You can select multiple native part instances and merge them into a single part instance. For example, Figure 13–18 shows two part instances that model a 15-pin connector. The two part instances are positioned along a common face and then merged into a single part instance that can be meshed and analyzed.

If desired, you can use the Part Copy dialog box to create a mirror image of a part about one of the three principal planes. For more information, see “Copying a part,” Section 11.5. You can merge part instances even if the instances are not touching or overlapping. You can choose whether to remove or retain the intersecting boundaries between the merged part instances, as shown in Figure 13–19.

When you merge part instances, any sets or surfaces on the original parts and part instances are mapped to the new part and part instance. If sets or surfaces from different parts have the same name, they are merged into a single set or surface on the merged part and part instance. If you choose to remove intersecting boundaries between the merged part instances, portions of sets or surfaces that lie on those boundary edges and faces are removed from the mapped sets and surfaces.

Section assignments from the original parts are also mapped to the new part. If parts in the original assembly intersect, Abaqus/CAE can map only a single section in the intersecting regions. Similarly, if parts are exactly touching or intersecting and the intersecting boundaries are removed during the merge, Abaqus/CAE maps only a single section to the entire merged part. In these intersecting situations, the section that gets mapped is dependent on a variety of factors and may not match your modeling intent. When merging intersecting regions, you should retain the intersecting boundaries; the boundaries preserve the original section assignments in nonintersecting regions and make it easier to modify mapped section assignments if necessary (for details, see “Managing section assignments,” Section 12.14.2).

You might want to merge part instances for the following reasons:

• If part instances touch or overlap but you do not merge them, Abaqus/CAE creates a separate mesh for each instance and you must apply tie constraints to effectively merge the nodes. In contrast, when you merge part instances, Abaqus/CAE creates a single combined mesh and you do not need to apply computationally expensive tie constraints. In effect, you have created a compatible mesh between the part instances. If you want to retain the concept of separate part instances, you can create partitions at the common interface of the merged instances.

• Merging part instances allows you to assign material properties to the single part created by the merge operation instead of to each part individually.

• You can apply a display body constraint to a group of merged part instances instead of applying the constraint to each part instance individually.

• When you import a complex assembly, the assembly may appear in Abaqus/CAE as a large number of individual part instances that will be meshed individually. You can merge all the part instances into a single part instance, or you can merge groups of part instances into several separate part instances.

You can select a single part instance to be cut, and then you can select one or more part instances that are touching or overlapping the part instance to be cut. Abaqus/CAE uses the part instances that will make the cut (the die) to cut away from the part instance to be cut (the blank). You cannot cut part instances that are not touching or overlapping.

When you cut a part instance, sets, surfaces, and section assignments from the original part and part instance are mapped to the new part and part instance. Portions of original sets and surfaces that lie within cut portions of the original geometry are removed from the mapped sets and surfaces.

The cut operation is useful if you want to create a mold from a part or vice versa. Figure 13–20 shows a bottle and a rectangular blank and how the cut process creates the mold.

You cannot make a cut with a shell part instance. As a result, before the cut operation was performed, the bottle was converted from a shell to a solid part in the Part module. For more information, see “Creating a solid feature from a shell,” Section 11.21.5, . In addition, the original part instances (the blank and the die) were suppressed after the cut operation. The cut operation is also useful for modeling a structure and an acoustic medium when you are performing an acoustic or shock analysis.