Learning Forum

[Dora Golubiček]

I am reaching out as I am currently working on a project involving structural analysis using ANSYS simulation software. I have conducted experimental testing on a specific masonry wall, from which I have obtained valuable modal shapes and frequencies. My objective now is to replicate the same boundary conditions in ANSYS and accurately simulate the modal shapes and frequencies based on the experimental data. I understand the importance of precise setup and conditions for a successful simulation.

[Aniket]

ok so what are your roadblocks?

-Aniket

Forum Rules & Guidelines

[Dora Golubiček]

The wall is on the first floor, on one side it is free (next to an opening) and on the other side it has a slit (so it is free also). I will attach an photo of it.

Next, I will post the  modal shapes and frequencies I have from experiments:
1. 1st mode, 28Hz

2. 2nd mode, 44Hz

3. 3rd mode, 64 Hz

4. 4th mode, 76 Hz

5. 5th mode, 95 Hz
.

On the bottom and on the top of the wall I've put springs in y direction, springs for rotation x, and springs for rotation z. Also I have constrained translations in x and z direction in all nodes on both top and bottom. Sides are left with no constraints.

The modal shapes from Ansys are similar to ones gotten from experiment, but on the 3rd, 4th and 5th modal shape I can see some diversity.

Can you advise me which springs should I add or remove to achieve the same modal shapes as in experiment? I could send you videos of modal shapes from experiment and also the txt file of my Ansys model if that would be helpful.

Thank you in advance,

Best regards

[Ashish Kumar]

Hi,

Can you share a snapshot of the actual vs analytical setup model shapes? Also, can you please share the difference between the two results for a given mode?

Regards,

Ashish Kumar

[Dora Golubiček]

1.mode (experiment, ansys)


2.mode (experiment, ansys)


3.mode (experiment, ansys)


4.mode (experiment, ansys)



Here they are.

Thank you,

Best regards

[Ashish Kumar]

Hi,

Thanks for the update. I would not say that even 1st and 2nd modes are similar (the shapes are frequencies differ - Analysis 1st frequency is ~ 32% higher). A higher frequency indicates a stiffer structure. Try calibrating your model for 1st mode - try getting the model to have a mode shape similar to the experiment. 

Also, another question when you are simulating a wall why constrain it using springs? How did you get the stiffness of the springs? Is the wall constrained using the springs during the experiment?

If you can share an image of the experimental setup then maybe it be easier for members to suggest more on the setup.

Regards,

Ashish Kumar