How do you model Cables in Femap?

[dcxlars]

I have a structure that is reinforced by diagonal tension straps. These straps can only carry tensile loads, and buckle quickly under compressive loads. How do I model this behavior in femap w/NX Nastran? Is it even possible in a linear static 01 analysis?

 

[rb1957]

i think you can use gap elements or CBUSH elements to allow load in one direction only

 

[SAITAETGrad]

if you are doing linear static, run once and delete elements in compression...run again.

there are a few things you can do with the non-linear. There is a checkbox on the rod element property that allows it to work like a cable but only in non-linear...and then it really is just doing what is discussed in the above paragraph.

 

[ThomasH]

Hi

As mentioned gaps or cables work, but only for nonlinear analysis.

The deletion of elements might work but be very careful. When you delete an element you also change the system. That may result in the load finding another path trough the structure. You could, possibly, create a system that doesn't carry the load properly.

Good luck

/Thomas

 

[SAITAETGrad]

Thomas is correct...proceed carefully.

 

[trainguy]

For a particular load case, if a member buckles, it isn't there. If it is omitted from the model, I believe this represents reality, for that load case, with a corresponding change in load path.

The key is to remember that the member may need to be there for other load cases.

tg