Identification of backbone curves of nonlinear systems from resonance decay responses

AbstractBackbone curves can offer valuable insight into the behaviour of nonlinear systems along with significant information about any coupling between the underlying linear modes in their response. This paper presents a technique for the extraction of backbone curves of lightly damped nonlinear systems that is well suited for the experimental investigation of structures exhibiting nonlinear behaviour. The approach is based on estimations of the instantaneous frequency and the envelope amplitude of a decaying response following a tuned steady-state oscillation of the system. Results obtained from simulations and experiments demonstrate that the proposed procedure is capable of achieving an accurate estimation of the backbone curves and damping ratios of the system provided that the premise of damping having low impact on its oscillation frequency is met

Sviluppo di una metodologia di valutazione strutturale di ponti ferroviari

Obiettivo del presente articolo è quello di fornire una metodologia di valutazione strutturale dei ponti ferroviari al fine di stabilire un attento programma di manutenzione e di definire eventuali strategie di intervento sull’opera. Tale metodologia è applicata al ponte FS Sperone della Ferrovia Circumvesuviana, situato a Napoli sulla tratta Napoli-Ottaviano-Sarno. Lo sviluppo dapprima di un modello analitico monodimensionale e poi di un modello numerico tridimensionale, nonché il confronto con un’accurata analisi sperimentale, hanno consentito di trarre importanti informazioni sul comportamento statico e dinamico del ponte, di valutarne le condizioni e di definire un attendibile e validato modello strutturale al fine di verificarne le capacità prestazionali in vista della messa in esercizio di nuovi treni con un aumento della velocità di percorrenza

Innovative Technologies for Reducing Structural Vibrations due to Natural Events and Human Activities

The need for effective structural control systems able to improve the performance of new and existing structures against service and extreme loads is ever growing. Indeed, over the last few decades the reduction of unwanted dynamics became a field at which intense research effort has been devoted and significant developments have been achieved by major research groups worldwide. This special issue aims at networking novel researches concerning complex and edge-technology systems and methodologies addressed to vibration control of civil structures subjected to natural actions as well as to dynamic loading induced by human activitie