Nowadays, the increase of the commercial speed of railway vehicles is a global trend and major economical investments are being devoted to expand the length of high-speed railway lines. As a consequence, many research efforts have being focused on the development of innovative solutions to allow rail vehicles to properly face the additional challenges caused by higher speeds. In this context, this thesis proposes virtual and experimental methodologies to assist the development of new suspension components to improve dynamic performance of rail vehicles. Modelling and calibration methodologies based on lumped parameters approach are proposed to simulate the response of hydraulic damper prototypes, with the aim of quantifying their influence on the vehicle performances by means of co-simulation with Multibody (MB) train models. Moreover, dedicated experimental procedures based on the Hardware-In-the-Loop (HIL) methodology are proposed. A first HIL test rig to study the lateral dynamics of a rail vehicle is proposed to test yaw damper components, and comparative analyses are performed between different yaw dampers focusing on stability performance. A second HIL test rig, simulating the vertical dynamics of a rail vehicle featuring also the first deformable modes of the car body, is also illustrated. The aforementioned methodologies are implemented to study an innovative smart passive yaw damper designed to mitigate the trade-off between high-speed stabilizing effect and low-speed steering resistance. Then, a semi-active secondary vertical damper designed to improve the ride comfort of rail vehicle is prototyped and tested by means of HIL approach to quantify its robustness and its capability to deal with unexpected failures. To further investigate the possibility of improving ride comfort of rail vehicles, a numerical investigation is proposed to illustrate the potential benefits of introducing a passive Hydraulic Interconnected Suspension (HIS) at the primary suspension stage. The analysis demonstrates that replacing primary vertical dampers with HIS can alleviate the trade-off between ride comfort and running safety performances of high-speed rail vehicles.
Al giorno d'oggi, l'aumento della velocità commerciale dei veicoli ferroviari è una tendenza globale, e ingenti investimenti economici sono riservati all'espansione della lunghezza delle linee ferroviarie. Di conseguenza, diverse ricerche si sono concentrate sullo sviluppo di sospensioni innovative per permettere ai veicoli ferroviari di affrontare in maniera adeguata le sfide addizionali introdotte dalle velocità più elevate. In questo contesto, questa tesi propone metodologie virtuali e sperimentali per assistere lo sviluppo di sospensioni innovative per aumentare le prestazioni dinamiche di veicoli ferroviari ad alta velocità. Metodologie di modellazione e calibrazione di sospensioni meccaniche basate su approcci a parametri concentrati sono proposte per simulare la risposta dinamica di prototipi di smorzatori idraulici, mirando a quantificare l'influenza di questi componenti sulle prestazioni dinamiche di veicoli ferroviari tramite co-simulazioni con modelli Multibody. Inoltre, specifiche procedure sperimentali basate su approccio Hardware-In-the-Loop (HIL) sono presentate. Un primo banco prova ideato per studiare la dinamica laterale di veicoli ferroviari è proposto per testare smorzatori anti-serpeggio, e analisi comparative tra diversi prototipi sono presentate per mostrare l'influenza di soluzioni diverse sulla stabilità di marcia del veicolo. In seguito viene illustrato un secondo banco prova HIL dedicato allo studio del comfort vibrazionale dei passeggeri, in cui un modello in grado di considerare i primi modi deformabili della carrozza viene proposto per simulare la dinamica verticale del veicolo. Le metodologie precedentemente illustrate sono state utilizzate per sviluppare uno smorzatore anti-serpeggio innovativo in grado di alleviare il compromesso tra la necessità di aumentare la stabilità del veicolo ad alta velocità e il bisogno di contenere l'aumento della resistenza di curvatura del carrello durante la negoziazione di curve strette a bassa velocità. In seguito, uno smorzatore secondario verticale semi-attivo, ideato per aumentare il comfort vibrazionale dei passeggeri, viene costruito e testato su un banco HIL dedicato per quantificare la sua robustezza e la sua capacità di reagire a danneggiamenti inattesi durante condizioni di utilizzo reali. Per investigare ulteriormente la possibilità di migliorare il comfort di marcia di veicoli ferroviari, i potenziali benefici derivanti dall'introduzione di una sospensione idraulica interconnessa (HIS) al primo stadio di sospensione vengono quantificati tramite un'analisi numerica. I risultati mostrano che l'implementazione di sospensioni HIS nello stadio di sospensione primario hanno la capacità di alleviare il compromesso tra comfort e sicurezza di marcia che attualmente limita l'ottimizzazione dei tradizionali componenti passivi.
Design of innovative smart suspension components for railway vehicles
Isacchi, Gioele
2024/2025
Abstract
Nowadays, the increase of the commercial speed of railway vehicles is a global trend and major economical investments are being devoted to expand the length of high-speed railway lines. As a consequence, many research efforts have being focused on the development of innovative solutions to allow rail vehicles to properly face the additional challenges caused by higher speeds. In this context, this thesis proposes virtual and experimental methodologies to assist the development of new suspension components to improve dynamic performance of rail vehicles. Modelling and calibration methodologies based on lumped parameters approach are proposed to simulate the response of hydraulic damper prototypes, with the aim of quantifying their influence on the vehicle performances by means of co-simulation with Multibody (MB) train models. Moreover, dedicated experimental procedures based on the Hardware-In-the-Loop (HIL) methodology are proposed. A first HIL test rig to study the lateral dynamics of a rail vehicle is proposed to test yaw damper components, and comparative analyses are performed between different yaw dampers focusing on stability performance. A second HIL test rig, simulating the vertical dynamics of a rail vehicle featuring also the first deformable modes of the car body, is also illustrated. The aforementioned methodologies are implemented to study an innovative smart passive yaw damper designed to mitigate the trade-off between high-speed stabilizing effect and low-speed steering resistance. Then, a semi-active secondary vertical damper designed to improve the ride comfort of rail vehicle is prototyped and tested by means of HIL approach to quantify its robustness and its capability to deal with unexpected failures. To further investigate the possibility of improving ride comfort of rail vehicles, a numerical investigation is proposed to illustrate the potential benefits of introducing a passive Hydraulic Interconnected Suspension (HIS) at the primary suspension stage. The analysis demonstrates that replacing primary vertical dampers with HIS can alleviate the trade-off between ride comfort and running safety performances of high-speed rail vehicles.| File | Dimensione | Formato | |
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2025_02_Isacchi.pdf
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Descrizione: PhD Thesis
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https://hdl.handle.net/10589/233913