Notation

Symbol	Definition
$t$	Time
$T$	Period
$\mathbf{M}$	Mass matrix
$\mathbf{Μ}_{e}$	Element mass matrix
$\mathbf{K}$	Stiffness matrix
$\mathbf{Κ}_{e}$	Element stiffness matrix
$\mathbf{K}_{g}$	Geometric stiffness
$\mathbf{K}_{g,e}$	Element geometric stiffness
$\mathbf{C}$	Damping matrix
$\mathbf{u}$	Displacement vector
$\mathbf{a}$	Acceleration vector
$\phi$	Mode shape
$\lambda$	Eigenvalue or buckling load factor
$\mathbf{\Lambda}$	Diagonal eigenvalue matrix
$\widetilde{m}$	Modal mass
$\widetilde{k}$	Modal stiffness
${\widetilde{k}}_{g}$	Modal geometric stiffness
$f,\mathbf{f}$	Force or force vector
$f$	Frequency
$\omega$	Angular frequency
$\Gamma$	Participation factor
$\mu$	Effective mass
$a$	Dynamic amplification
$\alpha,\beta$	Rayleigh damping coefficients
$\xi, \zeta$	Damping ratio

In general:

• scalar quantities are denoted by italics – e.g. mass $m$ or mass $M$

• vector quantities are denoted by lower case upright characters – e.g. displacements $\mathbf{u}$

• matrix quantities are denoted by upper case, upright characters – e.g. stiffness $\mathbf{K}$