## General Mechanical

#### Strains in a vibrating Euler-Bernoulli beam

• MathijsvDijk
Subscriber

Hi all,

I am trying to calculate something using (among other things) the strains at specific points in a vibrating beam. My beam consist of simply supported structural steel of 1mx0.1mx0.06m.  I first did this using the standard element types, but later on realized that in my beam Euler-Bernoulli Beam theory MUST be preserved. Using any type of SOLID element i've found so far, Euler-Bernoulli isn't applied. Meaning the strains on top of my beam, differ quantitatively from the strains on the bottom of the beam.

If I mesh my beam extracting the beam from the geometry in Spaceclaim. I no longer have the option to see strains, of stresses at any points in my cross section, because the entire beam is now 1 element.

Is there any way for me to reach my goal? I've added some pictures, for you to get a better understanding of what i did. In the red square you can see the strains of two nodes (one at the bottom and one at the top) plotted. These should be equal and opposite to eachother, which is clearly not the case.

Mathijs

• MathijsvDijk
Subscriber

Hi all,

An update; I still haven't figured out this problem. I would like to use a BEAM3 element, but those are no longer supported in ANSYS 19.2. I have figured out how to get the crossectional forces in a beam element. However, in a BEAM188 element, the strains on top, and on the bottom of the beam are not the same. Meaning Euler Bernoulli is not applicable.

Is there a way to use BEAM3 elements in Ansys 19.2 workbench?

Mathijs

• peteroznewman
Subscriber

ANSYS has a BEAM4 legacy element.

• MathijsvDijk
Subscriber

Hi Peter,

Thanks for your reply. I can't get it to work though. If i force BEAM4 elements with a command snippet. It returns the following error:

Real constant set 1 undefined but referenced by element 1.

It does this for element numbers 1-21. Is there a sollution around this in workbench?