desertfox, the stiffnes in PDF is 56,3021 N/mm, not 563021 N/mm.
, (comma) is the decimal mark.
How the world separates its decimals
To the right of the comma there are 4 digits, so the comma, evidently, isn't the thousands separator.
LCform, take it:
Solution of the problem with Smath Studio (free program similar to MathCAD)
Download Smath Studio
Also look at my PDF file, please.
http://files.engineering.com/getfile.aspx?folder=39712fc8-eec0-4cb3-93ac-a59a2c6a6ab9&file=Helical_spring_with__rectangular_section.pdf
