Select Mesh
Edit from the main menu bar to merge nodes. If you select only two nodes to merge, Abaqus/CAE creates a new node at the midpoint of the selected nodes. If you select more than two nodes, you can specify the maximum distance between nodes, and Abaqus/CAE will merge nodes that are closer than the specified distance. You can also choose to remove duplicate elements that have the same connectivity.
To merge nodes:
Enter the Mesh module.
From the Object field in the context bar, select Part, and select a part from the list. This tool is available only for working on parts that contain either orphan mesh nodes or nodes created using the bottom-up meshing procedure.
From the main menu bar, select MeshEdit.
Abaqus/CAE displays the Edit Mesh dialog box.
Tip:
You can also display the Edit Mesh dialog box using the 
tool, located at the bottom of the Mesh module toolbox.
In the dialog box, do the following:
In the Category field, select Node.
From the Method list, select Merge.
From the prompt area, choose the selection method and select the nodes to merge. For more information, see “Selecting the nodes to edit,” Section 64.5.10.
Tip: You can use the Selection toolbar to change the picking behavior. For more information, see Chapter 6, “Selecting objects within the viewport.”
If you selected only two nodes to merge, Abaqus/CAE creates a new node at the midpoint of the selected nodes.
If you selected more than two nodes to merge, do the following:
In the prompt area, enter the Node merging tolerance to specify the maximum distance between nodes that you want to merge.
If the value that you entered for the Node merging tolerance is too large, Abaqus/CAE may detect duplicate nodes from the same element. Abaqus/CAE will not merge nodes from the same element, but the large tolerance can result in a distorted mesh. If the Node merging tolerance is too large, Abaqus/CAE asks if you want to continue merging the selected nodes.
Click Yes to continue.
Click No to cancel the merging procedure.
Abaqus/CAE highlights in magenta any nodes that will be merged and asks if you wish to proceed.
Click Yes to continue.
Click No to cancel the merging procedure.
Abaqus/CAE merges the nodes that are closer than the specified distance and replaces them with a single new node. The location of the new node is the average position of the group of nodes that were merged into the new node.
You can also merge part instances in the Assembly module. For more information, see “Performing Boolean operations on part instances,” Section 13.7.
If you previously created node or element sets that include nodes or elements that are deleted by the merge operation, Abaqus/CAE updates your sets accordingly.
Tip: If you make a mistake while merging nodes, click Undo in the Edit Mesh dialog box to undo the merge. Abaqus/CAE restores the nodes as they were before the merge.
Repeat the above steps as often as necessary to merge additional nodes.
When you have finished merging nodes, click mouse button 2 or the cancel button 
in the prompt area to exit the procedure.
