Form: Shell Assignment - Additional Mass
Use the Shell Assignment - Additional Mass form to assign additional area mass to a shell object. Note that the additional area mass is considered by ETABS only if the mass source has been specified as being based on defined mass.
The additional area mass is applied only in the three translational degrees of freedom. If it has been specified that only lateral mass is to be considered, the additional area mass is active in the global X and Y directions only.
Select the shell objects to which additional area mass is to be assigned.
Click the Assign menu > Shell > Additional Mass command to access the Shell Assignment - Additional Mass form.
Shell Mass/Area edit box. Specify the translational mass per unit area in this edit box.
Options
Add to Existing Masses: Adds the specified area mass to the shell object. If one or more area mass assignments have already been made, this option increases the existing area mass, assuming a positive mass is being specified.
Replace Existing Masses: Replaces the currently specified area mass, if any, with the new area mass. If no assignment exists, the new assignment is still made. This is the default option.
Delete Existing Masses: Deletes any and all area mass assignments made to the selected shell object(s). When this option is selected, the value in the Shell Mass/Area edit box is ignored when the Apply button is clicked.
Note that the default option is Replace and that the program defaults to this every time the form is opened.
Click the Apply button to complete the assignment.
When the Apply button is used, the Shell Assignment - Additional Mass form will remain open until it is closed by clicking the Close button. This allows selection of another shell object(s), to which a different assignments can be made.
If only one assignment is being made to only one set of selected objects, the OK button can be used to both apply the assignment and close the form.
See Also