Is there a way to convert an assembly to a single solid which then
allows the application of Cosmos Express.

I have been able to use Combine bodies IF all the parts are in
physical contact with assemblies and weldments.  However when there
are any gaps between parts then this approach does not work.

I have tried Joining Parts, Combining Solid Bodies, Converting
Assembly to a part, Exporting to STEP and Parasolid then importing
back.

Did not SolidWorks in an earlier version like 2001PLUS convert an
assembly to a dumb solid (i.e. one piece)?

Kman

If there are gaps between the components how would the FEA give any
kind of realistic answer?

TOP

On Mar 31, 1:53 pm, "TOP" <kelln...@cbd.net> wrote:
> If there are gaps between the components how would the FEA give any
> kind of realistic answer?
>
> TOP

I would be satisfied if there is a method by which these small gaps
between parts are filled and then apply Cosmos Express.  This would at
least get me in the ball park (poor man's version of Cosmos)

Would it be possible to convert an assembly to a single part (using
the surfaces only option) and then make this into a solid?  Thinking
out loud.

I thought Cosmos (full version) does analyize assemblies.  Even those
with gaps?

Kman

Make ur assembly

then while save it or saves as choose part from the file type, u can
choose either of three option i.e. 1 to have surface only, 2 all parts
and 3 outer parts and then your assembly (the saved part) will be a
single part.

Then u can check for small gaps and fill that gap with solid or
surface modeling.


Hope this works for you


Deepak

Just how many components in this assembly? Why not fill the gaps in
the assembly?

SW sometimes gets it write and sometimes not when exporting as a
part.

Here is a pretty bizarre thought.

1. In your assembly, insert part and extrude a block around the entire
assembly.
2. Use the assembly components to cut a cavity into the block
3. Use delete and patch face to remove the slivers
4. Take the resulting cavity and turn it into a solid by repeating
step 1 above
alt 4. In the part with the cavity make a second block identical to
the first as a second body. Then do a combine subtract operation on
the solids.

TOP

On Apr 1, 5:05 am, "Engineer" <guptasolidwo...@gmail.com> wrote:
> Make ur assembly
>
> then while save it or saves as choose part from the file type, u can
> choose either of three option i.e. 1 to have surface only, 2 all parts
> and 3 outer parts and then your assembly (the saved part) will be a
> single part.
>
> Then u can check for small gaps and fill that gap with solid or
> surface modeling.
>
> Hope this works for you
>
> Deepak

The assembly has 86 parts of which 28 have clearances between them.
That is alot of clean up work.
Kman

On Apr 1, 6:23 am, euchre45...@mypacks.net wrote:
> On Apr 1, 5:05 am, "Engineer" <guptasolidwo...@gmail.com> wrote:
>
> > Make ur assembly
>
> > then while save it or saves as choose part from the file type, u can
> > choose either of three option i.e. 1 to have surface only, 2 all parts
> > and 3 outer parts and then your assembly (the saved part) will be a
> > single part.
>
> > Then u can check for small gaps and fill that gap with solid or
> > surface modeling.
>
> > Hope this works for you
>
> > Deepak
>
> The assembly has 86 parts of which 28 have clearances between them.
> That is alot of clean up work.
> Kman

Gotta say something about common sense engineering here.

How can you expect to get Cosmos to give you an answer when the
assembly you have does not describe reality?  You can't make a
physical assembly with gaps and have any structural integrity until
part touch and fasteners or joints take loads.

Reality must prevail.  Some rethinking of the overall structure is
needed.

Bo

On Apr 1, 11:05 am, "Bo" <b...@tilikum.com> wrote:
> On Apr 1, 6:23 am, euchre45...@mypacks.net wrote:
>
>
>
>
>
> > On Apr 1, 5:05 am, "Engineer" <guptasolidwo...@gmail.com> wrote:
>
> > > Make ur assembly
>
> > > then while save it or saves as choose part from the file type, u can
> > > choose either of three option i.e. 1 to have surface only, 2 all parts
> > > and 3 outer parts and then your assembly (the saved part) will be a
> > > single part.
>
> > > Then u can check for small gaps and fill that gap with solid or
> > > surface modeling.
>
> > > Hope this works for you
>
> > > Deepak
>
> > The assembly has 86 parts of which 28 have clearances between them.
> > That is alot of clean up work.
> > Kman
>
> Gotta say something about common sense engineering here.
>
> How can you expect to get Cosmos to give you an answer when the
> assembly you have does not describe reality?  You can't make a
> physical assembly with gaps and have any structural integrity until
> part touch and fasteners or joints take loads.
>
> Reality must prevail.  Some rethinking of the overall structure is
> needed.
>
> Bo- Hide quoted text -
>
> - Show quoted text -

I was thinking that once the assembly was converted to a joined part,
then export as a parasolid it would be solved as a single solid part
(apparently not).  I have run Cosmos Express on the parasolid and
received the following message after running the analysis: "Failed
Faces (0), Failed Surfaces (0), surface mesh successful, volume mesh
failed, try the following -reduce element size (<12.551mm)

Whatever that message means.  And Cosmos Express does not graphically
display what the probelm is with the part.

Anyone know how to get Join to join all the parts in an assembly (not
just some of the parts)?

How does the full version of Cosmos handle assemblies with motion
between mating parts (i.e. clearances)?  Does it close the gaps before
performing the analysis?  And if it does, then it is not a realistic
model.

Kman

How are the different parts attached to eachother.

If they are welded, you should after saving the assembly as a 3d-part
(not surfaces, or use the guide which TOP described), Extrude the
weldments.

Your best opportunity is to make the model as close to the final
product.

Also Cosmos (both express and the full version) have some difficulties
if you use thin-plate elements on big parts, the minimum thinkness
compared to the total size.


Would like some more info on the what it is you are making, and what
you need the Cosmos Express calculation for (deflection? stress
analyses?).

You should keep in mind that there are a lot of things that can go
wrong using Cosmos Express. Do you have any experience using FEM ?

About how the full version of Cosmos works, it builds elements just
like the express version, you just have a whole lot of options on how
these elements are build, where the Express version comes with a
standard set of options.

In both cases the program wont make anything up, it is analysing what
you have made. Which means you have to put in bolts or weldments if
thats the way its assemblied, if you want the right result.

If you want to "cheat" and do less work, simplify the area you want to
analyse. You should have a good idea on where the problems would accur
already (if you dont, then the Express version is a "no go" anyways).

So issolate the place where you think the worst stresses / deflection
are and constrain it in a proper way getting it as close to reality as
possible. This would give you a better result than running the express
version on the whole model, cause you are controlling more of the
unknows.

Even with the full version, its a lot of work getting the elements
build in a proper way and making sure they are connected in the right
way also.

On Apr 2, 4:42 am, "Ronni" <r...@tresu.dk> wrote:
> How are the different parts attached to eachother.
>

The assembly is an equalizing roll clamp and tensioning mechanism.
Lift consists of RH-LH core clamp, each of the core clamp sub-
assemblies slide independently on a common pair of guide shafts, the
roll core cones RH-LH rotate independently.

> If they are welded, you should after saving the assembly as a 3d-part
> (not surfaces, or use the guide which TOP described), Extrude the
> weldments.
>
> Your best opportunity is to make the model as close to the final
> product.
>
> Also Cosmos (both express and the full version) have some difficulties
> if you use thin-plate elements on big parts, the minimum thinkness
> compared to the total size.
>
> Would like some more info on the what it is you are making, and what
> you need the Cosmos Express calculation for (deflection? stress
> analyses?).
>

Interested in both deflection and stress analysis.  Areas of interest
are the deflection/twist/stress of the guide rods supporting the RH-LH
roll clamp sub-assemblies.  Twisting of thte RH-LH clamp sub-assembly
side plates (load is cantileverd off the side plates).


> You should keep in mind that there are a lot of things that can go
> wrong using Cosmos Express. Do you have any experience using FEM ?

FEM? none

On Apr 2, 5:10 am, "Ronni" <r...@tresu.dk> wrote:
> About how the full version of Cosmos works, it builds elements just
> like the express version, you just have a whole lot of options on how
> these elements are build, where the Express version comes with a
> standard set of options.

Purchasing full version is not an option.

>
> In both cases the program wont make anything up, it is analysing what
> you have made. Which means you have to put in bolts or weldments if
> thats the way its assemblied, if you want the right result.

What about clearances between bearings, slides etc... (the way it is
assembled)
How does Cosmos handle component clearances?  If I understand you
correctly, it does not.  That would mean in order to do an analysis
one would have to make a new assembly just for this purpose.  We are a
small company and do not have the resources or time to develop mock
assemblies for the purpose of analysis.

I recall a time when we hired an engineer with FEA background via one
of our VARS to calculate the deflection of a machine base section for
an automotive transfer and assembly line.  The deflection results were
off by 100%.  We paid alot of money for that one simulation and the
results were useless.  The engineer was provided the actual model and
loading conditions.

Simplification: One method being, calculate a beam of equivalent
inertia for each RH-LH sub-assembly, attach the beam to the guide rods
and run a simulation.  It is unfortunate SolidWorks/Cosmos can't close
the gaps to make a solid of the assembly.  This result would be much
more accurate and take considerable less time.

>
> If you want to "cheat" and do less work, simplify the area you want to
> analyse. You should have a good idea on where the problems would accur
> already (if you dont, then the Express version is a "no go" anyways).

Simplifying and using beam calculations is reasonable for some of the
components.  Determining the multitude of deflections and stress on
the guide shafts is not so straight forward.  The load on the roll
cones RH-LH is both cantilevered and eccentric.  Ideally, the loads
are symmetrical on both side.

>
> So issolate the place where you think the worst stresses / deflection
> are and constrain it in a proper way getting it as close to reality as
> possible. This would give you a better result than running the express
> version on the whole model, cause you are controlling more of the
> unknows.

I would think the results will be less accurate.  When you say
"controlling more of the unknowns", to me, means making assumptions to
simplifying the model.  I really would have preferred Cosmos Express
(for parts) to simulate an assembly.  If SolidWorks JOIN command
worked as marketed then this may have been possible.  Or maybe, the
complexity is still too much for Cosmos to simulate as previously
mentioned.

>
> Even with the full version, its a lot of work getting the elements
> build in a proper way and making sure they are connected in the right
> way also.

That is disappointing  news.  The Cosmos (full version) demonstration
I witnessed a couple years back didn't mention any shortcommings,
grin.

This is a reasonable request.  Structural steel fabricators CANNOT have 
steel on steel (0" gap).  I allow 1/16" per side when fitting up to 
structural members.  This works great for guys in the shop, but sucks for me 
if I want to do any type of analysis with any FEA package.  My only solution 
is to create a variable with the gap distance and factor that in to the 
length of that part, then I can use configurations to vary that gap number, 
then turn it on shop drawings parts and assemblies or turn off for FEA.  Not 
clean, but the best I could think of.

Keith

<euchre45887@mypacks.net> wrote in message 
news:1175356890.255871.292510@p15g2000hsd.googlegroups.com...
> Is there a way to convert an assembly to a single solid which then
> allows the application of Cosmos Express.
>
> I have been able to use Combine bodies IF all the parts are in
> physical contact with assemblies and weldments.  However when there
> are any gaps between parts then this approach does not work.
>
> I have tried Joining Parts, Combining Solid Bodies, Converting
> Assembly to a part, Exporting to STEP and Parasolid then importing
> back.
>
> Did not SolidWorks in an earlier version like 2001PLUS convert an
> assembly to a dumb solid (i.e. one piece)?
>
> Kman
> 

<euchre45887@mypacks.net> wrote in message 
news:1175518674.388209.81420@l77g2000hsb.googlegroups.com...
> What about clearances between bearings, slides etc... (the way it is
> assembled)
> How does Cosmos handle component clearances?  If I understand you
> correctly, it does not.  That would mean in order to do an analysis
> one would have to make a new assembly just for this purpose.  We are a
> small company and do not have the resources or time to develop mock
> assemblies for the purpose of analysis.

I don't use Cosmos, but I'm sure that Cosmos works the same as Ansys. You 
have to put in contact pairs at every clearance between components that you 
expect to touch. The system applies the loads and restraints that you want, 
and then works out when and how the parts contact one another. This makes 
the analysis non-linear and usually makes it take much longer to solve, if 
it solves at all.

If your loads aren't too high, you might be able to get away with building a 
version of your assembly with the parts rotated and moved into the 
approximate positions that they will take when you apply your loads. You can 
then bond the parts together and try an analysis. If you are lucky, make 
good assumptions, and things behave well, the results won't be too far off. 
But if any of your assumptions are incorrect or your loads are high enough 
to cause the parts in contact to deflect appreciably, you will get 
essentially meaningless results.

> I recall a time when we hired an engineer with FEA background via one
> of our VARS to calculate the deflection of a machine base section for
> an automotive transfer and assembly line.  The deflection results were
> off by 100%.  We paid alot of money for that one simulation and the
> results were useless.  The engineer was provided the actual model and
> loading conditions.

You will probably be lucky to get that close.


Jerry Steiger
Tripod Data Systems
"take the garbage out, dear" 

On Apr 2, 9:06 am, "Keith Streich" <kstre...@execpc.com> wrote:
> This is a reasonable request.  Structural steel fabricators CANNOT have
> steel on steel (0" gap).  I allow 1/16" per side when fitting up to
> structural members.  This works great for guys in the shop, but sucks for me
> if I want to do any type of analysis with any FEA package.  My only solution
> is to create a variable with the gap distance and factor that in to the
> length of that part, then I can use configurations to vary that gap number,
> then turn it on shop drawings parts and assemblies or turn off for FEA.  Not
> clean, but the best I could think of.
>
> Keith
>

I hear ya.  Like many others we download commercial parts from OEM's
and distributors whenever possible.  And we get what they give us so
to speak.  Configurations seems to be the best of both realities for
now.  Thanks everyone for your input!

Kman



> <euchre45...@mypacks.net> wrote in message
>
> news:1175356890.255871.292510@p15g2000hsd.googlegroups.com...
>
>
>
> > Is there a way to convert an assembly to a single solid which then
> > allows the application of Cosmos Express.
>
> > I have been able to use Combine bodies IF all the parts are in
> > physical contact with assemblies and weldments.  However when there
> > are any gaps between parts then this approach does not work.
>
> > I have tried Joining Parts, Combining Solid Bodies, Converting
> > Assembly to a part, Exporting to STEP and Parasolid then importing
> > back.
>
> > Did not SolidWorks in an earlier version like 2001PLUS convert an
> > assembly to a dumb solid (i.e. one piece)?
>
> > Kman- Hide quoted text -
>
> - Show quoted text -

On Apr 2, 7:16 pm, "Jerry Steiger" <jer...@tdsway.garbage.com> wrote:
> <euchre45...@mypacks.net> wrote in message
>
> news:1175518674.388209.81420@l77g2000hsb.googlegroups.com...
>
> > What about clearances between bearings, slides etc... (the way it is
> > assembled)
> > How does Cosmos handle component clearances?  If I understand you
> > correctly, it does not.  That would mean in order to do an analysis
> > one would have to make a new assembly just for this purpose.  We are a
> > small company and do not have the resources or time to develop mock
> > assemblies for the purpose of analysis.
>
> I don't use Cosmos, but I'm sure that Cosmos works the same as Ansys. You
> have to put in contact pairs at every clearance between components that you
> expect to touch. The system applies the loads and restraints that you want,
> and then works out when and how the parts contact one another. This makes
> the analysis non-linear and usually makes it take much longer to solve, if
> it solves at all.
>
> If your loads aren't too high, you might be able to get away with building a
> version of your assembly with the parts rotated and moved into the
> approximate positions that they will take when you apply your loads. You can
> then bond the parts together and try an analysis.

Bonding is one of the issues.  Join, doesn't work.  Creating a part
from assembly doesn't work.  Manually modifying an assembly as you
also mention seems to be the only way this can be accomplished.

> If you are lucky, make
> good assumptions, and things behave well, the results won't be too far off.
> But if any of your assumptions are incorrect or your loads are high enough
> to cause the parts in contact to deflect appreciably, you will get
> essentially meaningless results.
>
> > I recall a time when we hired an engineer with FEA background via one
> > of our VARS to calculate the deflection of a machine base section for
> > an automotive transfer and assembly line.  The deflection results were
> > off by 100%.  We paid alot of money for that one simulation and the
> > results were useless.  The engineer was provided the actual model and
> > loading conditions.
>
> You will probably be lucky to get that close.
>
> Jerry Steiger
> Tripod Data Systems
> "take the garbage out, dear"

In my expirience when it comes to assemblies, remaking it as a part is
much faster than adjusting the assembly (making cuts and weldments).
I always make another model to make the FE analysis on.

It is a lot of work with assemblies with more than a few parts. But
the program aint better than the data you put into it, and there is no
such things as Yoda-fields :-)

So you would have to make the weldments / bolt-connections or however
it is kept together.


If you save your assembly as a jpeg and send it to me, I might be able
to have a look and give some pointers on how to rebuild as a part.

Also I need to know exactly what result you are after. Max
Deflection / von Mises stresses in a particular place. If the material
stays with the plastic deformation area, if you only allow a certain
deflection basicly what you need the result for.

Ronni,

Unfortunately, I am not at liberty to share this information.  I do
appreciate your offer to help with this problem.

Regards,
Kman


On Apr 4, 1:45 am, "Ronni" <r...@tresu.dk> wrote:
> In my expirience when it comes to assemblies, remaking it as a part is
> much faster than adjusting the assembly (making cuts and weldments).
> I always make another model to make the FE analysis on.
>
> It is a lot of work with assemblies with more than a few parts. But
> the program aint better than the data you put into it, and there is no
> such things as Yoda-fields :-)
>
> So you would have to make the weldments / bolt-connections or however
> it is kept together.
>
> If you save your assembly as a jpeg and send it to me, I might be able
> to have a look and give some pointers on how to rebuild as a part.
>
> Also I need to know exactly what result you are after. Max
> Deflection / von Mises stresses in a particular place. If the material
> stays with the plastic deformation area, if you only allow a certain
> deflection basicly what you need the result for.