Assembly meshing
Darryl,
Partition Join is available in Ideas9, under the
Cut/Join/Intersect icon stack. In Ideas8 you can find it
as a hidden command /xto/co/pj. Veyr useful for us
analysts!
regards
---- original message ----
>Manoj,
>When creating meshes on an assembly consisting of
>multiple parts, and with varying material properties,
>I prefer to create a single I-deas part. My procedure
>is to either partition the part into volumes representing
>each actual part, or more preferably take advantage of
>the new feature to "Replace Operation" to "Join
Partition".
>
>For basic partitioning, simple sketch-in-place one
>or more non-intersecting lines and select " artition"
>for the operation. However, I have seen many cases
>in which the partition operation fails, should the
>desired interface be somewhat complex, i.e. given
>a solid plate onto which a set of flanges has been
>extruded in a cross-hatched fashion. The operation
>"may" fail when attempting to partition off the
>set of flanges into a single volume (to assign a
>different material property). Also, the partition
>operation adds another feature in the history tree.
>
>Nowadays, I prefer to first Join the new feature to
>the base part, and then ctrl-m, Modify, Special
Techniques,
>Replace Operation, Join Partition, [select feature].
>This creates a partitioning surface where the new
>feature is joined. One can Join Partition newly
>created features as you go, or create all the features
>and Replace Operation, Join Partition afterwards.
>The method works for complex volume interfaces.
>
>With this approach, I have created complex assemblies
>as a single part, yet with a large number of volumes
>with complex interfaces between the volumes. This
>allows convenient assignment of material properties
>to the mesh associated with each volume, and
conforming
>meshes at the interfaces. Naturally, this approach
>assumes tight connections at the volume interfaces.
>
> erhaps I-DEAS 10 will take this one step further
>and allow one to select Join Partition during the
>initial join operation. I requested this enhancement
>via IR Number: 4660555
>
>Darryl Chong
>IBM Storage Systems
>San Jose, CA
>
>--- "McDougal, Alan" <Alan.McDougal@goodrich.com>
wrote:
>> I do about the same thing you do but I use
associative copy to bring all
>> the
>> volumes together. I come from a design
background so I'm pretty
>> comfortable
>> with AC. If you're not comfortable with it, it can be a
hard path to
>> follow. The upside is it makes everything much
more associative and, I
>> think, easier to manage for geometry changes. I
then use groups to work
>> with individual volumes.
>>
>> Unlike you however I usually model things to mean
condition and let the
>> interfaces fall where they may. I generally do
contact from there. The
>> main thing to be aware of here is that if you have
overlapping or "just
>> touch" volumes, you will need to do all you're cuts
and partitions in the
>> branches of the tree and not after the volumes have
been added.
>>
>> Alan McDougal I9m1
>> Structures Engineer HP-Unix v11.0
>>
>> Goodrich
>> e-mail: alan.mcdougal@goodrich.com
>> phone: (937)440-2031
>> fax: (937)440-3639
>>
>>
>>
>> -----Original Message-----
>> From: Dunlap [mailto:hznd58@atd.gmeds.com]
>> Sent: Tuesday, January 28, 2003 11:04 AM
>> To: keshavan@us.ibm.com
>> Cc: iccon-sim@loki.sdrc.com
>> Subject: [iccon-sim] Re: Assembly Meshing
>>
>>
>> Manoj wrote:
>>
>> >> I would like to know based on the experiences of
users what technique
>> >> they find the most convenient while building an
FE model of a complex
>> >> part.
>> >>
>> >> Specifically,
>> >>
>> >> 1.) When I build FE models of individual parts
and combine them, the
>> >> meshes are never completely aligned since the
part geometry is
>> >> complex. Hence I find myself moving nodes
around a lot. Since IDEAS
>> >> does not allow having more than one FE model
on the workbench, I can
>> >> not project the nodes from one model to the
next which would have
>> >> saved me a lot of time and trouble in meshing
>> >>
>> >> 2.) What I have been doing instead is combine
all the parts into one
>> >> giant part and create an FE model of that.
However I don't have much
>> >> control over the mesh this way.
>> >>
>> >> Is there a better way to do align meshes?
>>
>>
>> The developers of I-DEAS have made at least three
attempts to work towards
>> analyzing "systems" of multiple parts. They realize
they still have more
>> work
>> ahead of them and getting it right would be a
functional differentiater in
>> attracting new customers.
>>
>> That said, the approach I use is to "add" all the
parts into one master
>> part/Fem, leaving small gaps (say 1 mm) at the
part interfaces. I then
>> generally use the split surface command to create
matching surface
>> topography
>> and use the dependent surface command to get the
surface meshes identical
>> when
>> mesh all of the solids. I then use coupled_dofs
to "glue" the nodes at the
>>
>> interfaces together. Basically everything except for
the coupled_DOFs is
>> history supported so modifications are easy to do.
The reason for leaving
>> a
>>
>> small gap between the parts is just for convenience
so you are not working
>> with
>> coincident surfaces/nodes which makes graphical
picking more difficult.
>> Using
>> coupled_DOF's also allows you to recover the
interface forces if you are
>> looking
>> at load sharing across a complex interface (i.e.,
multiple bolts).
>>
>> Keith Dunlap
>> Allison Transmission
>> General Motors |