The problem of structural identification has received great attention in the scientific literature. If the system to be identified presents nonlinear characteristics, then the challenge becomes particularly captivating and interesting. This is the case, for example, of the evaluation of the constitutive parameters of a prestressed beam, where any prestressing losses induce a nonlinear moment-curvature law. This work draws inspiration from [1], where the identification of the parameters of a 2 d.o.f. nonlinear mechanical system is performed through the combined use of the Hilbert Huang Transform (HHT) with the analytical technique of Complexification Averaging (CxA), starting from the processing of time-histories acquired experimentally or simulated numerically. The same technique was then implemented in [2] and extended with stochastic analyses, where the attention was shifted to a prestressed beam with prestressing losses. Here we want to verify the possibility of proceeding to the identification of the nonlinear constitutive parameters of a prestressed beam, combining the HHT with the Multiple Scale Method (MSM), in order to take advantage of the possibility of operating directly on the partial differential equations of the continuous system, thus avoiding modal projections. The final objective is to identify the constitutive parameters that simulate the piecewise linear behavior of the moment-curvature law of the beam.
This work is partially funded by the European Union - Next Generation EU, Mission 4 Component 2 Investment 1.1, in the framework of the project PRIN 2022 PNRR, “P2022ZT5X5 - Smart Under-Ground Infra-Structures for Secure Communities and Post-Disaster Emergency Response: Eco-Friendly Seismic Protection Solutions” (CUP: E53D2301762 0001, University of L’Aquila).
[1] Kerschen, G., Vakakis, A.F., Lee, Y.S., Mc Farland, D.M., Bergman, L.A., “Toward a Fundamental Understanding of the Hilbert-Huang Transform in Nonlinear Structural Dynamics”, Journal of Vibration and Control, 14(1-2), page 77-105 (2008).[2] Scozzese, F., Dall’Asta, A., “Nonlinear Response Characterization of Post-Tensioned R.C. Bridges through Hilbert–Huang Transform Analysis”, Structural Control and Health Monitoring, 24, Article ID 5960162, (2024).