Modelling a beam with a variable inertia

[aurelie689]

Hello,
I need your help about a modelling I'v got to do in order to find the vibration modes of a beam.
I hope you can understand what I mean, I'm french and I am not really fluent in english!
The beam has an "I" shape and a variable inertia (the height and the width change). However i can only make an extrusion with a constant sketch so I can't modell my variable inertia. Which function of abaqus should I use?
Thank you in advance for your help.

Aurélie

 

[ESPcomposites]

It sounds like you are trying to use a shell or solid element? Why not use a beam element. The element will just be a line, rather than an extruded section. I believe abaqus has a native varying cross section for the beam element. If not, then you just assign different properties to the elements along the length.

Brian

http://www.espcomposites.com

 

[aurelie689]

In fact I want to use a solid element to get a better vizualisation of the harmonics of my beam. In order to make the operations easier I've chosen a shell element however I didn't find how to make a variable inertia.

 

[corus]

There would be various ways to make a variable I section. In general using shell elements would be the easier option, and still give reasonably accurate results. To make the shape, you could extrude the flange section along a path and then cut to shape using an offset defined plane to make the reference sketch. You could then extrude the web section from the centre line of the flanges, and cut to shape. Alternatively, if someone else has already drawn the shape using a CAD package, just import the shape.

Tara

http://tinyurl.com/4ydjg7m

 

[ESPcomposites]

Does the ABAQUS CAE environment support "ground up" modeling or is only "top down"?

For example, this would be relatively easy in Patran (ground up) since you just create the points (4 for each cap and web, 12 total). Then create surfaces from those points. It would take just a few minutes.

Top down is great for solids and other things, but sometimes I like the ground up approach since it can be very flexible.

Brian

http://www.espcomposites.com