and a cutout for the same longitudinal.

The figure below shows two other longitudinals where the value Yes has been given in the Automatic Bevel box.

Here the automatic bevel defined in the Shell Stiffener is considered. This means that the intersection point of the mould plane of the Shell Stiffener and the hull curve in the panel plane will be modified to accept tight connection at the trace of the Shell Stiffener. When modelling plane panels, components (for example, stiffeners, cutouts) referring such a Shell Stiffener, will be adjusted to meet this modification.

When creating profile parts of these Shell Stiffeners, there are no problems with the profile size.

When creating plate parts of the Shell Stiffeners, via a control file defined by the logical name SBH_PROF_TO_PLDB, there are no problems with the profile size of the web plate when the inclination angle, seen from the mould edge of the Shell Stiffener, is positive, i.e. for the lower profile in the figure above.

However, if the connection angle, when seen from the mould edge of the Shell Stiffener, is negative, the current solution in the system will result in a too big profile part.

The first step when creating the plate part of the web of the profile is to build up the geometry in the profile plane. The upper part of the web plate is positioned at a distance, equal to the web height, away from the trace part.

Next step is to calculate the dotori angles along the trace curve of the plate and to create a guiding contour. In this step the plate part is made wider and wider. There is no problem with the material size because the plate part is cut from a bigger plate, but the final web plate part will be too big and the position of the flanges in the figure above will coincide, except for the web thickness. This means that for example, an abutting stiffener will be to wide and a cutout maybe to small.

Since the described process for converting profile parts to plate parts has been the same for a long time, some customers may have found their own workarounds to meet this problem.

Therefore this functionality is now enhanced to give the customer a possibility to have the profiles positioned as shown in the first figure. By setting the Environment Variable SBH_CHECK_PROF_TRACE to any arbitrary value, further checks will be done. If the profile to be examined fulfils the criteria to be converted to plate part according to the rules given in the file assigned to SBH_PROF_TO_PLDB, calculations of connecting components like stiffeners, brackets and cutouts will be performed according to the first figure.

Inclined plane panel stiffeners will be examined and treated in the same way as described for the shell stiffeners.

Another way, already in the system, to control the position of inclined profiles is via the Environment Variable SBH_PROFPT_ADJUST. However, automatic bevel selection via SBH_BEVEL_SETS will always be the first choice.

Benefits

Enables the user to control the position of inclined profiles, curved as well as planar.

Compatibility Constraints

None.

For More Information

Refer to also User Guide Hull Model Concept / Run Mode Control / Control on Application Level / Reference Point of Profile Section.

Affected Programs

AVEVA Marine Structural Design, AVEVA Marine Detail Design