Mass Participation Factor
When you want to perform a linear dynamic problem (small displacement analysis with linear elastic materials), the technique used in SolidWorks Simulation is called modal analysis and requires a frequency analysis to be run first.
This inevitably requires you to choose how many natural frequencies you want to solve for (the more you include, the more accurate your solution but the longer it will take to solve). But how do you know if you have chosen sufficient modes? One useful check is to plot the Mass Participation Factors.
The Mass Participation associated with each mode represents the amount of system mass participating in that mode. Therefore, a mode with a large effective mass is usually a significant contributor to the system’s response. By plotting the Mass Participation you can see just how important each mode is.
One common rule of thumb is that a mode should be included if it contributes more than 2% of the total mass. Another is that a Cumulative Mass Participation factor of 0.8 in the predominant direction of vibration is recommended (this is found at the bottom of the list).
However as with all of these rules, some judgement has to be made and they should not always constitute the final check. For example, with dynamics it is also important to ensure that you have a suitable spatial and temporal description of your modeshapes and loading.