Lumped masses

This tool allows you to graphically apply lumped masses to nodes. Masses are always referenced to the global axes system. You must apply some lumped masses before a dynamic frequency analysis can be performed.

The procedure is as follows.

1. Select the nodes you wish to load, click the right mouse button and then select "Loads" => "Lumped Masses" from the popup menu that appears.
   
   OR
   
   Click the toolbar button or select "Lumped Masses - Graphical" from the Loads menu, select the nodes you wish to load, click the right mouse button and then click Ok.
   
    

2. In the load case form that appears, if you are inputting new masses then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing masses then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them.
   
   You should then choose between showing the masses applied to each selected node individually (ie. one line of data for each node) or applied as a group to all the selected nodes (ie. one line of data for all the nodes). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected nodes. This can be particularly useful if you are applying the same mass to a number of nodes. If you are inputting a different mass on each node then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what masses are already applied to the nodes you have selected.
   
   If you have elected to show the masses applied to each node individually then you can also choose between showing all the selected nodes or just the ones that are loaded. If you are inputting new masses then you would probably choose to show all the selected nodes, whereas if you are editing existing masses or just viewing masses then showing just the loaded nodes may be preferable.
   
   
   
    

3. A datasheet then appears with any existing masses shown. You can add, edit or delete masses and then click the Ok button to save any changes. The operation of the datasheet is the same as the non-graphical datasheets (see also Datasheets).
   
   
   
   Refer to "Using datasheets" for information on how to operate the above datasheet.

Note that static loads can be converted to masses using the static load to mass conversion tool in the renderer. For more information, refer to Static load to mass conversion.
 

See also Lumped mass data.