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Dynamic performance of bridge piers impacted by heavy trucks

Huang Yao

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

173--185

EN

Vehicle-bridge collision accidents often result in significant economic losses and negative social effects, with heavy trucks being the most destructive to bridge structures. Therefore, this study uses a high-precision finite element method to investigate the impact resistance of concrete bridge piers when subjected to heavy truck impact. The main conclusions of this paper are as follows: (1) When heavy trucks collide with bridge piers, two peak impact forces are generated due to engine and cargo collisions. The peak collision force generated by engine impact is 17.7% greater than that generated by cargo impact. (2) The damage to the bridge, when impacted by heavy trucks, is mainly concentrated on the affected pier. The primary damage characteristics of the bridge piers include punching shear damage at the impact point, tensile damage at the backside, and shear damage at the pier top. (3) The peak values of shear force and bending moment both appear at the bottom of the pier, and the combination of the two causes serious flexural-shear failure damage at the bottom of the pier. (4) The axial force is fluted along the pier height, and the axial force at the top and bottom of the pier is the largest, while the axial force at the middle section is relatively small. The instantaneous axial force of bridge pier will reach more than 2 times the axial force during operational period, seriously threatening the safety of bridge. Overall, this study provides valuable insights into the impact resistance of concrete bridge piers when subjected to heavy truck impact, which can help engineers and policymakers in designing more robust and safer bridges.

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Dynamic performance and stability analysis of an active inerter-based suspension with time-delayed acceleration feedback control

Wang Yong, Jin Xian-Yu, Zhang Yun-Shun, Ding Hu, Chen Li-Qun

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 2

art. no. e140687

EN

An active inerter-based suspension with acceleration feedback control is proposed in this paper, the time delay generated in the controllers and actuators is considered, which constitutes the time-delayed active inerter-based (TDA-IB) suspension. The dynamic equation of the TDA-IB suspension is established and is a neutral type of delay differential equation (NDDE) in which the time delay exists in the highestorder derivative. The stability analysis is conducted by calculating the number of unstable characteristic roots based on the definite integral stability method, the stable and unstable regions are determined. The effect of time delay and feedback gain on the dynamic performance of the TDA-IB suspension under harmonic, random, and shock excitations is studied in detail and compared with the parallel-connected inerterbased (PC-IB) and traditional suspensions. The results show that the TDA-IB suspension is asymptotically stable for smaller feedback gain and time delay, through increasing the feedback gain, the stable regions shrink, and a smaller time delay could cause the system to become unstable. Furthermore, the time delay could regulate the resonance peak around the unsprung mass natural frequency and generate multiple high-frequency resonance peaks. If the time delay is chosen appropriately and falls into the stable range, the TDA-IB suspension could improve the dynamic performance for the suspension stroke and dynamic tire load while having a deterioration for the vehicle body acceleration compared with the PC-IB and traditional suspensions.

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Analysis of the conditions for the exhaustion of the stability margin in the rail track of freight cars with three-piece bogies

Domin Yurii V., Domin Rostysla Yu., Cherniak Ganna Yu., Nozhenko Volodymyr S.

Archives of Transport

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2021

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Vol. 57, iss. 1

119--129

EN

The research on improvement of methodical approaches to definition of the probable reasons of infringement of conditions of stability of freight cars from derailment is carried out. Using a basic computer model of the dynamics of a freight car, the influence of the characteristics of the technical condition of their running gear and track on the indicators of empty cars stability from derailment was studied through the computational experiment. The article presents the main statements of the research methodology, which provides the analysis of probable causes of derailment of freight cars by conducting a series of numerical experiments with logging the progress of calculations and saving the results. Factor analysis was used to interpret the calculated data with an assessment of each of the factors influence or their combination on the probability of derailment. The developed procedure of the simulation experiment provides a step-by-step study of the freight cars derailment conditions, including factors structuring and ranking, development of experimental plan, calculating coefficients of wheel pairs resistance to derailment from rails, provided that the wheel flange rolls onto the rail head, and determining the degree of influence of relevant factors on the dynamic stability of cars from derailment. A comparative analysis of the stability of cars in rail tracks was performed using the introduced concept of the combined coefficient of stability of wheel pairs against derailment. Determining the probable causes of car derailment is based on scanning the parameter field. The results of the parametric study revealed the degree of influence on the freight cars stability of running gear technical condition characteristics. In particular, it is determined that the most dangerous in terms of stability loss of empty cars in the track is the exceeding of the wedges of the vibration dampers.

4

Comparative study of fault-tolerant performance of a segmented rotor SRM and a conventional SRM

Sun X., Xue Z., Han S., Chen L., Xu X., Yang Z.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 3

375--381

EN

Due to the separation of magnetic field, electrical isolation and thermal isolation, motor drives possess a high fault-tolerance characteristic. In this paper, comparative study of mutual inductance between the proposed segmented rotor switched reluctance motor (SSRM) and the conventional switched reluctance motor (SRM) is carried out first, illustrating that the proposed SSRM has less mutual inductance between phases than the conventional SRM. In addition, if winding faults or power converter faults lead to phase failure, a comparative analysis on fault-tolerant performance under phase failure condition between the proposed SSRM and the conventional SRM is simulated in detail using the finite element method (FEM). Simulation results reveal that dynamic performance of the proposed SSRM, including output torque and phase current, is better than that of the conventional SRM. That is, the capacity of operating with the fault under phase failure condition in the proposed SSRM is superior to that in the conventional SRM.