When I search for contact pairs, some parts are renamed as “Item” for some reason, despite all parts having a unique name assigned to them. So I have to look at the location of the contact and figure out which part it is.
Anyone has an idea if I’m doing something wrong or if it is just a bug? Here’s a screenshot and I’ve attached the .pmx file
CutStone1_BC_30mmXPS.pmx (1.9 MB)
The name item is used when the combined name would be longer than 35 characters.
Thanks @Matej – will keep that in mind when assigning names!
Yeah, it might be better to shorten the part names here. For example, you could have Slab1, Cladding, WallUp, Ceiling, CoreUp and so on.
Btw. this model is asking to be hex meshed by extrusion (just refine it in the thickness direction).
CutStone1_BC_30mmXPS_hex.pmx (775.1 KB)
What’s the advantage of this (I’m new to meshing)? Having looked at your model, it seems that I’d have to create a Mesh Setup for each part, which can take time if you have > 200 parts. I usually define the meshing parameters and then apply them to the whole model – is there anything wrong with this approach?
Hexahedral elements are pretty much always preferred. They give you more accuracy with way less elements.
For extruded mesh, you need separate items for each part. But if you split the parts to have subvolumes with 5/6 faces (3/4 edges each) only and create a compound part then you can use one transfinite item.
I haven’t analyzed your project in detail, so I based my opinion on a few photos. You’re gluing a lot of elements with different meshes and trying to circumvent the FEM partitioning issues with TIE constraints. Try grouping simple geometries in the model to create a “Compound.” This will maintain mesh continuity and reduce constraints.
Yes, it’s always good to replace tie constraints (leading to more computational effort and potential overconstraints) with compounding. And sometimes even better to merge the geometries in CAD software before importing to PrePoMax since compounding may not always work as expected, especially for shells. Geometry should be properly prepared before importing it to PrePoMax whose geometry editing capabilities are naturally limited to very basic operations.
In Abaqus, the Search Contact Pairs tool simply truncates the names (created using the default scheme Prefix-Contact_pair_number-Main_instance-Secondary_instance) to the limit of 38 characters because of the following rule:
Part, model, instance, set, surface, feature, and job names can have up to 80 characters; other object names can have up to 38 characters.
So you could get e.g.:
Although, as you can see, the prefix can be changed.
In Abaqus, names can’t begin with a number or underscore, so I had to remove that 0_ prefix from your part names.
Perhaps PrePoMax could use a similar scheme - remove “to”, truncate part names instead of using “item” and perhaps number pairs.
I only do compounds for objects that have a similar material – this makes it much easier to assign materials later on. Compounding objects with different material properties will make things messier. Also, I’ve tried relying on Compound only and it wasn’t returning reasonable results – almost no heat transfer.
First of all, there are some important settings in Meshing Parameters related to compound parts. One merges all compounded components into a single part object while the other results in discontinuous meshes (so that constraints are still needed, but parts are grouped). By default, multiple part objects are created and their meshes are continuous.
Compounding is very useful, but it may indeed fail for complex geometries and when there are small misalignments. Shell geometries need particularly careful preparation. That’s why it might be a good idea to merge geometries in CAD software instead.
Tie constraints are also very helpful and robust, but they have some disadvantages such as making the models more complex, causing artificial stress concentrations and overconstraints when other constraints (tie or different types) are applied to the same surfaces. There are some bugs related to them as well.
