Model updating strategy for structures with localised nonlinearities using frequency response measurements

• Published in: Mechanical systems and signal processing Vol. 100; pp. 940 - 961
• Main Authors: Wang, Xing, Hill, Thomas L., Neild, Simon A., Shaw, Alexander D., Haddad Khodaparast, Hamed, Friswell, Michael I.
• Format: Journal Article
• Language: English
• Published: Berlin Elsevier Ltd 01-02-2018; Elsevier BV
• Subjects: Damping; Finite element analysis; Finite element method; Frequency response; Frequency response measurement; Harmonic response; Localised nonlinearities; Mathematical models; Model updating; Nonlinear model updating; Strategy; Localised nonlinearities; Nonlinear model updating; Frequency response measurement
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2017.08.004

•The strategy relies on data acquired using sinusoidal excitation, an established testing procedure in the aerospace industry.•A novel semi-analytical output residual is presented.•Amplitude-varying force input data can be used for this nonlinear model updating strategy.
This paper proposes a model updating strategy for localised nonlinear structures. It utilises an initial finite-element (FE) model of the structure and primary harmonic response data taken from low and high amplitude excitations. The underlying linear part of the FE model is first updated using low-amplitude test data with established techniques. Then, using this linear FE model, the nonlinear elements are localised, characterised, and quantified with primary harmonic response data measured under stepped-sine or swept-sine excitations. Finally, the resulting model is validated by comparing the analytical predictions with both the measured responses used in the updating and with additional test data. The proposed strategy is applied to a clamped beam with a nonlinear mechanism and good agreements between the analytical predictions and measured responses are achieved. Discussions on issues of damping estimation and dealing with data from amplitude-varying force input in the updating process are also provided.