5 research outputs found

    Railway-induced ground vibrations – a review of vehicle effects

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    This paper is a review of the effect of vehicle characteristics on ground- and track borne-vibrations from railways. It combines traditional theory with modern thinking and uses a range of numerical analysis and experimental results to provide a broad analysis of the subject area. First, the effect of different train types on vibration propagation is investigated. Then, despite not being the focus of this work, numerical approaches to vibration propagation modelling within the track and soil are briefly touched upon. Next an in-depth discussion is presented related to the evolution of numerical models, with analysis of the suitability of various modelling approaches for analysing vehicle effects. The differences between quasi-static and dynamic characteristics are also discussed with insights into defects such as wheel/rail irregularities. Additionally, as an appendix, a modest database of train types are presented along with detailed information related to their physical attributes. It is hoped that this information may provide assistance to future researchers attempting to simulate railway vehicle vibrations. It is concluded that train type and the contact conditions at the wheel/rail interface can be influential in the generation of vibration. Therefore, where possible, when using numerical approach, the vehicle should be modelled in detail. Additionally, it was found that there are a wide variety of modelling approaches capable of simulating train types effects. If non-linear behaviour needs to be included in the model, then time domain simulations are preferable, however if the system can be assumed linear then frequency domain simulations are suitable due to their reduced computational demand

    Coupling a DEM material model to multibody construction equipment

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    Particle simulation with the Discrete Element Method (DEM) is well-established and widely used in soil dynamics related applications. The wide range of applications can be envisaged, for instance, in automotive engineering, material handling and manufacturing. In recent years, the Fraunhofer ITWM has developed and implemented its own DEM code entitled "GRAnular Physics Engine (GRAPE)" which is currently specialized for granular materials. In this paper, we present the technical realization of GRAPE’s communication interface in the construction equipment development context that has been evolved during a project collaboration between the Fraunhofer ITWM and Volvo CE. Moreover, we address numerical studies with a focus on GRAPE internal parameters and co-simulation settings by applying the interface to couple a multibody wheel loader model and a multibody hauler model, respectively
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