Realistic result?

[sushi75]

Hi everyone!

I'm a bit puzzled about a simple case dealing with bar elements.
According to the theory, this type of element only works in traction-compression.

So if we consider a simple bar, 2 nodes, one constrained and the other one vertically loaded (y axis), then the solution is as follows:

-displacement along the x axis
-constraint force in node 1 along x axis

It doesn't seem very realistic to me as the load is in the perpendicular direction, however this is in line with the bar theory. So I'm a bit confused about the validity of it now!

Any clarification would be more than welcome!!

Thanks a lot :-D

 

[rb1957]

"According to the theory" according to what theory does a BAR work only in "traction-compression" ?

or do you mean ROD ?

if you mean ROD, then it won't react a transverse load. if you model your example, the model will just sit in the corner and have a nervous break-down.

another day in paradise, or is paradise one day closer ?

 

[btrueblood]

Or more likely, the solver will throw errors regarding unrestrained degrees of freedom.

 

[Kwan]

I think RB said the same thing:

(the model will just sit in the corner and have a nervous break-down) = (the solver will throw errors regarding unrestrained degrees of freedom)

This made me laugh!! I've sent models to the corner many times!

 

[bd96]

"the model will just sit in the corner and have a nervous break-down."

Haha, I laughed at that one too. I think anyone that's spent a decent amount of time making FEA models has seen his model sit in the corner on a few occasions. I've even had models that refused to ever come back out of the corner, and I had to start all over again!

 

[stressebookllc]

A bar element is fully capable, the only difference between bar and beam element for example is that the bar element is not capable of accounting for the shear center effect. Read this for more:

http://www.stressebook.com/beam-and-bar-elements/

http://www.stressebook.com/beam-bar-elements-shear-center-effect/

The rod element is only capable of providing torsional and axial stiffness (DOF 1,2,3,4).

http://www.stressebook.com

Stressing Stresslessly!