Working with an assembly is similar to working with a part. However, you should bear the following in mind as you work:

When you model an assembly, you are working with a nonmoving entity. Regardless of the appearance or behavior of the assembly in real-world conditions, Structure and Thermal treat all assemblies as nonmoving.

Mechanica requires that all the parts in the assembly use the same system of units. You are responsible for ensuring that all dimensioning systems in your assembly are consistent. If you use a different system of units for some of the parts, Mechanica displays a message indicating that the software automatically converts the part's units so that the units of measure are the same.

Up to the point when you run an analysis or study, Mechanica treats your assembly as a collection of individual parts. Thus, during the model development phase, you add modeling entities to parts, rather than to the assembly as a whole.

After you start a run, Mechanica merges the individual parts into a single, multivolume body, where individual parts are either connected or unconnected.

If you want Mechanica to treat your assembly as a set of shells, you must first define shells or shell pairs for each part in the assembly. You define shells and shell pairs on a part-by-part basis by accessing Mechanica after opening the individual parts.

After you have defined shells and shell pairs for each of your parts, you can access Mechanica from assembly mode and work with the assembly as a whole. For more information on shells and shell pairs, see About Shells.

If you use midsurface compression for any parts in your assembly that are made up of shells or shells and solids, gaps can form in your model where the curves (edges) or surfaces (faces) are mated or have assembly constraints applied to them. Mechanica creates connections between these gaps so the parts deform together as if they are one entity.

Although Mechanica uses shell, surface region, beam, mass, and spring definitions from the individual parts that make up an assembly, it ignores any modeling entities and idealizations you added to the parts while working in part mode. Consequently, you need to assign new modeling entities and idealizations when you work with the assembly.

Mechanica disregards all design parameters assigned to individual parts.

For assemblies, be aware that you cannot place loads or constraints on geometry that Mechanica merges during a run. If a portion of a merged surface is free—for example, two volumes that have mated surfaces, but one surface is larger than the other—you can create a surface region on the free area and then apply the load or constraint to that surface region.

When using family table instances in assemblies, note that any modeling entities you create are stored with the assembly rather than with the part.

返回pro/e文章列表>>>