Extended Shrinkage Handling

Hull has a basic function for automatic or semiautomatic compensation for shrinkage induced by heating, for example, welding. This feature has certain limitations that have been removed by the option Advanced Shrinkage handling. In the old method the amount of shrinkage compensation is evaluated considering the marking traces (the number of them, their direction and the partition between them, the plate thickness, ). But then it is always applied as resizing factors (in two directions), that means, not considering the position of each individual weld trace.

The extended shrinkage compensation is an automatic function - with options for manual overriding - that is applied in the automatic extraction of parts from the hull model, stored in nominal dimensions (both profiles and plates). Condition for the evaluation in the Advanced Shrinkage handling is that the parts have been supplied with marking traces.

Customization of the shrinkage compensation takes place via a shrinkage object that contains the amount of shrinkage as a function of plate thickness, partition between traces, This object is currently common to the basic shrinkage compensation. The condition for when a trace should be considered to contribute to the shrinkage is controlled by a large number of default parameters of the parts extracting programs.

The extended shrinkage handling has the following main features:

• Shrinkage compensation consists of two parts: shrinkage compensation

• Perpendicular to weld traces and compensation in the direction along weld traces

• The shrinkage perpendicular to the traces is applied locally in the position of the trace.

• The shrinkage compensation along the trace is applied as a scaling factor, the magnitude of which is depending on the partition between parallel traces.

• Shrinkage compensation may be applied for both planar and curved parts.

• The length of a trace relative to the size of a plate part will be considered when deciding if a trace should contribute to the shrinkage.

• The shape of a plate part will be considered: Somewhat different evaluation algorithms will be applied for "rectangular" compared to "triangular" parts.

• The shrinkage compensation in stiffeners from planar panels will be made so that the length of the profile becomes equal to the length of the corresponding weld trace on the plate (even if the trace should extend over several plates with different plate thickness).

• Additionally, it is possible to get a local shrinkage compensation at the ends of butt welded profiles.

Further detailed information about this option is available in:

Hull / Setup, customization and Standards / Shrinkage Compensation