Customer Set-up of Shrinkage Factors

The experiences of shrinkage is very different between different yards. Therefore it is necessary that each customer should be allowed to control the parameters of the shrinkage used by him. This is done in a so called shrinkage (compensation) object which should be stored in the structure data bank (SB_OGDB). The name of this object can be selected freely. It must be given as an ip or default parameter in programs where the shrinkage is used, that means, mainly in modules for automatic parts generation. The shrinkage object is described in a single input language as described below and is established in a function of the hull utility inithull.

In addition to creating the object this function outputs a list of input and of explicit error messages, if any. The name of this file will be as described in the documentation of inithull.

The shrinkage object may contain at most three different types of tables:

1. The amount of shrinkage perpendicular to one weld trace of fillet type (for example, of stiffeners) as a function of the thickness of the plate against which the stiffener () is welded.

2. The amount of shrinkage perpendicular to butt welded joints (also as a function of the plate thickness).

3. Multiple tables for the longitudinal shrinkage as a function of the plate thickness. Any number of such tables may be created, each of them associated with a certain average partition (pitch) between traces.

1) + 2) will be used in the perpendicular compensation shrinkage. The most suitable of the tables of type 3) (that means, the one with the pitch closest to that of the current panel or part) will be used for the longitudinal shrinkage.

Any of the table of type 2) and 3) may be missing. In that case the corresponding contribution to the shrinkage compensation will be zero (unless explicitly given by the user in the modelling).