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arXiv 2024年

作者： Li, Hang Shen, Yongjun Li, Jian Dong, Jinlu Hong, Guangyang Key Laboratory of Structural Dynamics of Liaoning Province College of Sciences Northeastern University Shenyang110819 China Department of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

This paper is dedicated to clarifying and introducing the correct application of Melnikov method in fractional dynamics. Attention to the complex dynamics of hyperbolic orbits and to fractional calculus can be, respectively, traced back to Poincaré’s attack on the three-body problem a century ago and to the early days of calculus three centuries ago. Nowadays, fractional calculus has been widely applied in modeling dynamic problems across various fields due to its advantages in describing problems with non-locality. Some of these models have also been confirmed to exhibit hyperbolic orbit dynamics, and recently, they have been extensively studied based on Melnikov method, an analytical approach for homoclinic and heteroclinic orbit dynamics. Despite its decade-long application in fractional dynamics, there is a universal problem in these applications that remains to be clarified, i.e., defining fractional-order systems within finite memory boundaries leads to the neglect of perturbation calculation for parts of the stable and unstable manifolds in Melnikov analysis. After clarifying and redefining the problem, a rigorous analytical case is provided for reference. Unlike existing results, the Melnikov criterion here is derived in a globally closed form, which was previously considered unobtainable due to difficulties in the analysis of fractional-order perturbations characterized by convolution integrals with power-law type singular kernels. Finally, numerical methods are employed to verify the derived Melnikov criterion. Overall, the clarification for the problem and the presented case are expected to provide insights for future research in this topic. © 2024, CC BY-NC-ND.

关键词： Differentiation (calculus)

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A Crystal-Plasticity Cyclic Constitutive Model for the Ratchetting of Polycrystalline Material Considering Dislocation Substructures

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Acta Mechanica Solida Sinica 2020年第2期33卷 268-280页

作者： Xuehong Ren Shaopu Yang Guilin Wen Wenjie Zhao State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

A crystal-plasticity cyclic constitutive model of polycrystalline material considering intra-granular heterogeneous dislocation substructures,in terms of three dislocation categories:mobile dislocations,immobile dislocations in the cell interiors and in the cell walls,is proposed based on the existing microscopic and macroscopic experimental *** multiplication,annihilation,rearrangement and immobilization of dislocations on each slip system are taken as the basic evolutionary mechanism of the three dislocation categories,and the cross-slip of screw dislocations is viewed as the dynamic recovery mechanism at room *** slip resistance associated with the isotropic hardening rule results from the interactions of dislocations on the slip ***,a modified nonlinear kinematic hardening rule and a rate-dependent flow rule at the slip system level are employed to improve the predictive capability of the model for ratchetting *** predictive ability of the developed model to uniaxial and mul-tiaxial ratchetting in macroscopic scale is verified by comparing with the experimental results of polycrystalline 316L stainless *** ratchetting in intra-granular scale which is obviously dependent on the crystallographic orientation and stress levels can be reasonably predicted by the proposed model.

关键词： Ratchetting Dislocation substructures Crystal plasticity Polycrystalline materials Constitutive model

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Nonlinear Analysis Of Thermo-Deformation-Polarization-Carrier Coupling Response of Piezoelectric Semiconductor Plates

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SSRN 2024年

作者： Xiao, Zhengguang Liu, Jinxi Zhang, Chunli Chen, Weiqiu Department of Engineering Mechanics Zhejiang University Hangzhou310027 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Huanjiang Laboratory Zhuji311816 China Faculty of Mechanical Engineering & Mechanics Ningbo University Ningbo315211 China

We present two-dimensional (2-D) thermo-deformation-polarization-carrier (TDPC) coupling equations for piezoelectric semiconductor (PS) thin plates incorporating both geometric and physical nonlinearities. To do so, we assume that the in-plane displacements, electric potential, concentration of carriers, and temperature have a linear distribution while the out-plane displacement has a parabolic distribution along the thickness direction. The derived TDPC coupling plate model comprises the zeroth and first order equations, which can be used to analyze the respective in-plane extensional and out-of-plane flexural deformations of PS plates with nonlinear multi-field coupling. The effectiveness of the developed plate model is validated. Based on the derived 2-D TDPC coupling equations, the nonlinear multi-field coupling mechanical responses of PS plates under single local mechanical or thermal load and their combinations are investigated in detail. The controlling mechanism of the combined mechanical and thermal loads on the electric potential and electron concentration as well as the formation of a potential well in PS plates is also revealed. © 2024, The Authors. All rights reserved.

关键词： Polarization

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Experimental Study on Geogrid-Soil Interface Properties Based on Pullout Tests: A Case Study

SSRN

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SSRN 2024年

作者： Wang, Zhijie Zhang, Guowei Yang, Guangqing Qin, Yan Zhou, Shiguang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China China Railway Society Beijing100844 China

The geogrid-soil interaction, which is crucial to the safety and stability of reinforced soil structures, is affected by the parameters of soils and geogrids. To investigate the influence of backfill and geogrid on their interface behavior of the reinforced soil retaining walls in Yichang section of Shanghai-Chongqing-Sichuan high-speed railway, a series of geogrid pullout tests were carried out. The development and evolution law of pullout force-pullout displacement curves and interface characteristics between geogrid and soil under various testing conditions were analyzed. The results showed that with increasing water content, the geogrid pullout force decreased under the same pullout displacement. The apparent friction angle of the geogrid-soil interface showed a slowly increasing trend with increasing water content. The variation of the apparent friction angle ranged between 9.2° and 10.7°. The apparent cohesion, however, decreased rapidly with increasing water content. With increasing degree of compaction, the apparent friction angle and the apparent cohesion of the geogrid-soil interface gradually increased. The change of the apparent cohesion with the compaction degree was more significant. When the degree of compaction increased from 0.87 to 0.93, the apparent cohesion increased around 7 times. The tensile strength of geogrid has certain influence on its pullout force-pullout displacement relationship. High-strength geogrid could significantly improve the mechanical properties of the geogrid-soil interface. The investigation results can provide some reference for the design and construction of geogrid reinforced soil structures. © 2024, The Authors. All rights reserved.

关键词： Tensile strength

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A New Semi-active Control Strategy and Its Application in Railway Vehicles

A New Semi-active Control Strategy and Its Application in Ra...

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International Conference on Applied Nonlinear Dynamics, Vibration and Control, ICANDVC 2021

作者： Yiwei, Zhao Shaopu, Yang Yongqiang, Liu Yingying, Liao Pengfei, Liu State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Transportation Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

ISBN: (纸本)9789811659119

With the continuous improvement of high-speed railway train operation speed, the problems of train operation safety and wheel rail wear are increasingly prominent. Improving train safety and reducing wheel rail wear can reduce operation and maintenance costs and bring greater economic benefits. In this context, a new semi-active control strategy applied in a Magnetorheological damper (MRD) is proposed to improve train safety and reduce wheel rail wear. Firstly, the transmission characteristics of the vehicle are analyzed according to the lateral vibration model of one quarter of two degrees of freedom. Then, the co-simulation model of Universal Mechanism (UM) and MATLAB is established, and the proposed control strategy is applied to the model to study its impact on the dynamic performance of the train. At the same time, the paper analyzes the influence of the control strategy on the dynamic performance of the train under different wearing levels. The results show that the control strategy can reduce the derailment coefficient of the train and the lateral force of the wheel axle, and improve the safety of the train greatly. At the same time, the wheel rail wear is reduced, the wheel wear degree is reduced, and the lathing cycle is prolonged. In addition, the control strategy can take into account the ride comfort of the train and maintain the good operation quality of the train. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： MATLAB

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Application Research of CEEMDAN in Early Fault Diagnosis of Rolling Bearing

Application Research of CEEMDAN in Early Fault Diagnosis of ...

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2021 IEEE International Conference on Sensing, Diagnostics, Prognostics, and Control, SDPC 2021

作者： Wang, Haiming Li, Qiang Yang, Shaopu Liu, Yongqiang School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing China Beijing Jiaotong University Beijing China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang China

ISBN: (纸本)9781665449762

In order to solve the difficulty of extracting early fault features of rolling bearings under strong background noise, a new fault diagnosis method for rolling bearings based on complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN). Firstly, in order to enhance the impact characteristics of signals, a set of IMF components were obtained by CEEMDAN. Then kurtosis was used as the evaluation index to select the effective component to obtain recombined signal. Finally, the envelope feature of the recombined signal was analyzed to judge the fault location. The validity and superiority of the proposed method are verified compared with other methods through the experimental analysis of the rolling bearings. © 2021 IEEE.

关键词： Failure analysis

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Design and Hydrodynamic Experiments of a Novel All-Speed Biomimetic Rudder-Controlled Autonomous Underwater Vehicle

Design and Hydrodynamic Experiments of a Novel All-Speed Bio...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Lan, Tianbo Ding, Jiang Li, Jingyu Xie, Fengran He, Kai Zuo, Qiyang School of Mechanical Engineering Guangxi University Guangxi Key Laboratory of Manufacturing System and Advanced Manufacturing Technology Nanning530004 China Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China Guangxi University State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Nanning530004 China School of Artificial Intelligence Shenzhen Polytechnic University Shenzhen518055 China

ISBN: (纸本)9781665481090

This paper presents a novel biomimetic rudder-controlled autonomous underwater vehicle (BRCAUV) that is capable of operating at all speed range (i.e. including high, medium, low, and even zero speeds) for both wide-area cruising and localized fine observation tasks. This AUV integrates a top rudder, a propeller, and two-degree-of-freedom (DOF) biomimetic rudder wings on both sides of the aft section, enabling it to perform various tasks in a single underwater operation. These tasks include wide-area cruising at medium to high speeds and fine observation at low and even zero speeds. The prototype is equipped with a propeller, a biomimetic dorsal fin, two pectoral fins(i.e. two-DOF biomimetic rudder wings), and a buoyancy regulation system. At medium to high speeds, the AUV utilizes a combination of the propeller and pectoral fin movements for ascent and descent. At low or zero speeds, the biomimetic pectoral fins are used for complex maneuvers such as buoyancy adjustment, roll, and pitch. This paper develops a dynamic model of the pectoral fins based on quasi-steady theory, elucidating the principles of low-speed steering. Experimental were carried out and the results validate the prototype's low-speed steering capabilities, so that new approaches were presented to enhance the maneuverability, multifunctionality, and practicality for underwater vehicles. © 2024 IEEE.

关键词： Buoyancy

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Sub-Preferential Rotational Wave Beaming in Structurally Rhombus Re-Entrant Honeycombs

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SSRN 2023年

作者： Zhu, Zhiwei Deng, Zichen State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical University Xi'An710072 China

Rotational waves frequently manifest in micro-structured materials and are often coupled with classical shear or longitudinal wave modes. In this study, a distinctive isolated optical branch, exhibiting very high polarization index related to joint rotation motion, is found in dispersion diagram of elastic wave propagation in structurally rhombus re-entrant honeycomb (SSRH). Through an analysis of group velocity, we further explore the wave beaming of the rotational wave propagation within the SRRH, and intriguingly, observe the emergence of sub-preferential wave beaming occurring along the short diagonal directions. This dynamic anisotropic phenomenon stems from the intricate interplay between wave frequency and structural topology. To elucidate the underlying dynamic anisotropy of rotational waves, we propose a simple rigid-spring model and derive an anisotropic coefficient that precisely captures the intricate frequency-structure coupling behavior. The obtained anisotropic coefficient unveils the formation of sub-preferential directions of the rotational wave within the SRRH. Our findings transcend the elucidation of dynamic anisotropy in lattice materials, extending to practical implications encompassing the manipulation of elastic wave propagation and the design of waveguides. © 2023, The Authors. All rights reserved.

关键词： Anisotropy

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Problems and Corrections of Classical Mathematical Model for Piecewise Linear system

SSRN

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SSRN 2024年

作者： Shen, Yongjun Zhang, Ruiliang Han, Dong Liu, Xiaoyan School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Electrical and Information Engineering Hebei Jiaotong Vocational and Technical College Shijiazhuang050035 China

Due to the existence of gap or backlash, many mechanical systems can be simplified into piecewise linear models. The dynamic study on mechanical system should be based on reliable mathematical model, so that it is very important to determine the contact point and separation point between the primary system and the auxiliary spring system (ASS) in the piecewise linear systems. In most existing literatures on piecewise linear systems, the contact point and the separation point of the mathematical model are fixed at the gap. But in this paper, it is found that the contact point and separation point actually change with the system parameters when the ASS contains damper, which implies the most existing mathematical model are incorrect. It is firstly demonstrated through numerical solution that the primary system will prematurely separate from the ASS before reaching the gap under harmonic excitation, which shows the incorrectness of the classical mathematical model. Then, based on the mechanical model and engineering practice, two corrected mathematical models are proposed. And the motions of the primary system and ASS after prematurely separation in the corrected models are studied. Finally, through comparison of the contact point, separation point, amplitude-frequency curves and motion state between the corrected models and the classical mathematical model, it can be concluded that the corrected models are more reasonable. And the comparisons with the experimental data implies that the corrected models can better reflect the engineering practice. These results will be helpful to the study and design of the piecewise linear system. © 2024, The Authors. All rights reserved.

关键词： Piecewise linear techniques

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Synthesis and Performance Characterization of a Low Adsorption Clay-resistant Polycarboxylate Superplasticizer

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Journal of Wuhan University of Technology(Materials Science) 2021年第3期36卷 446-455页

作者： ZHANG Ying WANG Pengshuo SUN Guowen YANG Jianming GAO Rui School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Civil Engineer-ing Yancheng Institute of TechnologyYancheng 224051China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China Heibei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang Tiedao UniversityShijiazhuang050043China

A low adsorption clay-resistant polycarboxylate superplasticizer(KN-PC)was synthesized using acrylic acid and isopentenol polyoxyethylene ether as the main reaction *** structural characterization and clay-resistant mechanism of the KN-PC were explored using Fourier transform infrared spectroscopy and X-ray diffraction,and the effect of the KN-PC on the performance of composite paste with various montmorillonite(MMT)contents was *** with ordinary polycarboxylate superplasticizer(PC),the KN-PC has a low sensitivity to the *** the action of the MMT,the adsorption dosage of the KN-PC on the MMT is much smaller than that of the PC.

关键词： polycarboxylate superplasticizer clay-resistant montmorillonite performance synthesis

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