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Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

[ Edited ]
Hello!,
This is an urgent request to NX NASTRAN developpers to support 2D Axisymmetric elements CQUADX and CTRIAX to perform elastic-plastic material analyses using isotropic material + large displacements effect with the nx nastran basic nonlinear module SOL106 with the following types of yield criteria:

    von Mises (ductile materials)
    Tresca (brittle and some ductile materials)
    Drucker-Prager (sand and concrete)
    Mohr-Coulomb (rock material)
This missing capability of nonlinear elasto-plastic analysis with 2D axisymmetric elements on NX NASTRAN SOL106 should be improved urgently, this is a basic feature for any today's nonlinear solver -- thanks!!.
Best regards,
Blas.
10 REPLIES

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Blas,

This forum is not the appropriate avenue for submission of enhancement requests. Please log an IR with your local GTAC support office so that they can officially document the request in an ER. This ER will be routed to the NX Nastran Product Manager for review.

Regards,
Jim
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Dear Jim,
Thank you for taking time to answer the message. Of course, I have already filled an IR1860069 dated August 2, 2011, one week later not any answer received from GTAC.
Jim, this request is very important for the NX NASTRAN community, elasto-plastic nonlinear material model feature is critical on the application of Dessign by Analysis (DBA) in both the European Standard & ASME VIII rules to study pressure vessels where two approaches exist: the direct route using elasto-plastic calculations and the stress categorisation method.


For example in the Direct Route-check against Gross Plastic Deformation (GPD), for admissibility it is only necessary to show that (for the defined actions with appropriate safety factors) the resulting elasto-plastic stress field is an equilibrium stress field where the absolute maximum total principal strain does not exceed 5%.




The limit load has to be determined using Tresca’s yield condition with associated flow rule and first order theory. If no subroutine for Tresca’s yield condition is available or if it shows too bad convergence, Mises’ yield condition can be used instead. Since the maximum ratio of the Mises equivalent stress to the Tresca equivalent stress for the same load is 2/√3, a multiplication of the design resistance with √3/2 will always lead to conservative results.

In summary, the use of 2D axisymmetric elements is critical in the study and design of pressure vessels where rotational symmetry exist, then taking advanced of a very reduced model size instead to be forced use 3D Solid brick CHEXA 8-nodes elements.
Please make your best to convince NX NASTRAN developpers to implement this feature urgently in SOL106 -- thanks!.



Best regards,
Blas.




Blas,

This forum is not the appropriate avenue for submission of enhancement requests. Please log an IR with your local GTAC support office so that they can officially document the request in an ER. This ER will be routed to the NX Nastran Product Manager for review.

Regards,
Jim

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Blas,

We are working on improving SOL 106 capabilities - in NX Nastran 8, we added material nonlinear support (plasticity, nonlinear elasticity, and creep) in SOL 106 for parabolic CHEXA and CPENTA, as well as linear and parabolid CPYRAM elements. See the NX Nastran 8 Release Guide for details.

I'm glad you submitted an IR. I'll pass your note on to the NX Nastran product manager.

Regards,
Jim
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Dear Jim,
I am aware of the new capabilities of NX NASTRAN 8.0, just upon released I have explained new features by detail in both our blog & website (and I run NX NASTRAN 8.0 as well!!):

Finally we have the long awaited 2D plane stress/plain strain elements available in NX NASTRAN SOL101 Rev8.0, great!!, I look forward to see very soon all 2D SOLID elements fully supported in NX NASTRAN SOL106 with all material models + geometric nonlinearities -- thanks!.

Best regards,
Blas.

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Hi Blas, Jim,

 

Is there any update on this ?

 

I see from the Multi-Step Nonlinear User’s Guide that in SOL401 CQUADX4 & CQUADX8 now support nonlinear material modes.

 

I am performing an axisymmetric analysis using FEMAP and NX Nastran SOL106, and require elastic-plastic nonlinear material. When I try this with CQUADX8, I don't seem to get any plastic effect. So I guess this is not supported in SOL106 ?

 

Is there any plans to add nonlinear material (elastic-plastic) material modes to the axisymmetric elements in SOL106 ?

 

Is it possible to export an input file for SOL401 from FEMAP ? I can't find an option for this solver in Analysis Set Manager.

 

Regards

 

Fergus

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

The elements that are available for small strain material nonlinearity in SOL 106 are documented in the Basic Nonlinear Analysis User's Guide here:

 

Small Strain Elements

 

Note that there are no axisymmetric elements in this list.

 

 

SOL 401 or SOL 601,106 can be used for elasto-plastic analysis of axisymmetric elements.

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Hi Jim,

understood. But what is requested is support of _basic non linear_ axisymmetric elements in SOL 106, [not SOL 401 or SOL 601,106], as anyone would reasonably expect from a software like NX NASTRAN.

Why has our call not been reviewed? IR opened 23-nov-2010; ER opened 29-nov-2010.
Not reviewed as of 31-march-2017.

1820315 OPEN NR axisymmetric solid elements/sol106 to be supported

best Regards

Cyril
Cyril

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

As noted above, these elements are available in SOL 401 and 601,106. The noted ER dates from 2010 / NX 6 timeframe. At that time the elements were available only in SOL 601,106. A concern noted in the ER is that SOL 601 required an additional license. SOL 401 is part of the Nastran Basic license (same as SOL 106) so no additional license is required to perform an elasto-plastic axisymmetric analysis in SOL 401.

 

I've notified the product manager and asked him to review the ER.

Re: Support of Axisymmetric CQUADX elasto-plastic material model by NX NSTRAN SOL106

Dear Jim,

thank you for your answer.


I am looking for sol 401 in NX10 but I cannot locate it!


Can you please explain what combination of choices between Solver, Analysis Type and Solution Type activate this particular solution?

 

For exemple "SOL 401" does not appear with NX NASTRAN/Structural, nor NX NASTRAN/Axisymmetric Structural. If NX Multiphysics/structural is selected, there are no such Solution Type as "SOL anything".

 

 

best regards

Cyril