Plane stress tensile testing 1

[jjamali]

Hello,
I wanted to model tensile testing of a steel plate(100mm*15*2mm, plane stress condition)using COSMOS/Solidworks. I have two questions. Could you help me?
1.when I use roller/slider to fix the base of the plate and I set 1mm displacement at the other end, solver fails. So I use fixed geometry in the base. IS this B.C. the right one?
2.What type of element is suitable for plane stress state in COSMOS?
Thank you,
Jamal

 

[btrueblood]

Is this a homework problem for school?
1. Yes, but then, no. What was the failure message? Could it be related to the fact you have a 1% strain condition?
2. A plane stress element.

 

[rb1957]

1. I wonder if you initially constrained the 6 rigid body modes ? it sounds like you applied XY constraint at one node and Y at another. if so, you didn't constrain 3 modes (Z, RY, and RZ). Fixing one node (presumably the one that had XY constraint) solves these issues (so the model runs) by over constrains the model in RX (you already have RX contrained by virtue of the two Y constraints). so strictly speaking you should remove this constraint to better reflect your application. In any case, check that these constraints react very little load ... RX may be overly constrained, but if there is no load in that direction, then there shouldn't be a problem with the results.

 

[jjamali]

Thanks,
It is academic research,
1.Failure message is just "solver failed", I think it is because there is very small displacement(maybe due to rounding errors?)in the transverse direction and as there is no constraint in that direction, nothing stops plate from displacing in the transverse direction. So I use fixed geometry to solve this problem; however I think this is not the right BC.
2. Where can I find plane stress element. I don't see this option when I want to create mesh.

I also had this question:
3.Is time dependent displacement at the loading end the right method to model loading-unloading-reloading of the plate?

 

[jjamali]

@rb1957
Sorry for silly question, but in cosmos we have either fixed geometry(6DOF) of roller slider(fixed in one direction, say fixed in x direction and it can move in yz plane). I don't see any option to put limit on rotations! Could you tell me how I can do this on nodes?
Thanks

 

[rb1957]

then i guess it's a pretty limited FEA tool, if you can't select individual freedoms to constrain.

still, if the load reacted by the additional constraints is small (very, very small) then you could consider the results reasonable. "additional constraints" refers to constraints added to solve rigid body motion, as opposed to constraints you needed to reflect the real structure.

 

[drawoh]

jjamali,

We have a forum for SolidWorks: Simulation/FEA (COSMOS).

That is a more suitable place for your question.

JHG

 

[jjamali]

Thanks.
How can I make sure that few constraints and element is due to my limited version? If I go for another version of Solidworks, can I define plane stress element and fix nodes in certain direction and rotation? Or I should go for another FE software like ANSYS?

 

[jjamali]

Thanks drawoh, How can I move this thread to Simulation/FEA (COSMOS)?

 

[vpl]

jjamali

The only way I've found to move threads is to:

(1) highlight and copy (and then it helps to use the {quote NAME} {/quote} (only with square brackets) around everyone's replies to separate them out.

(2) take a screen shot and post that.

(3) bite the bullet, retype your questions, and summarize the replies you've already received.

If you do start a new thread in the Solidworks forum (which is the better place), please red flag this one.

Thanks


Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[Cockroach]

You may have modelling errors. I do this all the time without problems. There are elementry lessons like tutorial which would help you set this up, maybe you have unconstrained geometry internal to the model.

Sounds like the error is "user input misunderstanding".

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[jjamali]

at vpl: thanks for the instruction.
at Cockroach: Thanks, but I don't agree with you. Because with a roller slider we let the model to slide in that surface(the surface perpendicular to the roller/slider).

I found how to to use appropriate BC for tensile testing. I think using roller/slider constraint is not enough.
The best way to set constraints for a tesile testing is defined in the following video:

http://www.youtube.com/watch?v=P8ldxT83qCs&feature=player_embedded#at=360