Mass Participation Factors result

The Mass Participation Factors indicate the effective percentage of the total mass that is moving in a particular direction, for each individual mode. In any given structure, the mass participation factor is a good indicator of how susceptible a particular vibration mode is to being excited by an external stimulus. External stimuli include cyclic forces, acceleration, or displacement of the supports.

Modes with relatively high effective mass participation can be readily excited by an external stimulus. On the other hand, modes with low effective mass participation cannot be readily excited in this manner.

Following a Modal Frequency analysis, Mass Participation Factors are presented in a table, and listed separately for each of the three global directions (Participation X, Participation Y, and Participation Z), and for each mode. The total cumulative factors are listed at the bottom of the table.

Current mode only: Displays the mass participation factor results for the currently displayed mode shape and natural frequency.
Full table (all modes): Displays the mass participation factors for all calculated modes.

Note: Design standards for vibration analyses typically influence how many modes you need to calculate. Specifically, the guidelines often dictate a minimum total mass participation factor that you must achieve (such as 85% or 90%).

Important: If a model is unconstrained in one or more directions, the rigid-body translation modes in those directions result in 100% mass participation. In this case, all nonrigid-body modes show 0% mass participation in the unconstrained directions. (The reason: The maximum allowable total participation factor of 100% is achieved by the rigid-body modes alone.) Therefore, you must constrain the model for the results to indicate the susceptibility of a nonrigid-body vibration mode to excitation from an external stimulus.

Mass Participation Factors result

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