The stretch data

Stretch data describes the length variation of each plate edge after expanding, reflecting the difference between the curved edge length and the developed flat edge length. Only the double curved expansion creates stretch data, because only a double curved plate requires stretch in order to be formed. There is no stretch data for a single curved expansion. 

Therefore this stretch data is a useful measure to check if a double curved plate can be formed into the desired shape at all, before having the expansion being cut and sent to the workshop. The stretch data is used to verify the double curved hull expansion. If the amount of stretch is not within the required boundaries for a particular plate, then the seams & butts for that hull plate must be adjusted.

In MasterShip, the stretch data is displayed in a TXT-file (shown figure 2 below).

Figure 1: An example of stretch data (right)

Which SHIP-commands apply?

The stretch data is generated while using the command SHIPDOUBLECURVEDEXPANSION. After the command is done, the stretch data (in a TXT-file) is by default found in the project folder root. This location can be changed via SHIPOPTIONS > Parts Generator > Double curved expansions > Export folder.

How can the stretch data be used?

• Model verification and production design self-check: Stretch data is a useful measure to check if a double curved plate can be formed into the desired shape at all, before having the expansion being cut and sent to the workshop. If the amount of stretch is not within the required boundaries for a particular plate, then the seams & butts for that hull plate must be adjusted.
• Guidance for forming process: Professionals in the workshop can assess the needed treatment for forming the plate based on the stretch data. And they can compare the actual edge dimension of the formed plate with the theoretical curved edge of the 3D model.