You can select Tools
Virtual TopologyCombine Edges from the main menu bar to combine selected edges. During mesh generation, Abaqus/CAE treats the combined edges as a single edge and ignores any vertices that were removed.
To combine edges:
From the Object field in the context bar, select a part or the assembly.
From the main menu bar, select ToolsVirtual TopologyCombine Edges.
Tip:
You can also combine edges using the 
tool, located in the Mesh module toolbox.
Select the edges that you want to combine.
You can use a combination of drag-select, [Shift] + Click, [Ctrl] + Click, and the angle method to select more than one edge to combine. For more information, see “Selecting objects within the current viewport,” Section 6.2.
Tip: If you are unable to select the desired edge, you can use the Selection toolbar to change the selection behavior. For more information, see “Using the selection options,” Section 6.3.
Abaqus/CAE combines the selected edges. You can use the Model Tree or the Restore Entities tool to restore the selected edges. For more information on restoring individual entities, see “Restoring entities that were replaced by virtual topology,” Section 75.6.5.