1. Ratings

\(u\)	continuous absolute displacement field
\(K\), \({K}_{i}^{n}\)	stiffness matrix, tangent matrix
\(M\)	inertia matrix
\(R\)	vector of internal forces
\(L\)	vector second load member (linear form)
\({L}^{\mathrm{abso}}\) \({L}_{\mathrm{GR}}^{\mathrm{iner}}\), \({L}^{\mathrm{anel}}\)	second members respectively due to an absorbent border, to nonlinear inertial terms in large girder rotations, to anelastic chains (coming from control variables: temperature…)
\(\mathrm{C}\)	amortization matrix
\(Q\)	assembled deformation matrix
\({}^{t}V\)…	transposed from a \(V\) vector: dual linear form…
\(t\); \(\mathit{\Delta t}\)	time; no time
\(\alpha\)	parameter of the time integration schema of the \(\alpha\) method (and HHT)
\(\beta ,\gamma\)	NEWMARK time integration schema parameters
\(\mathrm{\Delta }\)	increment of various quantities over the time step
\(\delta\)	virtual variation of a field; increments of various magnitudes during correction iterations
\(i\); \(n\); \(j\)	time step index; NEWTON iteration index; component index
\(\mathrm{\lambda },\mathrm{\mu }\)	parameters of LAGRANGE: bond reactions, contact reactions
\(\mathrm{U},\dot{\mathrm{U}},\ddot{\mathrm{U}}\)	vector degrees of freedom of movement and successive derivatives with respect to time
\(\mathrm{P}\)	vector degrees of freedom of barotropic fluid pressure disturbances
\(\mathrm{\varphi }\)	vector degrees of freedom of barotropic fluid displacement disturbance potential
\(\mathrm{\Phi }\)	configuration: position vector: \(\mathrm{x},\mathrm{y},\mathrm{z}\) and possibly rotation vector, and other fields parameterizing the system
\(\dot{\mathrm{\Phi }}\)	time derivative of the \(\mathrm{\Phi }\) configuration with respect to time: translation speed and possibly angular speed
\(\ddot{\mathrm{\Phi }}\)	time derivative of \(\dot{\mathrm{\Phi }}\) with respect to time: translational acceleration and possibly angular acceleration
	Repeated Index Convention: \({U}_{d}^{k}\left(t\right){\mathrm{\Psi }}_{\mathrm{k}}=\sum _{k}{U}_{d}^{k}\left(t\right){\mathrm{\Psi }}_{\mathrm{k}}\)