# Mrt

Members

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4

## Posts posted by Mrt

1. ### using nonlinear subcase for linear buckling

at first i'll try to check units=)

i think the same, results should be similar.

linear buckling (without nnl step) results are the same.

2. ### using nonlinear subcase for linear buckling

ok=)

thank a lot.

interesting, but i have different result from abaqus. ) the rate is 2.

3. ### using nonlinear subcase for linear buckling

perfect!=)

it works!

my mistake was that i had used static nonlin-geom.)

where did you find in UsGuide part about it feature?

4. ### using nonlinear subcase for linear buckling

I've just tried to open file.

Sorry, could you resave file on HM 2017, or just send .fem file?

5. ### using nonlinear subcase for linear buckling

Wow!

Thank a lot, Guys!:)

No idea?

7. ### using nonlinear subcase for linear buckling

Hello all!

i have one question!

is it possible in Optstrct to do these thing?

i want to use nonlinear analysis (preload by weight) for linear buckling analysis/

any idea?

thank a lot, Guys!

9. ### RB2 connection between list of nodes

do you want connect "node to node"?

or "node to node set"?

10. ### Topology optimization results interpretation

are you kidding?=)

@Ekaterina needs more topics!

11. ### Topology optimization results interpretation

15 hours ago, Ekaterina said:

What is the physical difference between element densities as 0.8 instead of 1?

The penalization technique used is the “power law representation of elasticity properties,” which can be expressed for any solid 3D or 2D element as follows:
K(r) = K*ρ^p
where K and K represent the penalized and the real stiffness matrix of an element, respectively, ρ is the density and p the penalization factor which is always greater than 1.
In OptiStruct, the DISCRETE parameter corresponds to (p - 1). DISCRETE can be defined on the DOPTPRM bulk data entry. P usually takes a value between 2.0 and 4.0. For example, compared to the non-penalized formulation (which is equivalent to p=1) at ρ=0.3, p=2 reduces the stiffness of the element from 0.3 to 0.09 times the stiffness of the fully dense element. The default DISCRETE is 1.0 for shell dominant structures, and 2.0 for solids dominant structures (the dominance is defined by the proportion of number of elements)

Ekaterina and tinh like this
12. ### Optimization of a laminate with a non-symetric core

On 11/6/2018 at 1:35 AM, JFormiga14 said:

The problem is when i run i have a displacement of 1e+10 and i don't understand why

use nonlinear solver.

13. ### Cabin Thermal Simulation

28 minutes ago, nvn said:

i used on hypermesh at 2D-Mesh min/max. mesh size , but i can define by AcuSolve a global mesh size, because i have one volume, or not ? Additionally i can define curvature parameters, but my question is, is 0,02 m suitable for this model?﻿

i haven't done mesh fo cfd, i haven't ever worked in acusolve.

as for me the best way to try=) do cube, and do diffrent approach/mesh size.=)

16. ### Cabin Thermal Simulation

1 minute ago, nvn said:

which global mesh size (absolute) is suitable for this model ?

you can't use one size fo all model.

as i know you should use min/max and grow rate parameters.

and my question to @acuprowhy can't i use several volumes separated by wall?

17. ### Cabin Thermal Simulation

hello!

i am not cfd specialist.

you do great job! it's interesting issue. is it windshield defrost?

you should make 2 volumes.

first are tubes

second is cabin.

and the WALL should be common part for tube and cabin (mesh node to node).

18. ### Setting up a TIE contact

what solver do you use?

in optistruct is possible to do tie contact automatic=)

tools->contact brouser->entities field mouse right button->autocontact->property type "freeze" for tie

19. ### Internal Programming error in Optistruct

37 minutes ago, Chethan Y C said:

Current Memory (RAM)                                    :   19617 MB
(Note: MUMPS Solver Allocates Memory Separately.)
Estimated Minimum Memory (RAM) for Minimum Core Solution:   51571 MB

try to solve reduced model/part of model.
it's difficult to search mistake in large model.

20. ### Internal Programming error in Optistruct

have you tried to solve part of model? Has it gone?

maybe it's so large for your computer?

21. ### Internal Programming error in Optistruct

could you show .out file?

22. ### Internal Programming error in Optistruct

clear all previous files in work folder (close hyperview if it is opened).

check penetration.

23. ### varying SPCF for Nonlinear quasi-static analysis.

it's interesting phenomena=)

looks like scale factor 6 on OY=)

24. ### Is there any example about extracting and repairing midsurf for a complex plastic geometry?

hello, @Roy Duan!

what tool did you use?

have you ever used this feature for midmesh?

25. ### Model Reduction Methods

2 hours ago, LOKESH KATARI said:

do we have any control card for model reduction in Optistruct

=) i think so if @Prakash Pagadala say that it wasn't possible you can't do it.

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