Hi Bjorn,
If you click the "Help" button on the Element Definition dialog, it should display this page from the Help: "Autodesk Algor Simulation > Setting Up and Performing the Analysis > Setting Up Part 2 >
Nonlinear > Element Types and Parameters > Line Elements > Beam Elements". (Naturally, you need to be sure that you are looking at the page in the Nonlinear section, not the linear section.)
On this page, expand the topic "Specifying the Cross-Sectional Properties of Beam Elements". This will describe the 11 input (the 12th item is the index row which cannot be changed). Then expanding the sub-section "Examples Using the General Section Type" gives an example (in Figure 8 and Table 2) showing 8 of the 11 input. The other three input would be used if any of the index strips were an arc instead of a straight section.
Let us know if you have any other questions.
John Holtz
Product Design Engineer, Algor Simulation
Autodesk, Inc.
John Holtz, P.E. Global Product Support
Autodesk, Inc. If not provided already, be sure to indicate the version of Inventor Nastran you are using!"The knowledge you seek is at knowledge.autodesk.com" - Confucius 😉