Finite-element model calibration of a railway vehicle based on experimental modal parameters

a b s t r a c tRailway tracks degrade faster at transition zones to railway bridges. In modern lines, backfills with bound and unbound granular geomaterials have been used to minimize this problem. To provide insight into the behaviour of the train-track system and to fill the gap between numerical and experimental studies, the authors carried out extensive field measurements. These were then used to validate a FEM model that considers the relevant track components, earthworks and bridge; accounts for the train-track interaction using contact elements; and is very accurate in reproducing the measurements. Results showed that the backfill design fulfils its purpose in that it provides a stiffness transition from the embankment to the bridge. The dynamic component of the train-track interaction remained low. The performance of the model makes it a very useful tool to further study the railway track at critical locations, such as transition zones.

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“…11) [13,23]. was no ballast between the sleepers, which contributes to stabilize the sleeper vibration and reduce the upward motion.…”

Section: Tablementioning

confidence: 99%

Transition zones to railway bridges: Track measurements and numerical modelling

Paixão

Fortunato

Calçada

2014

Engineering Structures

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“…The general idea of virtual testing is the replacement of expensive physical tests by efficient and flexible simulation techniques. Applications can be found, for example, in aerospace industry [1,2], automotive industry [3,4], machine tool development [5], rail vehicle dynamics [6][7][8], and train passage predictions [9,10]. Moreover, virtual testing techniques are commonly used to improve existing or to design new methods in several research domains.…”

Section: Motivationmentioning

confidence: 99%

Uncertainty quantification of dynamic responses in the frequency domain in the context of virtual testing

Brehm

Deraemaeker

2015

Journal of Sound and Vibration

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a b s t r a c tFor the development of innovative materials, construction types or maintenance strategies, experimental investigations are inevitable to validate theoretical approaches in praxis. Numerical simulations, embedded in a general virtual testing approach, are alternatives to expensive experimental investigations.The statistical properties of the dynamic response in the frequency domain obtained from continuously measured data are often the basis for many developments, such as the optimization of damage indicators for structural health monitoring systems or the investigation of data-based frequency response function estimates. Two straightforward numerical simulation approaches exist to derive the statistics of a response due to random excitation and measurement errors. One approach is the sample-based technique, wherein for each excitation sample a time integration solution is needed. This can be computationally very demanding if a high accuracy of the statistical properties is of interest. The other approach consists in using the relationship between the excitation and the response directly in the frequency domain, wherein a weakly stationary process is assumed. This approach is inherently related to an infinite time response, which can hardly be derived from measured data.In this paper, a novel approach is proposed that overcomes the limitation of both aforementioned methods, by providing a fast analytical probabilistic framework for uncertainty quantification to determine accurately the statistics of short time dynamic responses. It is assumed that the structural system is known and can be described by deterministic parameters. The influences of signal processing techniques, such as linear combinations, windowing, and segmentation used in Welch's method, are considered as well. The performance of the new algorithm is investigated in comparison to both previous approaches on a three degrees of freedom system. The benchmark shows that the novel approach outperforms the sample-based approach with respect to accuracy and computational effort. In comparison with the approach based on the estimator in the frequency domain, the results are more accurate in the case of short time dynamic responses. To show the interest of the technique, the novel approach is applied to the investigation of a damage indicator, which allows developing a deep insight in the effect of typical signal processing techniques on the statistics of quantities derived from response Fourier transforms.

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“…In problems with train-bridge interaction, TBI software uses the modal superposition method for solving the dynamic problem of the bridge, and the Newmark method, for solving the dynamic problem of the train. The numerical model of Alfa Pendular train was calibrated based on experimental modal parameters, as described in detail in Ribeiro et al [24]. The contribution of 85 vibration modes for the response of the bridge, with frequencies between 2.34 and 30 Hz, was considered.…”

Section: Validationmentioning

confidence: 99%

Calibration of Dynamic Models of Railway Bridges Based on Genetic Algorithms

Ribeiro

Calçada

Delgado

2015

Computational Methods in Applied Sciences

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This chapter presents the main experimental calibration methodologies of finite element numerical models, with particular focus on methodologies based on modal parameters. In this context, the computational implementation of an iterative method based on a genetic algorithm is described. The iterative method involves the resolution of an optimization problem, which involves the minimization of an objective function by varying a set of preselected model parameters. The objective function includes residuals associated to natural frequencies and mode shapes. The proposed methodology is applied to the calibration of the dynamic models of two railway bridges, São Lourenço bridge and Alverca viaduct, both located in the northern line of the Portuguese railways in recently upgraded track sections. The calibration results demonstrate a very good agreement between numerical and experimental modal responses and a significant improvement of the numerical models before calibration. Also the stability of a significant number of parameters, considering different initial populations, proved the robustness of the genetic algorithm in the scope of the optimization of the numerical models. The updated numerical models were validated based on dynamic tests under railway traffic. The results showed an excellent agreement between numerical and experimental responses in terms of displacements and accelerations of the bridges' decks.

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Finite-element model calibration of a railway vehicle based on experimental modal parameters

Cited by 76 publications

References 24 publications

Transition zones to railway bridges: Track measurements and numerical modelling

Transition zones to railway bridges: Track measurements and numerical modelling

Uncertainty quantification of dynamic responses in the frequency domain in the context of virtual testing

Calibration of Dynamic Models of Railway Bridges Based on Genetic Algorithms

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