Identification of Vibrating Structures

The dynamic behaviour of novel and complicated structures often needs to be investigated by system analysis and system identification, since it usually has to meet certain requirements. A priori knowledge concerning the real system is gained by system analysis and/or previous tests, and it results in a non-parametric and/or in a parametric mathematical model. The identification of system parameters, i.e. experimental system analysis, is performed using measured quantities and taking into account deterministic and stochastic errors. If results of the identification have to be compared with the results of the system analysis, and if certain error bounds are exceeded, the model has to be improved. System identification has to take into account random aspects (errors, test signals), the real dynamic behaviour (damping coupling, non-linearities) and questions concerning practical handling (including large systems, economics). A broad understanding of system identification needs as its basis an extended theory of structural vibrations and estimation (stochastic processes), and must be coupled with practical aspects including experience and validated software.