FEA Strand7 model - Truss element

[Arif98]

Hi

I have this FEA Strand7 model where a truss element is oriented at 45 degree angle to the beam element.

From my knowledge I can say that truss element only takes axial stress. But the model shows that the truss element also response to bending moment when the analysis is performed.

Why is that? Is it because of the deformation of the common node in x direction causing the truss element to bend?

I have attached the model.

 

[IDS]

I ran your model and I got only axial load in the truss element, but the beam element had a bending moment at each end, which is not right.

The reason is that you selected 2D Plane for the freedom case. That restrains all rotations about the Z axis, so the "free" end of the beam acts as though it is restrained against rotation.

If you change the freedom case to 2D Beam (or just de-select restraint for Moments about the Z axis) you will find the moment at the free end goes to zero, as would be expected.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[Arif98]

Amazing! Thank you very much.

I also did an excel calculation of this structure. I was wondering why it does not match with my model. Now you helped me spotting my mistake, it all matches now.