Identification of system parameters and input force from output only

• Published in: Mechanical systems and signal processing Vol. 21; no. 5; pp. 2099 - 2111
• Main Authors: Lu, Z.R., Law, S.S.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.07.2007; Elsevier
• Subjects: Damage; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Identification; Inverse analysis; Measurement and testing methods; Physics; Regularization; Response; Sensitivity; Solid mechanics; Structural and continuum mechanics; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Response; Inverse analysis; Sensitivity; Identification; Damage; Regularization; Vibration; Length measurement; Iterative method; Simple support; Metal; Steel; Modeling; Optimization; Inverse problem; Model matching; Accelerometer; System identification; Gradient method; Damaging
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2006.11.004

A method based on sensitivity of structural responses is presented for identifying both the system parameters and the input excitation force of a structure. Both sinusoidal and impulsive forces are studied. In the inverse analysis, a short length of measurement from only one or two accelerometers is required, and an iterative gradient-based model updating method based on the dynamic response sensitivity is adopted. The location of the input force is assumed known in the identification. The poor identification with the relatively insensitive parameters in a mixture of parameters with different sensitivities is addressed and solved with another loop of optimization. Validity of the proposed method is demonstrated with two numerical simulations and verified with laboratory results from a simply supported steel beam.