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Negative Poisson’s ratio locally resonant seismic metamaterials vibration isolation barrier

Acta Mechanica Sinica 2024年第8期40卷 239-252页

作者： Haibin Ding Nianyong Huang Muhammad Changjie Xu Lihong Tonog State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure Nanchang330013China Institute of Geotechnical Engineering School of Civil Engineering and ArchitectureEast China Jiaotong UniversityNanchang330013China Department of Mechanical Manufacturing and Biomedical EngineeringTrinity College DublinDublinD02PN40Ireland Department of Mechanical Engineering University of GalwayUniversity RoadGalwayH91 HX31Ireland

In recent decades,the application of seismic metamaterials to protect civil infrastructures being free of the damage of earthquakes has been attracting extensive ***,the proposed locally resonant seismic metamaterials provide the probability of isolating the low-frequency seismic wave using a small-size isolation ***,in previous studies,the energy absorption properties of locally resonant seismic metamaterials remain one of the least understood aspects of *** from the fascinating energy absorption characteristic of negative Poisson ratio(NPR)metamaterial,we creatively design a new seismic metamaterial structure by assembling the locally resonant seismic metamaterial and NPR metamaterial,to isolate seismic *** sound cone technique combining the transmission spectrum is employed to identify the surface wave from the hybrid *** generation mechanism of frequency bandgap and the isolation effectiveness of the proposed seismic metamaterial are discussed in *** results indicate that the generation of ultra-low and ultra-wide frequency bandgap with the range of 0.65 Hz–18.9 Hz is attributed to the locally resonant and energy absorption of the proposed seismic metamaterial structure and the excellent isolation effect is achieved by transforming the surface wave into the bulk *** frequency bandgap narrows as the distance increases between each *** addition,the mechanical properties of the NPR bearing,such as the Poisson ratio,mass density,and elastic modulus,have remarkable impact on the frequency bandgap,especially on the upper bound *** practical engineering,the NPR bearing with a low Poisson ratio,small mass density,and high elastic modulus is suggested for the design of the NPR locally resonant seismic metamaterial *** domain analysis for the practical seismic wave verifies that the proposed seismic metamaterial has a promising application in isolating ultra-low and ultra-wi

关键词： Seismic metamaterials Locally resonant Negative Poisson ratio(NPR) Seismic waves Frequency bandgap Vibration isolation barrier

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Recent advancement of flow-induced piezoelectric vibration energy harvesting techniques:principles,structures,and nonlinear designs

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Applied Mathematics and Mechanics(English Edition) 2022年第7期43卷 959-978页

作者： Dongxing CAO Junru WANG Xiangying GUO S.K.LAI Yongjun SHEN Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures Beijing 100124China School of Automation Beijing Information Science and Technology UniversityBeiing 100192China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center The Hong Kong Polytechnic UniversityKowloonHong KongChina State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Energy harvesting induced from flowing fluids(e.g.,air and water flows)is a well-known process,which can be regarded as a sustainable and renewable energy *** addition to traditional high-efficiency devices(e.g.,turbines and watermills),the micro-power extracting technologies based on the flow-induced vibration(FIV)effect have sparked great concerns by virtue of their prospective applications as a self-power source for the microelectronic devices in recent *** article aims to conduct a comprehensive review for the FIV working principle and their potential applications for energy ***,various classifications of the FIV effect for energy harvesting are briefly introduced,such as vortex-induced vibration(VIV),galloping,flutter,and wake-induced vibration(WIV).Next,the development of FIV energy harvesting techniques is reviewed to discuss the research works in the past three *** application of hybrid FIV energy harvesting techniques that can enhance the harvesting performance is also ***,the nonlinear designs of FIV-based energy harvesters are reported in this study,e.g.,multi-stability and limit-cycle oscillation(LCO)***,advanced FIV-based energy harvesting studies for fluid engineering applications are briefly ***,conclusions and future outlook are summarized.

关键词： vibration-driven energy harvesting flow-induced vibration(FIV) piezoelectric approach nonlinear design

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Fatigue Properties and Damage Evolution of Cfrp/Al Bolted Joint Under High Load Level Using Micro-Ct Technology

SSRN

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SSRN 2024年

作者： Jiang, Lanxin Yang, Long Yang, Bing Liao, Zhen Xiao, Shoune Xiong, Hongzi School of Mechanical Engineering Sichuan University Chengdu610065 China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu610031 China Sichuan University of Science and Engineering School of Mechanical Engineering 644004 China

Despite the widespread engineering application of bolted joints between aluminum alloy (Al) and carbon fiber reinforced plastic (CFRP), the fatigue failure mechanism remains unknown. Tension-tension fatigue experiments were performed on CFRP/AL bolted single lap joints (SLJs) at high load levels in this investigation. Two stacking sequences ([±45]12 and [0/90, ±45]3s), were developed together with multiple load levels LR ranging from 0.75 to 0.96. To further investigate the fatigue failure mechanism of CFRP, micro X-ray computed tomography (µCT) was utilized for non-destructive testing, the three-dimensional (3D) models were reconstructed, and the pores were quantified and evaluated. The findings indicated that failures in Al occurred at lower load levels, whereas failures in CFRP occurred at higher load levels. Additionally, a competitive failure was observed at a ratio of 0.923 to 0.95. CT analysis revealed that pores were observed to initiate and expand noticeably in the ±45 layer. An increase in both the load level and the number of cycles will cause pores to expand and aggregate. This study can explore the application of CT technology in the field of CFRP fatigue research. © 2024, The Authors. All rights reserved.

关键词： Carbon fiber reinforced plastics

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Improved Multistep Model Predictive Control for Six-Step Operation of Traction PMSM Drives

Improved Multistep Model Predictive Control for Six-Step Ope...

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Workshop on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)

作者： Zhenyao Sun Shuai Xu Guangtong Ma Juri Jatskevich State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu China Department of Electrical and Computer Engineering The University of British Columbia Vancouver Canada

Model predictive control (MPC) has recently been considered for many permanent magnet synchronous machine (PMSM) drive applications. However, the conventional MPC lacks accurate current tracking and fast dynamic responses in the overmodulation region and the six-step operation, which limits its application areas. This paper proposes a six-step operation scheme based on MPC for PMSM drives in traction applications. The current trajectory long-horizon prediction and the average current-based objective function are introduced to determine the optimal switching instants. To enhance the method’s precision, a trapezoidal integration rule has been used in the prediction step. The voltage angle control principle is introduced to clamp the voltage vectors. The effectiveness of the proposed method has been validated by detailed studies. The proposed method is demonstrated to have excellent current tracking accuracy and fast dynamic response in six-step operation, which is an advantage over existing methods.

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Mechanical properties of segmental joints strengthened by assembled reinforcement structures for shield tunnel linings

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第12期25卷 1037-1050页

作者： Zhiguo YAN Sihang AI Xia YANG Long ZHOU Bing FAN Huan PANG State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China Jinan Rail Transit Group Co. Ltd.Jinan 250101China School of Safety Science and Engineering(School of Emergency Management) Nanjing University of Science and TechnologyNanjing 210094China China Railway No.5 Engineering Group Co. Ltd.Guiyang 550003China

We develop assembled reinforcement structures(ARSs)composed of connection parts,connecting rods,and straight bolts to strengthen segmental joints in the lining of shield *** full-scale bending experiments and numerical simulations,we investigate the deformation and failure characteristics of segmental joints strengthened by ARSs,and propose a novel optimization method for *** experimental results show that the ARSs can effectively limit the opening of a segmental joint,but also that separation can occur during loading if the connection between the ARSs and segments is not designed ***,this connection can be improved by embedding anchor parts in the *** numerical modeling,we investigate the failure modes of segmental joints strengthened by ARSs for both positive bending and negative bending loading *** the case of positive bending loading,first the concrete around the anchor parts cracks,and subsequently the concrete on the external side of the joint is *** joint failure is caused by the crushing of concrete on the external side of the *** the un-strengthened segmental joint fails with an opening of 5.884 mm,the strengthened segmental joint only opens by 0.288 mm under the same loading,corresponding to a reduction of 95.1%.In the case of negative bending loading,the concrete around the anchor parts first cracks,and then the amount of joint opening exceeds a limiting value for waterproofing(6 mm),i.e.,the joint’s failure is caused by water *** the opening of the un-strengthened segmental joint is 9.033 mm and experiences waterproofing failure,the opening of the strengthened segmental joint is only 2.793 mm under the same loading,corresponding to a reduction of 69.1%.When constructing a new shield tunnel,anchor parts could be embedded in the concrete segments in tandem with ARSs for improved resistance to joint *** existing shield tunnel linings,anchor parts cannot be embedded in the concr

关键词： Shield tunnel Segmental joint Assembled reinforcement structure(ARS) Mechanical properties

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A review on the research of noise generation mechanism and control technology in high-speed trains

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Intelligent Transportation Infrastructure 2024年第3期3卷

作者： Zhang, Linli Cheng, Gong Feng, Qingsong Sheng, Xiaozhen School of Urban Railway Transportation Shanghai University of Engineering Science Shanghai China State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang China Shanghai Engineering Research Centre of Vibration and Noise Control Technologies for Rail Transit Shanghai China

Now it is widely accepted that lightweight design is one of the necessary conditions for high-speed trains. However, a lighter vehicle body and higher operating speed will produce higher noise, making it become one of the important problems restricting the development of high-speed railway. This becomes more and more obvious as train speed increases. The noise of high-speed trains mainly come from wheel-rail noise and aerodynamic noise, with sound radiation over an ultra-wide frequency range and transmission either to the vehicle body or to the surrounding environment, which seriously affects the riding comfortableness of passengers and the life quality of surrounding residents. How to reduce the noise of high-speed trains is one of the urgent problems to be solved at this stage. This paper will introduce the research progress of the generation mechanism and corresponding control technology of different noise sources in high-speed trains;discuss the outstanding problems and potential methods in noise control. Finally, we also propose possible comprehensive strategies for noise optimization, with a view to providing some useful references for related researchers and engineers. © The Author(s) 2024. Published by Oxford University Press and Southwest Jiaotong University.

关键词： aerodynamic noise control technology generation mechanism High-speed trains wheel-rail noise

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An Intelligent Fault Diagnosis Model Based on FastDTW for railway Turnout 13

An Intelligent Fault Diagnosis Model Based on FastDTW for Ra...

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13th EAI International Conference on Mobile Multimedia Communications, Mobimedia 2020

作者： Wen-Jiang, Ji Zuo, Yuan Hei, XIN-Hong Fei, Rong School of Computer Science and Engineering Xi'an University of Technology Xi'an China State Key Laboratory of Rail Transit Engineering Informatization FSDI Xi'an China

ISBN: (纸本)9781631902710

The turnout handles the direction of the train which is one of the key equipment in the railway transportation system. In this paper, by using real action current data obtained from switch machine model ***7, a turnout fault diagnosis model based on the FastDTW pattern recognition algorithm was proposed. Firstly, the original current curve was segmented relate to the features of them. Then the warping path distance between the standard sample and the tested current curve was obtained according to FastDTW algorithm. Finally a dynamic optimized threshold was used to confirm whether there is a fault happened in the turnout. According to the experiment results, the proposed diagnose model without the prior knowledge of fault samples can works well both with single and double acting type turnout machines, owning to the following elements: the diagnose accuracy can be more than 96%, the time-cost can be improved more than 5 times compared with traditional DTW based algorithms. Copyright © 2020 EAI.

关键词： Failure analysis

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Fluid-Structure Interaction Analysis of the 5 Mw Oc4 Semi-Submersible Floating Offshore Wind Turbine Under the Wind and Wave Effects

SSRN

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SSRN 2024年

作者： Yu, Wanli Wang, Piguang Zhao, Mi Xi, Renqiang Du, Xiuli Key Laboratory of Urban Security and Disaster Engineering Ministry of Education Beijing University of Technology Beijing100124 China State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of Technology Beijing100124 China School of Mechanical Engineering and Rail Transit Changzhou University Changzhou Jiangsu213164 China

In this study, the numerical model for simulating coupled interactions of floating offshore wind turbine (FOWT) with large-scale ocean waves and atmospheric turbulence were established. The fluid volume method combined with overset mesh was utilized to solve the fluid-induced dynamic motion of the FOWT in a multiphase flow consisting of water and air by Fluent. The FOWT was analyzed by integrating the structural dynamics model and CFD model with fluid-structure interaction (FSI). Firstly, the effects of the platform’s surge, pitch and yaw motions on the aerodynamic performance of the FOWT were simulated. Secondly, the fully coupled computation of the FOWT was carried out with the established numerical model. The aerodynamic hydrodynamic interactions of the FOWT under the combined effect of wind and wave were simulated. The complex unsteady flow fields considering blade and tower interference effects among blade‐tip vortices, shedding vortices, and turbulent wakes are numerically visualized and investigated in detail. Furthermore, the effects of waves, inflow winds, and blade and tower flexibility were investigated by establishing a one/two-way FSI model. The aeroelastic response time responses and the aerodynamic loading time series of the wind turbine are comparatively analyzed. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Determination of Wheel Polygonal Wear Limit and Fatigue Life of railway Bogie Frames Considering Wheel/rail Excitation

SSRN

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SSRN 2024年

作者： Peng, Bo Wu, Xingwen Zhang, Zhenxian Yang, Ningrui Hu, Feifei Wang, Ping Mi, Caiying Chi, Maoru Wu, Shengchuan School of Mechanical Engineering Southwest Jiaotong University Chengdu610036 China State key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu610036 China Key Laboratory of High-speed Railway Engineering the Ministry of Education Southwest Jiaotong University Chengdu610031 China

This paper presents an innovative method for determining the fatigue life of railway bogie frames with track irregularities and wheel polygonal wear. This method was employed to predict wheel polygon limits. Firstly, a comprehensive coupled vehicle-track system dynamic model was established. The new model was validated by comparing the numerical results with those of field tests. Secondly, the dynamic stress characteristic of the bogie frame with different excitation forms were investigated. A methodology was proposed to compile the stress spectra of bogie frame by considering the influence of the wheel polygonal wear. This approach enabled the construction of comprehensive stress spectra by considering influences arising from both track irregularities and wheel polygonal wear. Subsequently, the stress spectra of the concerned positions on the bogie frame were developed and further used to study the influence of wheel polygonal wear amplitude on the fatigue life of the bogie frame. This facilitated the development of the maintenance limit of wheel polygonal wear from fatigue life perspective. The results suggest that the maintenance limit of wheel polygonal wear should not exceed 0.08 mm in the presence of the 24th-order wheel polygon for a typical high-speed train operating at a maximum speed of 350 km/h. © 2024, The Authors. All rights reserved.

关键词： railroads

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Design, characterisation, and crushing performance of hexagonal-quadrilateral lattice-filled steel/CFRP hybrid structures

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Composites Part B: engineering 2025年 304卷

作者： Yang, Chengxing Nan, Zhao Huo, Yujia Yang, Yuhui Xu, Ping Xiao, Yihua Fang, Yining Meng, Kangpei Key Laboratory of Traffic Safety on Track Ministry of Education School of Traffic & Transportation Engineering Central South University Changsha410075 China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang330013 China National Key Laboratory of Equipment State Sensing and Smart Support National University of Defense Technology Changsha410073 China Department of Mechanical Engineering Ningbo University of Technology Ningbo315336 China

Lightweight composite structures are increasingly utilised in rail vehicle crashworthy systems due to their excellent strength-to-weight ratio and energy absorption capacity. Among these, steel/carbon fibre reinforced polymer (CFRP) hybrid square tubes offer a promising balance of structural efficiency and mechanical performance. However, conventional hybrid tubes often suffer from premature buckling and insufficient energy dissipation under axial impact. To address these limitations, this study proposes a novel energy-absorbing design by filling steel/CFRP hybrid tubes with a bio-inspired hexagonal-quadrilateral lattice structure (HQLS). The relative density of the HQLS is derived analytically, and AlSi10Mg is selected as the lattice material based on tensile characterisation. Quasi-static compression tests are conducted to validate a finite element model, achieving a simulation error below 4 %. A Tcl-based parametric modelling strategy is developed, enabling efficient generation of 130+ finite element models. A design of experiments (DOE) approach combining Hammersley sampling method explores the influence of lattice wall thickness (0.5–0.9 mm), unit cell height (4–7 mm), and steel/CFRP thickness ratio (0.5–2.0). Results show that lattice wall thickness most significantly affects mean crush force (MCF), enhancing it by up to 24.6 %, while the steel/CFRP thickness ratio predominantly influences specific energy absorption (SEA). A surrogate model with R2 > 0.99 and RAAE © 2025 Elsevier Ltd

关键词： Compression testing

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