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Fastening systems play a significant role in railroad track dynamics. In this paper, three approaches are investigated for rail fastenings modeling using FEM: (1) spring–damper pairs covering the areas representing the fastening connections; (2) a solid-load approach that explicitly models the solid baseplates and includes toe loads by applying external loads; and (3) a solid-spring approach that takes into account the coupling of rail with the ties by using prestressed springs. Experimental tests were carried out to evaluate the performance of the FEM models. The mode shapes obtained from the FEM models and the experiments were used for the evaluation. A measurement quantifying the similarity of the mode shapes was proposed, which considers both shape similarity and distance similarity. The results showed that the rail foot's mode shapes obtained from the model using the spring–damper approach demonstrated the most similarity with the ones obtained from the experiments. [ABSTRACT FROM AUTHOR]

Vibration energy harvesters (VEHs) can utilize the vibration of the track to generate electricity and provide power for other devices within the harvester. To analyze whether energy harvesters arranged in an array harm track operation, we conducted a simulation analysis. Based on the vehicle–track coupling model, the influence of inductive electromotive force on track vibration was analyzed and compared with the simulation results obtained from the classical vehicle–track coupling model. The rail vibration displacement was reduced from 0.5 to 0.0692 mm, and the maximum vibration acceleration of the rail was reduced from 2.3759 to 0.4534 m/s2. The energy harvester can attenuate the vibration of the track significantly, and has a minor influence on the regular operation of the track. The vibration of a railway can be transformed to electric energy and used to power sensors at the railway side and train sides, such as velocity sensors, temperature sensors, accelerometers, wireless transmission modules, and other wireless sensor network (WSN) devices. It also can be used as backup power for the auxiliary load on the railway side, such as traffic lights and speed measuring radar. A vibration energy harvester installed at the fastener has a simple structure and can provide enough power for WSN sensors. It provides a good energy supply for line-side monitors and auxiliary devices. Because safety is the most critical issue for track devices, the effect of the installation of VEHs on the operation of the track should be analyzed. The vibration of a track with a fastener VEH is less than that without a VEH, which will reduce the impact of vibration on the environment and ensure the safe running of trains. This method also applies to the safety analysis of other track energy harvesting devices. [ABSTRACT FROM AUTHOR]

This study proposes an innovative type of simple connection utilizing power-actuated fasteners to join a cold-formed steel channel to a rectangular hollow section column via a web-side plate or a T-section. An experimental program composed of 26 specimens was carried out to investigate the behavior of the connections under the combination of shear and rotation. The experimental results are discussed in two limit states including bearing and pull-out by shear. An analytical model is proposed to predict the shear strength of the connections based on the provided information of vectorial force at a fastener, displacement, and rotation at the connections. The proposed model yields a conservative prediction for the tested connections with a mean test-to-prediction ratio of 1.05 and the coefficient of variation of 6% or 9%, depending on the limit state. A design example is provided to illustrate the implementation of the proposed model in practice. [ABSTRACT FROM AUTHOR]