COMSOL example model results do not match with Mathematical Model

Click For Summary
The discussion highlights a discrepancy between resonance frequencies obtained from a COMSOL example model for a cantilever beam and those calculated using Euler beam theory. The COMSOL model yields six resonance frequencies, with significant differences appearing after the second frequency compared to the theoretical values. Users are prompted to consider the boundary conditions defined in the model, as these may impact the results. The inquiry suggests a need for clarification on the model setup and its appropriateness for the intended analysis. Understanding these factors is crucial for accurate frequency response analysis in structural mechanics.
Oscar6330
Messages
28
Reaction score
0
Hi! I started to look into freq response analysis of a cantilever beam using COMSOL. Luckily COMSOL already has an example model "Model Library>> Structural mechanics module>>Dynamics and Vibrations>>rotating blade". While not changing anything in the model and with Omega=0 and Cloris =0, I get the following results

Resonance Freq1 = 84.36
Resonance Freq2 =528.84
Resonance Freq3 =949.31

Resonance Freq4 =1316.00
Resonance Freq5 =1481.41
Resonance Freq6 =2882.00

But Euler beam theory (options>>constants) gives me the following

Resonance Freq1 = 84.36
Resonance Freq2 =528.66
Resonance Freq3 =1862.89

Resonance Freq4 =3650.55
Resonance Freq5 =6034.61
Resonance Freq6 =9064.89

Clearly the results do not match after 2nd natural/ resonance freq. I am quite sure that COMSOL example model cannot be wrong but there is something odd. Some elaboration would be appreciated
 
Physics news on Phys.org
You're wanting to solve a cantilever beam modal analysis, but used a rotating blade vibration analysis. How are the boundary conditions defined?
 
I do not have a good working knowledge of physics yet. I tried to piece this together but after researching this, I couldn’t figure out the correct laws of physics to combine to develop a formula to answer this question. Ex. 1 - A moving object impacts a static object at a constant velocity. Ex. 2 - A moving object impacts a static object at the same velocity but is accelerating at the moment of impact. Assuming the mass of the objects is the same and the velocity at the moment of impact...

Similar threads

  • · Replies 45 ·
2
Replies
45
Views
6K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 20 ·
Replies
20
Views
5K
  • · Replies 4 ·
Replies
4
Views
10K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K