Plate elements are unigue in another way: they have a top and bottom side with different results (due to bending). So even if you were to select a corner node (that is, a node that appears in one element only), there are two results. You can use the "Results Contours > Settings > Plate Options" to control whether the results are for both sides, the top side only, or the bottom side only.
Regardless of the settings for Smooth and the side, the CSV file still contains two rows of "Value"s for each element connected to the node. It looks to me that the values correspond to the element and side only when Smooth is turned off and both sides are shown. When Smooth is on, the same value is shown for each element. If either the top side only or bottom side only is on, then the value in the top and bottom row are the same. Make sense? Perhaps the attached images showing one node connected to 4 elements will make it easier to understand.
Excel 2010 (and maybe older versions) include a command to "Remove Duplicates", so it would be relatively easy to get rid of the extra data.
John Holtz, P.E. Global Product Support
Autodesk, Inc. If not provided, indicate the version of Inventor Nastran you are using.If the issue is related to a model, attach the model! See What files to provide when the model is needed.
