Display | Shape M#s | M,C,K

Displays the effective mass, damping & stiffness (also called the generalized mass, damping & stiffness) of each mode shape in the M#s spreadsheet.

Effective mass, damping & stiffness  are the values each mode would have if it were a single Mass-Spring-Damper system located at a DOF of the mode shape
This command can only be used with UMM mode shapes.

The effective mass, damping & stiffness are calculated for each mode with the formulas,

Effective Mass = 1 / (Freq x Real part (DP Residue) + Damp x Imaginary part (DP Residue)

Effective Damping = 2 x Damp x Effective Mass

Effective Stiffness = (Freq2 + Damp2) x Effective Mass


Freq - damped natural frequency of the mode.

Damp - half power point damping of the mode.

DP Residue - driving point Residue for each component of the mode shape.

The driving point Residue is calculated from each component of the UMM mode shape.