Learning Forum

[Marcos Garcia]

Hello all,

I was doing a simulation yesterday applying Inertial Relief and at night the computer was updated and erased all the information. When I got back to the office and ran the simulation again, I got an error that I cannot apply Inertial Relief in a non-linear analysis. I don't see the point since I have done several simulations of this style having nonlinear contacts with frictionless contacts and I have never had a problem. Could you tell me what could be happening? It is a model that is coupled with Frictionless and Bonded and the loads they have are the ones coming from Fluent.

Thanks in advance.

Regards,

Marcos.

[Akshay Maniyar]

Hi Marcos,

This option applies only to the linear static structural analyses. However, you mentioned that you have applied Inertia Relief in previous similar simulations that had nonlinear contacts. Can you try to compare the model setup that was running and the one you are running now and see if something has changed in the model setup? I have attached the Ansys help link for your help.

Solver Controls (ansys.com)

Thanks,

Akshay Maniyar

 

[Marcos Garcia]

Hello,

I saw that i had bonded connection only previously and about the simulation which I run yesterday now I'm not sure. 

If Inertia Relief is only for lineal analysis and not for non-lineal analysis, how I could simulate my non-lineal analysis using something similar to Inertial Relief such as making fixed the centre of gravity?

I can not share the project because it's confidential but we could suppose that I'm simulating a Drone in Static Analysis and I have frictionless contact so I can not apply the inertial relief. How could I simulate this model in Ansys Static Structural without fixed supports because my model is free of constrain in the simulation during the flight appliying the fluent pressure in this static analysis?

Thanks in advance,

Regards.

Marcos.

[Akshay Maniyar]

Hi Marcos,

Please check below forum thread below for a workaround that can be useful with the non-linear model.

How can I do non-linear analysis with inertia relief turned on on Ansys?

Thanks,

Akshay Maniyar

[Marcos Garcia]

Hi,

I have checked already but for my project it's not possible because I have a lot of components conected by beams and friction contac so I can not apply Inertial Relief to calculate the acceleration and latr turn it off with that acceleration as an input and simulate it again.

There is not possible to simulate a model in Ansys with Non-Lineal contacts without Inertial relief and using something similar with displacements?

I'm waiting your answer, 

Thanks.

[Akshay Maniyar]

Hi Marcos,

If you are using inertia relief just to satisfy equilibrium in a not fully constrained model weak springs are an alternative.  Also, a short transient analysis might provide some features similar to inertia relief, as it accounts for the inertial terms, velocities, and accelerations of the model. 

 

Thanks,

Akshay Maniyar

[Marcos Garcia]

Hello,

Thanks for the reply. Could you give me some explanation about the weak springs or give me some example to see how to do it in an assembly model?

About the transient analysis, could you provide me, if you have some paper or resoruce, any example about some plane, aircraft, drone, rocket or something similar simulated using transient analysis to see how to performance it?

Thanks!

Regards,

Marcos.

[Marcos Garcia]

Hi!

I've  already used the Weak Springs with a very low Stiffness (0.1 N/mm) and my model is working pretty good and the results are as expected.

Thanks so much.

Regards,

Marcos.

[Akshay Maniyar]

Hi Marcos,

Thats great. As your query is addressed, I will mark this thread as answered. 

Thanks,

Akshay Maniyar