NLOAD1 for GRAV

Karthic_22061

Hi,

I am trying to combine the load and gravity for NLGEOM case.

I could not reference the GRAV in nload1 ? why  so 

 

But the Help states that

If a GRAV Bulk Data Entry is referenced in the EXCITEID field, the TYPE field should be set to LOAD.

 

Altair Forum User said:

cae_1_rfh,

Your initial set up was correct. You cannot use dload to combine gravity load with spc or spcd.

When you give enforced displacement within the spc itself and refer grav in the LOAD card, you are in fact combining enforced displacement and spc. This is what you have done, these results if they do not agree with your experiment/calculation etc it is perhaps due to a different discrepancy while modelling.

When you need to use nload it should be as in this attached deck

you will be creating an nload 1 for grav (you can give a time function here if necessary, using tabled1)
another nload 1 for spcd (if you are defining enforced displacement via spcd)
combine these nload 1 cards in an nload and refer this nload in the nload filed of your nlgeom loadstep

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi,

 

This is a know issue with HyperMesh. One cannot select GRAV loadcolelctors from entity editor.

 

Instead, Card edit NLOAD1 card and select GRAV loadcollector from load selector

<?xml version="1.0" encoding="UTF-8"?>

Karthic_22061

Hi Prakash,

Thank you....

 

I am trying Geom-nonlinear in Optistruct.

Please guide me in solving the Non-convergent nonlinear iterations

RADIOSS IMPLICIT STOPPED DUE TO TIMESTEP LIMIT **

      ISTOP=-2

 

I am using follower force, my aim is to estimate the force required to rotate the cam by 32 degree.while other end of the cam is pivoted(Rz free).  Please have a look at my model attached to link.

 

 

Altair Forum User

HI Karthik,

 

thank you for sharing files. I will check and update you soon 

Karthic_22061

Hi Prakash,

Any update reg- the model convergence issue

Altair Forum User

Hi Karthik,

 

I am trying with NLSTAT with LGDISP.  But the run is taking a long time to come out. 

Karthic_22061

Hi Prakash,

Is it possible to give Tabled1 load(0-100N) in NLSTAT ?

 

Is there any option to delete/remove the specified element from the model (say spring, beam) once the run have started its convergence ?

Altair Forum User

Hi karthik,

 

Using Transient non linear subcase it is possible to use table. 

Karthic_22061

Hi Prakash,

you mean Analysis type- NLSTAT with Subcase options, type - Transient non linear ?

But i don't find such a subcase option for NLSTAT.

 

Also i need to know

Is there any option to delete/remove the specified element from the model (say spring, beam) once the run have started its convergence ?

Altair Forum User

Karthik,

 

NL transient analysis is available in analysis types. 

 

Use MODCHG to activate/Deacctivate elements/ contacts during analysis. Please refer to help for more information. 

Altair Forum User

Hi Karthik,

 

The issue is with the conversion. Some entities didn't convert and this is causing problem. 

 

NL transient unfortunately doesn't support follower load. 

Karthic_22061

Hi Prakash,

Is FLLWER card must for follower force ?

Follower force is currently only supported for large-displacement nonlinear static analysis subcases ??

can i specify follower load  for NLGEOM ?

Altair Forum User

Karthik,

 

follower load is supported for NLGEOM but somehow the force component is not seen in RADIOSS;

Karthic_22061

Hi Prakash,

In NLSTAT i find option to call the FLLWER card. ( Encircled in the attached image)

But in NLGEOM i dont find the option to call the FLLWER load card ? even then will NLGEOM support follower load ?

 

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

@Karthic

 

Have you gone through this example: Nonlinear Analysis of Cantilever Beams with Follower Forces which uses follower forces in NLGEOM analysis?

 

I suspect SPCD for all the non-convergence. 

Karthic_22061

Hi Prakash,

Ya i gone through it, my run is working fine with NLSTAT.

But in NLGEOM run contact is working, but i have  Non-convergent nonlinear iterations

RADIOSS IMPLICIT STOPPED DUE TO TIMESTEP LIMIT **

      ISTOP=-2

 

Any updates from your side regarding the NLGEOM model that i shared ?

 

Thank you for the support.

 

Unable to find an attachment - read this blog

Altair Forum User

Karthik,

 

As I said earlier, there is an issue with load conversion. I cannot see the load/enforced load in the RAD files. This is happening while converting in the back ground. 

 

So did you use NLSTAT (LGDISP) with follower load?