Simulation Problems

[Anonymous]

hi,

i have been facing problems in generating a report of the modal analysis simulation. As far as i know, we need to use point masses for this particular analysis. Could u please guide me through it?

Also, my buckling analysis shows failure. I need to know what are the possible mistakes that led to this result.

Thanks a lot!

Ash 

[John_Holtz]

Hi Ash,

I will be happy to help. If I understand your message, you are having 3 problems or 3 questions.

1. You want to create a report from a modal analysis. What type of problem are you having? Is there a warning or error message? (If so, please take a screen capture of the image and attach it to your reply.)
2. You are using point masses (or want to). It sounds as if you are not sure that you should use them. The purpose of point masses is to represent the mass of something that is not included in the model. (For example, your device may include a motor attached to a frame that you are designing. Instead of modeling the motor, you add a point mass to the frame model.) Is this the type of situation that you have? Please provide some more details about what you are trying to represent and what goes wrong (if there is a problem).
3. A buckling analysis is supposed to show failure. Oh, maybe you mean the analysis did not complete. What are the details? Is there and error message in the solve details? ("Solve > Solve Details") What about in the output file? ("Results > Solver Data > Solver Output")

[Anonymous]

hi,

thx for helping 🙂 i really appreciate it.

My problems are as follows:-

1) In the modal frequency analysis, the results are the same in different load cases. For example i take 300 N for the first analysis and 500N for a separate study analysis, it gives the same results.

2) buckling analysis shows failure before getting completed. what can be the possible errors that i could be making in the setup of the analysis?

thanks a lot!

Ash

[John_Holtz]

Hi Ash,

I think that you should attach your model (or models) to a reply so that someone can look at them. Use "File > Export" to create an Archive File (.f3d). If that does not work because of the type of model, then you can follow the instructions in this article to create an archive of a model with references: How to make a local archive (back-up) file in Fusion 360

Otherwise, here are answers to your questions.

1) Modal Analysis

Are the results exactly the same or almost the same? Compare the first mode for each model (because that is where the largest difference will be seen).

• If the results are exactly the same, it may be that the load that you are applying does not change the frequency! A frequency change is created when parts are in tension or compression. A part in bending does not experience a frequency change.
• If the results are almost the same, then the load is not large enough to create a significant change in the frequency.
• Note that you may need to look at the calculated frequencies in the Solver Output text to see enough precision to know whether the calculated frequencies are exactly the same or almost the same.

Here are the types of things that need to be provided in order to understand why the results "do not change".

1. What does the model look like?
2. What are the results?
3. How much stress is created by the 300 N load?
4. Is the load creating mostly bending, compression, or tension?

2) Buckling Analysis

You have not provided any information about what the "failure" is, so it is not possible to provide any suggestions on what should be changed.

1. Is there an error message?
2. How many warnings are in the solver output? ("Results > Solver Data > Solver Output").
3. What does the model look like? What are the load and constraints?

Again, the best solution for this is to provide the model.