each weighted by a temporal function qðtÞ, the so-called modal coordinates.
The shape functions are usually obtained using eigenfunctions of the flexible car body computed by an FE-program.
This limited set of eigenfunctions approximates the motion of the car body in the lower frequency region, but strongly localized deformations caused by the actuators cannot be accounted for.
To incorporate local deformations additional shape functions are used. In order to overcome the problem of finding correct boundary conditions, frequency response modes
(FRM) are used (instead of static modes). These will be described in more detail in Section 3.