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What are the different expansion methods for unfolding?

  • Software:

    Autodesk Advance Steel
  • Module

    Drawings
  • Question:

    What are the different expansion methods for unfolding?
  • Type:

    Methodology
  • Difficulty:

    ***

Answer

The different expansion methods for the unfolding are available in GAM -> Settings -> Defaults. The following methods are available:

1. By table
2. By DIN
3. By inner contours
4. By outer contours
5. Pure median line

What are the different expansion methods for unfolding

1. By table:
The calculation method "By table" uses for the unfolding an internal table called "UnwindingElongation" from database AstorAddIn.mdb located in the ...User2/Data folder. It can be acessed also from GAM > Settings > Table editor > AstorCurrentAddIn. The table is used either for customer specific unfolding calculations or for thicknesses that exceed the DIN method (thickness over 20 mm).

To use the table calculation method, information is required like the material expansion with the corresponding radius and bending angle.

The known values must be entered in the six columns of the table:

What are the different expansion methods for unfolding

The table acts like a filter, while the software checks first in the line from left to right and then in the following lines from top to bottom. The existing values are test / example values and can be removed by the user.

Key: Line counter; must be unique
MaterialClass: Material class number from table "MaterialClass" in AstorBase.mdb
Thickness Plate thickness
Radius: Radius of the folding at the plate median line
Angle: Folding angle measured in RAD [An angle in RAD = angle in degreed x π / 180]
Elongation: The difference of the required expansion to the median line expansion.

Example:

What are the different expansion methods for unfolding

The 2 plates with material S235JRG2, length of 100 mm and thickness of 30 mm should be folded by 60 degrees at the outside contour with a radius of 100 mm. Field tests resulted in an expansion of 30 mm so the required expansion is set to 170 mm.
The result in the table is:

Key: e.g. 10
MaterialClass: 1 (from table MaterialClass in AstorBase.mdb for S235JRG2)
Thickness 30
Radius: 85 [ = 100 mm - 30 mm / 2]
Angle: 1,047197551 [ = 60º x π / 180º]
Elongation: - 3,5 = 170 - 173,5

2. By DIN
This method calculates the unfolding according to the German norm DIN 6935. The norm is valid for plate thicknesses up to 20 mm.

3. By Inner contours
This method unfolds according to the inner contour.

4. By outer contours
This method unfolds according to the outer contour.

5. Pure median line
This method unfolds according to the median line.