Modal Position#

At the output of this operator, real or complex eigenmodes are normalized to the largest of the components, which is not a LAGRANGE multiplier. To choose another standard, you must use the keyword factor NORM_MODE inside CALC_MODES, or the command NORM_MODE [U4.52.11] after CALC_MODES (we have access to more functionalities in this way).

In the case of a dynamic calculation, the data structure mode_meca_*, and mode_gene, contains, in addition to vibration frequencies and associated modal deformations, modal parameters (generalized mass, generalized stiffness, generalized stiffness, participation factor, effective mass). The definition of these parameters can be found in [R5.01.03].

In the case of a linear buckling calculation, the mode_flamb data structure contains only the critical loads and the associated deformations.

In the case of a generalized dynamic calculation with symmetric real matrices, the modal position corresponds to the position of the mode in the whole spectrum defined by the initial matrices.

In all other cases, the modal positions are assigned from 1 to Nf (Nf being the number of modes selected) by ranking them in ascending algebraic order. All modal positions are therefore positive.