Measurements of the high frequency dynamic stiffness of railway ballast and subgrade

Zhang, Xianying; Thompson, D.J.; Jeong, HongSeok; Toward, Martin; Herron, David; Jones, Chris; Vincent, Nicolas

doi:10.1016/j.jsv.2019.115081

Cited by 18 publications

(5 citation statements)

References 24 publications

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“…This was achieved by measuring the dynamic compression of the resilient element (𝑢 ̃1 − 𝑢 ̃2) and the response of the lower block 𝑢 ̃2 instead of the responses of the two blocks 𝑢 ̃1 and 𝑢 ̃2. This improved method was then used in [48], [72], [82], [83]. As well as the high frequency corrections described in Section 4.1.2, Li et al [36] further improved the method [69] at low frequencies by including an estimate of the support stiffness in the formulation.…”

Section: Using Standardized Measurement Methodsmentioning

confidence: 99%

Measurement, Modeling, and Analysis of the Dynamic Properties of Resilient Elements Used for Vibration Isolation

Sun,

Thompson

2023

Journal of Vibration and Acoustics

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Resilient elements are widely applied for vibration and noise control in many areas of engineering. Their complex dynamic stiffness gives fundamental information to describe their dynamic performance and is required for predicting structure-borne sound and vibration using dynamic modelling. Many laboratory measurement methods have been developed to determine the dynamic properties of resilient elements. This paper presents a review of recent developments of the measurement methods from the perspective of force-displacement relations of the resilient element assembly rather than of their material properties. To provide context, the review begins with an introduction to modelling methods for resilient elements, especially for rubber and rubber-like isolators, and three standardized measurement methods are introduced. Recent developments are then discussed including methods to extend the frequency range, which are mainly developments of the indirect method. Mobility methods, modal-based methods, recent active frequency-based substructuring (FBS) and inverse substructuring (IS) methods to study the dynamic properties of resilient elements are also described. Laboratory test rigs and the corresponding identification methods are outlined. Methods to evaluate nonlinear dynamic properties of resilient elements by laboratory measurements are also discussed. Finally, the review is concluded by discussing advantages and limitations of the existing methods and giving suggestions for future research.

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Section: Using Standardized Measurement Methodsmentioning

confidence: 99%

Measurement, Modeling, and Analysis of the Dynamic Properties of Resilient Elements Used for Vibration Isolation

Sun,

Thompson

2023

Journal of Vibration and Acoustics

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“…The whole system can be simplified as the elastic and dashpot components of a mass-spring-damper single degree-of-freedom system in this condition (Zand, J. v. t. 1994;Kaewunruen, S. and Remennikov, A. 2021;Zhang, X., et al, 2020). In the vertical direction, the dynamic characteristics of the MRE railway pad can be described by a classic motion equation: Frontiers in Materials frontiersin.org where m p , c p , and k p represent the effective mass, damping and stiffness of the MRE railway pad, respectively; f(t) is the dynamic force on the single degree-of-freedom system; € x, _ x and x are the displacement, speed and acceleration of the excitation block.…”

Section: Dynamic Characteristicsmentioning

confidence: 99%

Development of magnetorheological elastomer railway pads with a tunable stiffness/damping property for railway fastening systems

Cui

Liu²,

Zhou³

et al. 2023

Front. Mater.

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The railway pad plays an irreplaceable role in isolating the vibration and noise from rail/wheel interaction in railway components. A railway pad with variable stiffness and damping properties can adapt to various railway operating conditions for suppressing of railway noise and vibration. Unfortunately, to meet the practical requirements in railway fastening systems, which the railway pad should be able to bear heavy loads with low stiffness, both the material development and structural design need to be addressed for the application of magnetorheological elastomer (MRE). In this work, an MRE railway pad is designed, developed and experimentally tested. As illustrated by experimental results, the obtained MRE materials illustrate an obvious magnetorheological effect with the highest efficiency of 171% on storage modulus and 70% on loss factor. Coupling with the magnet controlling unit, the MRE railway pad is capable to control the stiffness and damping property under high loads. By adjusting the coil’s current from 0 A to 5 A, its static stiffness exhibits an enhancement from 37.9 kN/mm to 68.4 kN/mm, and the damping property increases from 8776.3 N•s/m to 10866.3 N•s/m. These results in this study are not only a successful demonstration of delivering a tunable stiffness and damping capability of the railway pad, but also pave the way for the development of MRE materials to achieve more rational applications.

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Section: Cross-tie Condition and Supportmentioning

confidence: 99%

“…The track modulus value used in BOEF can be considered as a combined parameter that includes local stiffness 1 of the individual components of the track substructure under the rail such as the cross-ties, fasteners/pads, ballast and subgrade. 37,38 Because the cross-tie condition will change the track support and thus the track modulus, 39 the nonlinear relationship between cross-tie stiffness and local track modulus has been defined by some studies as follow 40–42 : k=f(11kp+1kt+1kb+1ks) where k p , k t , k b , and k s are the stiffnesses of the pad (if used), the cross-tie, the ballast, and the subgrade, respectively. Analyzing the sensitivity of k by changing the values of k t can be approximated by an exponential function.…”

Section: Introductionmentioning

confidence: 99%

Forecasting cross-tie condition based on the dynamic adjacent support using a theory-guided neural network model

Soufiane,

Zarembski,

Palese

2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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Cross-ties represent a key infrastructure asset of the railroad industry. Recent research has shown that the cross-tie life is not only affected by the traditionally defined load and track design parameters but also by support condition, and in particular, support condition as represented by the condition of adjacent cross-ties. This paper builds upon the recent research and is focused on predicting a cross-tie’s future condition as a function of the changing condition of the surrounding cross-ties. As accurate cross-tie condition information becomes available from automated inspection systems, this data allows for the development of a theoretical framework for predicting cross-tie degradation and corresponding cross-tie life. This theoretical framework allows for the modeling of the interactions between adjacent cross-ties as a complex and dynamic system. Thus, the objective of this paper is to develop a model that uses theory guided machine learning framework as supported by well-defined railroad engineering relationships, such as the Beam on Elastic Foundation theory, to forecast the cross-tie condition as a function of its adjacent cross-ties and their corresponding degradation rates. The resulting model outperformed a more conventional traditional neural network model. The theory guided machine learning model showed very good correlation with actual data exhibiting an R2 of 88.6% and an a20-index of 91% suggesting that the incorporation of domain knowledge into the machine learning model leads to demonstrably better cross-tie life prediction results.

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Measurements of the high frequency dynamic stiffness of railway ballast and subgrade

Cited by 18 publications

References 24 publications

Measurement, Modeling, and Analysis of the Dynamic Properties of Resilient Elements Used for Vibration Isolation

Measurement, Modeling, and Analysis of the Dynamic Properties of Resilient Elements Used for Vibration Isolation

Development of magnetorheological elastomer railway pads with a tunable stiffness/damping property for railway fastening systems

Forecasting cross-tie condition based on the dynamic adjacent support using a theory-guided neural network model

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