Stochastic subspace method for structural strain modal parameter identification

Based on relationship between strain and displacement, the stochastic state-space model of a system is established with strains and strain change rates being state variables. On the basis of the model, like the stochastic subspace method with experimental displacement modal parameter identification, the stochastic subspace method for experimental strain modal parameter identification is established. The numerical simulation experiment shows that the strain modes can be identified by the proposed method accurately. Because only output is needed in the method, it can be used in the stain modal parameter identification for the structure under ambient excitation.