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Enforced Displacements in Steps

Hi

I am solving a Non Linear Static Analysis as shown in the image below.

I had fixed 2 bottom Rollers and apllied a enforced displacemnet to the top Roller using RB2 Elements.

1)My intension was to solve it in two steps 1)with 15mm displacement and 2) Removing it (so that it go backs to it initial position).I am interested in its plastic strain.I failed in achieving it.Could some help me in applying enforced displacemnt in two steps.

 

2)Then i solved it in only applying enforced displacement of 15mm in one step.Still i am not able to get the results that i obtained in other softwares.I am interested in solving it in NX Nastran.

 

Thanks 

Dinesh

 

 

8 REPLIES

Re: Enforced Displacements in Steps

Which solution are you running?

 

In general, put the load in the first subcase. Create a second subcase with no load. The results at the end of the second subcase will be the residual plastic stress/strain.

Re: Enforced Displacements in Steps

Hello Jim

Thanks for reply.

I solved it using NL 106 Multiconstraint.The reason behind using a NL Analysis was the results from a different software.As Von Mises Stress were very less i tried doing a  Linear Analysis .The results of Linear Analysis are as follows

I was expecting high stress at Box Column than at the Roller .I assigned Aluminium to Box Column and Steel to Roller.I endedup negligible stress at the Box Column.

Please let me know why i donot end up stress at the Box Column.15mm Enforced Displacement is more enought to produce high stress . I even tried with 50 mm enforced displacement.

Once i end up with fine results let me solve it 106 NL Multiconstraint.

Thanks & waiting for reply

Re: Enforced Displacements in Steps

Still not sure what solution sequence you are using. Your solution setup graphic indicates face contact being defined, but SOL 106 does not support face to face contact.

 

Your results look like no load was applied, so there are obviously issues with the solution setup.

Re: Enforced Displacements in Steps

Dear Jim

I am solving a Simple Static Structural Linear Analysis.

Please tell me how do i simualate the same using contacts .

Yes a displacement of 15 mm is applied .Is this not a load? Not enough to solve a problem.

As i said i solved the same problem applying 15mm displacement to the Roller in a different software using Frictional Contacts.It solved the same .

Now i am interested in solving it NX Nastran .Is NX Nastran not capable of solving the same using Displacement and Contacts.

Please tell which contacts to be used and what Solution Type has to be applied

Thanks.

 

Re: Enforced Displacements in Steps

hi,

solution type 101 can't simulate nonlinear;

106 can't simulate contact

may be you should try to use advanced nonlinear 601,106

Re: Enforced Displacements in Steps

Hi Jony,

Will 101 simulate the above problem linearly with contacts?

If Yes,it did not solve the above problem linearly with contacts.

If No how do you suggest me to solve for a linear case with contacts.

As of now i am not at all interested in Non Linear as i am unable to get results for a linear analysis.So there is not point in trying it in Non Linear way.

 

Thanks

Re: Enforced Displacements in Steps

Hi Jony,

601,106 is unable to write results for the problem.

Please suggest the best way of solving this problem.

Thanks

 

 

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Re: Enforced Displacements in Steps

Enforced displacements are not considered to be loads by Nastran  and do not appear in Subcases