Learning Forum

[Tian Xiang Thong]

Hi,

I am trying to compare the result of simulation with analytical solution using 2D quadrilateral element.

The result I obtain from Ansys does not match with my calculation. The vertical displacement at the top right corner based on my calculation is -0.44626 mm.

I solve the matrices using this equation:

Can someone tell me what's wrong with my calculation? Or how Ansys solve the matices? I am able to get the exact same result if I use triangular element.

Thank you.

[dlooman]

Perhaps the Ansys element is using "enhanced strain" which makes the element more flexible in bending.  If so, try turning that off and see if the displacements match.

[Tian Xiang Thong]

How can I do that?

[dlooman]

If you are using plane182, set keyopt(1) to 0:

KEYOPT(1)

Element technology:

0 -- 

Full integration with  method

1 -- 

Uniform reduced integration with hourglass control

2 -- 

Enhanced strain formulation

3 -- 

Simplified enhanced strain formulation

[Tian Xiang Thong]

Perhaps I am correct

But I still get the same result: 0.56808 mm

[dlooman]

Usually the larger deflection (less stiff model) is the more correct one.  In such a short beam shear deformation would be significant.  It would be interesting to compare solutions for a long cantilever beam.  We have patch tests in the Verification Manual so it's unlikely the Ansys solution is wrong.