Structural Dynamics

Structural Dynamics

In the case of rigid body motion, why are all the participation factors equal to zero after the sixth mode ?

    • FAQFAQ
      Participant

      The modal participation factor is a measure of how strongly each mode shape is present in the free vibration of a structure. If the structure is unconstrained, the first six modes (the rigid body modes) fully describe the free vibration of the structure. Hence, the first six participation factors are non-zero, and all the following participation factors are equal to zero.