Can't make a contact (SOL700)

[Qaine]

Hello,

I am working on an impact analysis of landing gear and I wanted to ask questions. First of all im working with SOL700 type which is what i need for this analysis, explicit nonlinear. The landing gear geometry is very simple one and I imported it by using iges option. I defined materials for wheels and other part of the landing gear. Then I created a surface at the bottom of the landing gear and I created mesh for both landing gear and surface. I also created some extra stuff like, velocity for landing gear, lumped mass at the top of the landing gear, gravitational acceleration. At the end, I fixed surface elements for all directions.

But when it comes to defining a contact, I think im making a mistake here because
- Even though I assigned both surface and solid as deformable body (I select a rigid material for surface)
- Even though I tried almost all variation of contact detection like automatic, 1st to 2nd, 2nd to 1st, glued, touch.. almost everything

After I get the results of the analysis, landing gear goes through the surface like there is nothing, -sorry for my bad english but I mean- there is not contact or anything, it just goes through it. I searched a little bit on internet about this problem but I couldn't find something like my problem.

So, Im stuck here and I dont know what is wrong. It would be a big help, if somebody can help me here.

Thanks!

 

[aerostress82]

You should check Nastran Analysis Examples for the version of the Nastran you are using from MSC Sofware's website.
Then you can compare an example SOL700 Nastran file with your analysis file to trace the differences between. This should give you some guidance if nobody can comment on your problem here.

Someone might be able to comment on it if you share your Nastran analysis file.

Someone had a problem with SOL400 before here in Eng-Tips, and that problem turned out to be due to the definition of the "contact elements" in the model.
That post is here. You can read it through to see if your problem is similar to this case. As it is MSC Software Nastran in both your and his cases, the problem might also be the similar issue for you guys:

http://www.eng-tips.com/viewthread.cfm?qid=405841

Spaceship!!
Aerospace Engineer, M.Sc. / Aircraft Stress Engineer

 

[Qaine]

Hello,

I checked the link and my problem may be the same, i can't be sure about that because I don't know what is the problem. I can share my nastran analysis file but there are so many output files since im using SOL700 - it is my first time ever to use this solver- so if you name the extention of the file, I can share it here. There are some errors that I've found in these files like:
From bdf file
CASE CONTROL STATEMENTS
*dytran
SOL 700
START

TIME=9999999
CEND
TITLE = MSC.NASTRAN JOB CREATED ON 16-APR-16 AT 17:15:15
LOADSET = 1
SUBTITLE=A1.DYTR
BCONTACT = 1
SPC = 2
TLOAD = 2
TYPE(D3PLOT)=D3PLOT
TIMES(D3PLOT) = 0.0 thru end by 1.000000E-04
ENDTIME= 3.00000E-02
BEGIN BULK
1 PAGE 2

BULK DATA ENTRIES

Warning following for input line:
TLOAD1 5 6 VELO 1

*** Warning 161166 (MSC+1166)
Please be aware of the difference between MSC.Dytran
and Nastran when using a TABLED1 for loading
When the x-value goes out of range:
- Dytran : By default, uses latest value (ENDVAL)
- Nastran : Uses y=0

Warning following for input line:
TLOAD1 8 9 VELO 1

*** Warning 161166 (MSC+1166)
Please be aware of the difference between MSC.Dytran
and Nastran when using a TABLED1 for loading
When the x-value goes out of range:
- Dytran : By default, uses latest value (ENDVAL)
- Nastran : Uses y=0

From f06 file
** Warning in SOL700 translator - The following Case Control entry is not supported and will be skipped
SPCFORCES(PLOT,SORT1,REAL)=ALL

Also one of the thing that caught my eye is "BCONTACT = 1" whereas it should be =ALL in my opinion ?

One last thing, I created a solid at near of the landing gear just in case to sure about my contact is working or not. Even though there is a gravitational acceleration, it just stuck in air, not moving. Im really suspicious about my load case at this moment.

Thanks for reply

 

[Qaine]

Hello again,

I created linear elastic material for both wheel and rest of the landing gear but I think I should use elastroplastic and rubber materials based on the tutorial video on youtube about SOL 700, maybe the problem is there. What do you think ?

Thanks

 

[A-MENARD]

hello,

there is a nice tuto of this, concerning a bottle on the floor :

https://www.youtube.com/watch?v=eOIAfzJjJyo

I think that is close enough of your problem , isn't ?