Error in defining or computing beam section normal in 12 elements.

[VaidehiChennubhotla]

Does anyone know how to remove this error ? The model consists of wireframe(B31 elements) resting on brackets(S4R elements).
I don't know what this error means. Can anyone help ?

Error in defining or computing beam section normal in 12 elements.
The elements have been identified in element set ErrElemBeamSecNormal.

The beam cross-section direction vectors coincide at a node in 13 elements.
The elements have been identified in element set Err

 

[FEA way]

These errors refer to orientations of beam elements (those defined in the Property module using Assign --> Beam Section Orientation). You can check them both in the Visualization module (Options --> Common --> Normals --> Show normals --> On elements) and in the Property module (Tools --> Query).

Make sure that these orientations are properly defined for all beams. You can find the details in the documentation chapter "Beam element cross-section orientation".

 

[VaidehiChennubhotla]

Hi FEA way,

Thanks for the quick reply. I read the manual and checked the 'show normals' option.

t is beam element tangent vector
n1, n2 are beam section axes.

In the property module, I have identified the 12 elements by showing the element labels and the beam orientation from Tools->query. I see the t, n1, n2 vectors for each beam element. In order to remove the error that I see in the .dat file, do I have to remove these elements and recreate them with another beam orientation ? Default orientation I have used initially for the whole wire frame is (0,0,-1). Does changing it to any random orientation help me avoid these errors ? can the directions of t,n1,n2 be randomly taken ? What orientation should I choose ?

 

[FEA way]

There’s no need to delete elements. You just have to reassign the orientations. When you use the Assign Beam Orientation tool in Property module, Abaqus asks you to specify approximate n1 direction (first beam section axis) and automatically assigns the remaining local axes. Beam orientations have to be defined with care because they determine the way the beam’s section is oriented in space. Imagine a beam with rectangular or I section. In such case it’s really important how this section will be oriented.