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A comparative study of wave localization in locally resonant Thue–Morse, Rudin–Shapiro and Period-Doubling aperiodic structures

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Acta Mechanica Solida Sinica 2017年第3期30卷 271-284页

作者： Zhizhong Yan yangyang wang Chuanzeng Zhang School of Mathematics and Statistics Beijing Institute of Technology Department of Civil Engineering University of Siegen

The localization characteristics of the in-plane elastic waves in locally resonant aperiodic phononic crystals are examined in this study. In particular, the phononic crystals generated according to the Thue-Morse, Rudin-Shapiro and Period-Doubling sequences are theoretically investigated by using the extended transfer matrix method. For comparison, the binary and ternary locally resonant systems are considered, and their band structures are characterized by using the localization factors. Moreover, the influences of structural arrangement, material combination, incidence angle, number of components, length ratio, and random disorder on the band structures are also discussed. Some novel and interesting phenomena are observed and discussed.

关键词： Phononic crystals Aperiodicity Wave localization Localization factor Transfer matrix method

A tool for tracing network data plane via SDN/OpenFlow

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Science China(Information Sciences) 2017年第2期60卷 74-86页

作者： yangyang wang Jun BI Keyao ZHANG Institute for Network Sciences and Cyberspace Tsinghua University Tsinghua National Laboratory for Information Science and Technology (TNList) Department of Computer Science Tsinghua University

SDN provides an approach to create desired network forwarding plane by programming *** a large-scale SDN network comprised of multiple domains and running multiple controller applications, it is difficult to measure and diagnose the problems of flow tables in data plane. Tracing the forwarding path of SDN is one of effective way for data plane state measurement. Previously proposed methods for debugging SDN were applied to a single administrative domain. There is less effort to trace the flow entries of the data plane in large-scale multi-domain SDN networks. In this paper, we propose a method of software defined data plane tracing in large-scale multi-domain SDN networks. Our method can trace forwarding paths, and get the matched flow entries and other customized trace information. We present the designs compatible with Open Flow 1.0 and1.3 switches. The performance and deployment effect are evaluated by simulation test and analysis. It shows that our method has better performance than traditional IP traceroute, and its deployment at about 20% of AS nodes can enable 70% of AS paths to be traceable.

关键词： software defined networking data plane network measurement traceroute Internet routing

Dynamic Response of Two-Degree-of-Freedom Riserless Drill String for Vortex-Induced Vibration Suppression and Enhancement

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Journal of Ocean University of China 2023年第3期22卷 612-626页

作者： wang Yu LOU Min wang yangyang ZHANG Chen School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao 266580China

The mechanical behavior,dynamic evolution,and flow-field distribution of a two-degree-of-freedom riserless drill string were simulated numerically by using FLUENT fluid simulation software with the user-defined function *** rotation angular velocities before and after the critical rotation angular velocity were used as independent variables,and the reduced velocity range was ***-structure coupling was realized based on the dynamic overset grid and the SST k-ωturbulence *** reveal that the dynamic response of the riserless drill string was considerably affected by rotation and flow velocity,which are coupled with each *** cross-flow average dimensionless displacement increased with the rotation angular velocity,and rotation considerably enhanced the in-line maximum average dimensionless ***,the cross-flow amplitude caused by vortex-induced vibration was suppressed when the rotation angular velocity reached a certain *** in-line and cross-flow frequencies were the same,thereby causing the trajectory to deviate from the standard'figure-eight'shape and become a closed circle *** vortex did not fall behind the cylinder at low reduced velocity with high-rotation angular velocity,and the structure of the near-wake vortex remained *** wake of the cylinder was deflected along the cross-flow direction,thereby leading to vibration asymmetry and resulting in increased vibration instability and disordered vibration trajectories,especially at high-rotation angular velocities.

关键词： riserless drill string two-degree-of-freedom vortex-induced vibration rotation dynamic response

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Enhancing fly ash utilization in backfill materials treated with CO_(2)carbonation under ambient conditions

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International Journal of Mining Science and Technology 2023年第3期33卷 323-337页

作者： Ichhuy Ngo Liqiang Ma Jiangtao Zhai yangyang wang Key Laboratory of Deep Coal Resource Mining China University of Mining&TechnologyXuzhou 221116China

The environmental concerns resulting from coal-fired power generation that produces large amounts of CO_(2)and fly ash are of great *** mitigate,this study aims to develop a novel carbonated CO_(2)-fly ash-based backfill(CFBF)material under ambient *** performance of CFBF was investigated for different fly ash-cement ratios and compared with non-CO_(2)reacted *** fresh CFBF slurry conformed to the Herschel-Bulkley model with shear thinning *** carbonation,the yield stress of the fresh slurry increased significantly by lowering fly ash ratio due to gel *** setting times were accelerated,resulting in approximately 40.6%of increased early *** final strength decreased when incorporating a lower fly ash ratio(50%and 60%),which was related to the existing heterogeneous pores caused by rapid fluid *** strength increased with fly ash content above 70%because additional C-S(A)-H and silica gels were characterized to precipitate on the grain surface,so the binding between particles *** C-S(A)-H gel was developed through the pozzolanic reaction,where CaCO_(3)was the prerequisite calcium source obtained in the CO_(2)-fly ash ***,the maximum CO_(2)uptake efficiency was 1.39 mg-CO_(2)/*** CFBF material is feasible to co-dispose CO_(2)and fly ash in the mine goaf as negative carbon backfill materials,and simultaneously mitigates the strata movement and water lost in post-subsurface mining.

关键词： Fly ash utilization CO_(2)carbonation Ambient conditions Water conservative backfill mining Negative carbon backfill materials

Cooperative Chloride Hydrogel Electrolytes Enabling Ultralow-Temperature Aqueous Zinc Ion Batteries by the Hofmeister Effect

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Nano-Micro Letters 2022年第6期14卷 219-233页

作者： Changyuan Yan yangyang wang Xianyu Deng Yonghang Xu Shenzhen Key Laboratory of Advanced Materials School of Materials Science and EngineeringHarbin Institute of TechnologyShenzhen 518055People’s Republic of China School of Materials Science and Hydrogen Energy Foshan UniversityFoshan 528000China

Aqueous zinc ion batteries have high potential applicability for energy storage due to their reliable safety,environmental friendliness,and low ***,the freezing of aqueous electrolytes limits the normal operation of batteries at low ***,a series of high-performance and low-cost chloride hydrogel electrolytes with high concentrations and low freezing points are *** electrochemical windows of the chloride hydrogel electrolytes are enlarged by>1 V under cryogenic conditions due to the obvious evolution of hydrogen bonds,which highly facilitates the operation of electrolytes at ultralow temperatures,as evidenced by the low-temperature Raman spectroscopy and linear scanning *** on the Hofmeister effect,the hydrogen-bond network of the cooperative chloride hydrogel electrolyte comprising 3 M ZnCl_(2)and 6 M LiCl can be strongly interrupted,thus exhibiting a sufficient ionic conductivity of 1.14 mS cm;and a low activation energy of 0.21 e V at-50℃.This superior electrolyte endows a polyaniline/Zn battery with a remarkable discharge specific capacity of 96.5 mAh g;at-50℃,while the capacity retention remains~100%after 2000 *** results will broaden the basic understanding of chloride hydrogel electrolytes and provide new insights into the development of ultralow-temperature aqueous batteries.

关键词： Chloride hydrogel Electrochemical window Cooperative effect Hydrogen-bond Ultralow temperature Aqueous zinc ion battery

A Trajectory Planning Method of Automatic Lane Change Based on Dynamic Safety Domain

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Automotive Innovation 2023年第3期6卷 466-480页

作者： yangyang wang Xiaolang Cao Yulun Hu School of Automotive Studies Tongji UniversityShanghai 200092China

Traditional research on automatic lane change has primarily focused on high-speed scenarios and has not considered the dynamic state changes of surrounding *** paper addresses this problem by proposing a trajectory planning method to enable automatic lane change at medium and low *** method is based on a dynamic safety domain model,which takes into account the actual state change of surrounding vehicles,as well as the upper boundary of the safety domain for collision avoidance and the lower boundary of comfort for vehicle *** proposed method involves the quantification of the safety and comfort boundaries through parametric modeling of the vehicle.A quintic polynomial trajectory planning method is proposed and evaluated through simulation and testing,resulting in improved safety and comfort for automatic lane change.

关键词： Automatic lane change Dynamic safety domain Trajectory planning Autonomous driving

Evaluation of Automatic Lane-Change Model Based on Vehicle Cluster Generalized Dynamic System

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Automotive Innovation 2022年第1期5卷 91-104页

作者： yangyang wang Xiaolang Cao Xinyuan Ma School of Automotive Studies Tongji UniversityShanghaiChina

The lane-change transportation research usually focuses on the efficiency and stability of the macro traffic flow while ignoring the driving comfort of individual *** many studies of lane-change models are often limited to the performance of a single vehicle,which leads to a lack of macroscopic *** solve the above limitations,an automatic lane-change generalized dynamic model is *** this model,the lane-change behavior of an individual vehicle is considered as the generalized excitation and the restraining force between vehicles is described with the car-following *** and micro evaluation indexes are also adopted to evaluate the automatic lane-change behavior in traffic ***,this paper proposes a modified intelligent driver model(IDM)to describe the state change process during lane *** hyperbolic tangent transition function is used to eliminate the vehicle state *** simulation results show that the proposed automatic lane-change generalized dynamic model can reflect the macro and micro parameters of the traffic *** compared with the traditional IDM model,the proposed HC-IDM model achieves higher comfort performance and lower fluctuation of traffic flow.

关键词： Lane change model Generalized dynamic system IDM car-following model

Signal-Based Intelligent Hydraulic Fault Diagnosis Methods: Review and Prospects

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Chinese Journal of Mechanical Engineering 2019年第5期32卷 1-22页

作者： Juying Dai Jian Tang Shuzhan Huang yangyang wang Field Engineering College Army Engineering University

Hydraulic systems have the characteristics of strong fault concealment,powerful nonlinear time-varying signals,and a complex vibration transmission mechanism;hence,diagnosis of these systems is a *** provide accurate diagnosis results automatically,numerous studies have been carried *** them,signal-based methods are commonly used,which employ signal processing techniques based on the state signal used for extracting features,and further input the features into the classifier for fault ***,their main deficiencies include the following:(1)The features are manually designed and thus may have a lack of objectivity.(2)For signal processing,feature extraction and pattern recognition are conducted using independent models,which cannot be jointly optimized globally.(3)The machine learning algorithms adopted by these methods have a shallow architecture,which limits their capacity to deeply mine the essential features of a *** a breakthrough in artificial intelligence,deep learning holds the potential to overcome such *** on deep learning,deep neural networks(DNNs)can automatically learn the complex nonlinear relations implied in a signal,can be globally optimized,and can obtain the high-level features of multi-dimensional *** this paper,the main technology used in an intelligent fault diagnosis and the current research status of hydraulic system fault diagnosis are summarized and *** significant prospect of applying deep learning in the field of intelligent fault diagnosis is presented,and the main ideas,methods,and principles of several typical DNNs are described and *** commonality between a fault diagnosis and other issues regarding typical pattern recognition are analyzed,and research ideas for applying DNNs for hydraulic fault diagnosis are ***,the research advantages and development trend of DNNs(both domestically and overseas)as applied to an intelligent fault diagnosis are revie

关键词： Hydraulic system Intelligent fault diagnosis Deep neural networks

Optimizing Winding Angles of Reinforced Thermoplastic Pipes Based on Progressive Failure Criterion

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Journal of Ocean University of China 2021年第5期20卷 1067-1078页

作者： wang yangyang LOU Min ZENG Xin DONG Wenyi wang Sen School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China Key Laboratory of Unconventional Oil&Gas Development(China)University of Petroleum(East China) Ministry of EducationQingdao 266580China Zoomlion Heavy Industry Science&Technology Co. Ltd.Changsha 410013China China Offshore Oil Engineering(Qingdao)Co. Ltd.Qingdao 266520China Weihai Nacheon Pipeline Co. Ltd.Weihai 264400China

This paper examines a scheme to optimize the multiple winding angles of reinforced thermoplastic pipes(RTPs)under internal and external *** consider the nonlinear mechanical behavior of the material under changes of winding angle due to deformation,we use three-dimensional(3D)thick-walled cylinder theory with the 3D Hashin failure criterion and theory of the evolution of damage to composite materials,to formulate a model that analyzes the progressive failure of *** accuracy of the model was verified by experiments.A model to optimize the multiple winding angles of the RTPs was then established using the model for progressive failure analysis and a multi-island genetic *** optimal scheme for winding angles of RTPs capable of withstanding the maximum internal/external pressure was *** simulation results showed that the ply number of the reinforced layer has a prominent nonlinear effect on the internal and external pressure capacity of the *** with RTPs with a single angle of±55°,the multiple winding angle overlay scheme based on the multi-angle optimization model improved the internal and external pressure capacity of the RTPs,and the improvement in the external pressure capacity was significantly better than the internal pressure carrying capacity.

关键词： reinforced thermoplastic pipes 3D thick-walled cylinder theory multi-island genetic algorithm pressure capacity