PropertyValue
Default Short CommandLMASS
Icon1583936918701-368.png

For dynamic, vibration shape and seismic effect calculations (especially for frame structures), masses can be defined optionally as point loads or automatic conversion of load cases to mass.

1582804849244-917.pngMasses are not participants of load cases, load combinations and load groups.

Concentrated Mass

Definition steps

  1. Start the 1583936918701-368.png  Mass command from 1583936924177-314.png  tabmenu.
  2. Set the mass value according to the current unit (that can be set at Settings > Units).
  3. Place the mass just by clicking in the required point.
    The mass will be displayed on the Masses object layer assigned in green color by default.

Optional steps:

  1. Modify the mass value with the 1583936958853-410.png  Properties tool of the Mass tool palette.
  2. Set the display settings of masses (Load Display Settings).

1583936991494-122.png

Figure: Definition of concentrated mass

Load Case-Mass Conversion

With the 1583937066641-337.png  Load case-mass conversion command of Loads tabmenu, you may convert load cases to masses by assigning factor values to them. All conversions are done just before dynamic calculation.

Typing 1 into the Factor field means that the loads (of the load case) with their original value will be converted to mass. Typing 0 value removes predefined conversion of a load case (as a result you will get the "--" symbol again).

1583937098727-849.png

Figure: Mass definition by conversion of loads (load cases)

The following point, line and surface force types can be converted to masses:

1583937114511-772.png  Plate module: force with global -Z direction: mz = -Fz/g

1583937119440-242.png  Wall  and 1583937129489-213.png  Plain Strain modules: force with global -Y direction: mx = my = -Fy/g

1583937124328-583.png  3D Frame and 1583937134541-127.png  3D Structure modules: force with global -Z direction: mx = my = mz = -Fz/g

1582804849244-917.pngMoments, support motions, thermal loads cannot be converted to masses.
Created by Fredrik Lagerström on 2020/04/02 17:14
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