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Inertia Relief Analysis - with SUPORT boundary conditions

Hi there

I am performing inertia relief analysis in simsolid. Looking for option how to setup SUPORT boundary conditions or virtual constraints.

How simsolid results compare when the user specify boundary conditions against other solver

I tried to solve the model with inertia relief without boundary conditions assuming the solver assumes

I have the following warning message before submitting the job for analysis

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English

SimSolid

v2022.3

Accepted answers

All comments

GirishM

Hi,

You can ignore this warning and proceed to run the solution. SimSolid will run with the inertia relief approach.

srinivas rallabandi_21059

Girish

thank you for your inputs. Before I work on my actual problem I tried on the simple part to see how close the results are wrt to other solvers

I used nastran as the solver with auto-support (param,inrel,-2) enabled where the system picks the bcs here and solved for inertia relief
I applied 100N on each mount in the vertical direction
I solved in simsolid as would like to know why there is a difference in stress. I also got few inputs from altair support where the solution settings needs to be tweaked but still the stress results are not close.
I am interested if the % error is minimal . but its not in my case
Below are my plots for your reference

Loads

Nastran Stress plot (Vonmises)

Simsolid Stress plot (Vonmises)

what are the optimum settings I need to use . How I know my optimized settings ?

I also tried custom settings as suggested , the results are not close

GirishM

Hi Srinivas,

Do you have two elements through the thickness? Are you using second order tetras in Nastran?

Can you also try to refine the result plot on the long frame in SimSolid?

srinivas rallabandi_21059

Hi Srinivas,

Do you have two elements through the thickness? Are you using second order tetras in Nastran?

Can you also try to refine the result plot on the long frame in SimSolid?

Hi girish

what do you meant by refine the result plot ?

srinivas rallabandi_21059

Do we have any verification problem in inertia relief against optistruct (inertia relief) ?

GirishM

Hi girish

what do you meant by refine the result plot ?

When you have the contour plotted, right-click on the plot to refine the result plot.

srinivas rallabandi_21059

Hi Srinivas,

Do you have two elements through the thickness? Are you using second order tetras in Nastran?

Can you also try to refine the result plot on the long frame in SimSolid?

Yes I am using second order elements in Nastran

I tried to refine the plot in the simsolid , not much difference though in the stress contour or magnitude of stress

GirishM

Yes I am using second order elements in Nastran

I tried to refine the plot in the simsolid , not much difference though in the stress contour or magnitude of stress

Can you please try to send the model to support, so someone can take a closer look and help here?