Static clamped beam: Elmer and Analytical solutions differ
Posted: 04 Dec 2012, 20:18
Dear all,
I'm having a problem with Elmer solver:
In my real case, I have a clamp beam with a static load at the other side. The beam is an I-type with triangular holes.
I'm having results from Catia with the GPS module and I wanted to reproduce this case with Elmer.
Unfortunately, the results are completely different from my reference for the Von Misses as well as for the displacement.
As I couldn't find what was wrong, I decided to simplify my case to a simple geometry for which analytical results exists.
So I have a circular beam, not hollowed, clamp at one side and loaded perpendicularly at the other side.
It's possible to compute analytically the stresses and displacement for that case.
I could reproduce similar value from Catia+GPS, but once again, Elmer is giving completely different results.
I tried also an other solver (z88Aurora) which is also "wrong" (and with different results from Elmer).
So I'm really wondering what is wrong in my case. I was thinking of a unit issue but I did my analyses in m and mm and
results are coherent between the 2 cases.
Please find attached the files (mesh + sif) in meter and millimeter.
The Beam is 1m long (L) and 25cm Radius (R), load (F) is 1000N. Steel: Young modulus (E): 210e9Pa
I=pi*D^4/64
Stress=F*L*R/I
Displ=F*L^3/(3*E*I)
Stress Displ
Analytical 81.46e6[N/m^2] 5.2e-3[m]
Catia 74.13e6[N/m^2] 4.9e-3[m] (acceptable)
Elmer [m] 1.49e5[N/m^2] -8.3e-6[m]
Elmer [mm] 1.54e-1[N/mm^2] -8.09e-3[mm] (similar to Elmer [m])
I'm not completely sure about this last if it's necessary to convert the load from N=(kg*m/s^2) to kg*mm/s^2 but if I don't do,
I have different results. I'm also not sure the output is in N/mm^2 maybe it's kg*mm/(s^2*mm^2) Then the results are different.
Could somebody have a look to my sif (and meshes) and tell me what's wrong?
Thanks a lot
PS:I did also a Dynamic study (clamped) and modes are similar in Elmer and Catia
I'm having a problem with Elmer solver:
In my real case, I have a clamp beam with a static load at the other side. The beam is an I-type with triangular holes.
I'm having results from Catia with the GPS module and I wanted to reproduce this case with Elmer.
Unfortunately, the results are completely different from my reference for the Von Misses as well as for the displacement.
As I couldn't find what was wrong, I decided to simplify my case to a simple geometry for which analytical results exists.
So I have a circular beam, not hollowed, clamp at one side and loaded perpendicularly at the other side.
It's possible to compute analytically the stresses and displacement for that case.
I could reproduce similar value from Catia+GPS, but once again, Elmer is giving completely different results.
I tried also an other solver (z88Aurora) which is also "wrong" (and with different results from Elmer).
So I'm really wondering what is wrong in my case. I was thinking of a unit issue but I did my analyses in m and mm and
results are coherent between the 2 cases.
Please find attached the files (mesh + sif) in meter and millimeter.
The Beam is 1m long (L) and 25cm Radius (R), load (F) is 1000N. Steel: Young modulus (E): 210e9Pa
I=pi*D^4/64
Stress=F*L*R/I
Displ=F*L^3/(3*E*I)
Stress Displ
Analytical 81.46e6[N/m^2] 5.2e-3[m]
Catia 74.13e6[N/m^2] 4.9e-3[m] (acceptable)
Elmer [m] 1.49e5[N/m^2] -8.3e-6[m]
Elmer [mm] 1.54e-1[N/mm^2] -8.09e-3[mm] (similar to Elmer [m])
I'm not completely sure about this last if it's necessary to convert the load from N=(kg*m/s^2) to kg*mm/s^2 but if I don't do,
I have different results. I'm also not sure the output is in N/mm^2 maybe it's kg*mm/(s^2*mm^2) Then the results are different.
Could somebody have a look to my sif (and meshes) and tell me what's wrong?
Thanks a lot
PS:I did also a Dynamic study (clamped) and modes are similar in Elmer and Catia