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Indentation behavior of a semi-infinite piezoelectric semiconductor under a rigid flat-ended cylindrical indenter

Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 649-662页

作者： Shijing GAO Lele ZHANG Jinxi LIU Guoquan NIE Weiqiu cHEN State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory for Mechanics of Intelligent Materials and Structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Computer Aided Design and Computer Graphics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

This paper theoretically studies the axisymmetric frictionless indentation of a transversely isotropic piezoelectric semiconductor(PSc)half-space subject to a rigid flatended cylindrical *** contact area and other surface of the PSc half-space are assumed to be electrically *** the Hankel integral transformation,the problem is reduced to the Fredholm integral equation of the second *** equation is solved numerically to obtain the indentation behaviors of the PSc half-space,mainly including the indentation force-depth relation and the electric potential-depth *** results show that the effect of the semiconductor property on the indentation responses is limited within a certain range of variation of the steady carrier *** dependence of indentation behavior on material properties is also analyzed by two different kinds of *** element simulations are conducted to verify the results calculated by the integral equation technique,and good agreement is demonstrated.

关键词： piezoelectric semiconductor(PSc) insulating indenter electromechanical response singular integral equation finite element simulation

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Predictive fatigue crack growth law of high-strength steels

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Journal of Materials Science & Technology 2022年第5期100卷 46-50页

作者： H.F.Li P.Zhang B.Wang Z.F.Zhang Laboratory of Fatigue and Fracture for Materials Shi-changxu Innovation Center for Advanced MaterialsChinese Academy of SciencesInstitute of Metal ResearchShenyang 110016China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The fatigue resistance of metallic materials is generally attributed to both strength and ***,these properties are mutually exclusive in most *** theories like Paris’law only provide some data correlation schemes rather than a predictive capability,which cannot satisfactorily guide the anti-fatigue *** this study,for the first time,the predictive fatigue crack growth rate law is proposed by considering the effects of both strength and ***,a quantitative criterion is established for judging the fatigue crack resistance of high-strength *** predictive law would provide a unique view to the quantitative anti-fatigue design of metallic materials.

关键词： Fatigue crack growth Strength and toughness Paris’law High-strength steels

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Effects of cavitation on vortex-induced vibration of a flexible circular cylinder simulated by fluid-structure interaction method

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Journal of Hydrodynamics 2022年第3期34卷 499-509页

作者： Zhi-jian Xiao Shi-hao Yang cao Yu Zhen Zhang Lei Sun Jiang Lai Yan-ping Huang Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China Nuclear Power Institute of China Chengdu610041China Beijing Electro-mechanical Engineering Institute Beijing100074China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China

To investigate the effects of the cavitation on the vortex-induced vibration,the flow and the vibration characteristics of a flexible circular cylinder in the non-cavitating and cavitating flows at Re=200 are simulated using a fluid-structure interaction(FSI)solver,developed in the OpenFOAM *** accuracy of the fluid-structure interaction solver is verified using the benchmark *** a freely vibrating circular cylinder,the characteristics of the vortex-induced vibration are determined at different frequency *** frequency lock-in is observed in both the cavitating flow and the non-cavitating flow,and the lock-in frequency range is larger in the cavitating flow with a smaller vibration *** the lock-in frequency range,due to the reduction of the fluid forces and the resonance effects at the dominant frequency,the vibration amplitude is decreased in the cavitating flow,as compared to the non-cavitating ***,the low-density vapor and the cavitation collapse weaken the constraints of the flow and the stability of the shedding vortices,respectively,making the flow around the circular cylinder more sensitive to the structural ***,the lock-in frequency range is larger in the cavitating flow.

关键词： Fluid-structure interaction(FSI) cavitation lock-in frequency vortex-induced vibrations OpenFOAM

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Mesh stiffness calculation and vibration analysis of the spur gear pair with tooth crack,considering the misalignment between the base and root circles

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International Journal of mechanical system Dynamics 2021年第1期1卷 143-156页

作者： Jingyu Hou Shaopu Yang Qiang Li Yongqiang Liu Jiujian Wang School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijingChina State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangChina School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuangChina State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangshaChina

An improved variable cross‐section cantilever beam model for evaluating the time‐varying mesh stiffness(TVMS)of the perfect gear tooth is developed in which the tooth number of driving gear is less than 42 and that of driven is more than *** TVMS obtained by the proposed method is compared with the result without considering the misalignment between the base circle and gear *** types of root crack models and changes inTVMS of 13‐crack levels are *** fault vibration characteristic of a single‐stage spur gear reducer with root crack is ana-lyzed and the correctness is qualitatively verified by the vibration signals of an experimental gearbox with crack or missing *** results presented in this paper are of great significance for a deep understanding of the possible causes of vibration and noise of gears and provide a theoretical foundation for the fault diagnosis of the gearbox.

关键词： backlash gear potential energy method time‐varying mesh stiffness(TVMS) tooth crack

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Damage effect and progressive failure mechanism of sandstone considering different flaw angles under dynamic loading

Rock Mechanics Bulletin

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Rock Mechanics Bulletin 2024年第1期3卷 81-96页

作者： Dongliang Ji Hui cheng Hongbao Zhao State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangChina Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao UniversityShijiazhuangChina School of Energy and Mining Engineering China University of Mining and Technology(Beijing)BeijingChina

In many engineering applications,it is essential to have information about rocks that inherently contain preexisting flaws under dynamic loading *** impact tests are conducted on samples with varying flaw angles using the split Hopkinson pressure bar(SHPB)test system and the Digital Image correlation system(DIc).The characteristics of the samples after dynamic loading,including dynamic strength,energy dissipation,and fractal fracture,are compared and *** the flaw angle increases,the peak stress and strain exhibit a typical V-shaped pattern,reaching the minimum value at 30,and the initial initiation position shifts from the flaw tips to the middle of the *** modes can be divided into three modes depending on the flaw *** progressive failure process,taking into account the heterogeneity of the rock,is demonstrated by developing an elastic damage constitutive model that uses dynamic compression and tensile tests to parameterize *** the flaw angle increases,the initial damage zone also moves from the flaw tips to the middle of the *** around the hole with redistributed stress are observed,and the failure mechanisms can be explained with the aid of strain energy density(SED).Using fracture mechanics,the analytical solution of stress around the flaw is provided,and the variation of crack initiation angle,stress distribution,and energy dissipation under different flaw angles is theoretically explained,which is in good agreement with the experimental and simulated results.

关键词： Dynamic loading Damage evolution constitutive model Flaw angle Energy dissipation

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Numerical investigation on the twisted wind-induced aeroelastic response of a square supertall building

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Journal of Fluids and structures 2025年 137卷

作者： Bowen YAN Qiaowen Ran Yangjin Yuan Hongyu Ren Xiao Li Xuhong Zhou Qingshan Yang Qingkuan Liu Key Laboratory of New Technology for Construction of Cities in Mountain Area (Ministry of Education) School of Civil Engineering Chongqing University Chongqing 400045 PR China Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Kowloon Hung Hom Hong Kong State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang 050043 PR China

The aerodynamic and aeroelastic characteristics of a square supertall building and the surrounding wind field are numerically analyzed, accounting for the influence of the twisted wind field (TWF). A two-way coupled fluid-structure-interaction (FSI) simulation, validated by the aeroelastic experiments conducted in both TWF and conventional wind field (cWF), is employed to fulfill this purpose. This study focuses on the effect of TWF on the vortex-induced vibration (VIV) response of the building and associated aerodynamic forces acting on the aeroelastic model. The results indicate that the fluctuating forces on the tall building are reduced significantly when it is immersed in TWF compared to those in cWF. In TWF, the spectral energy of the across-wind force is dispersed over a wider frequency range than that in the cWF. Furthermore, the aeroelastic response of the building in the TWF is restricted at the upper range of the reduced wind velocity, attributed to the disordered and twisted wake flow near the building. The findings from the present study can enhance the understanding of the VIV behavior of super-tall buildings under the effect of twisted winds.

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cause Analysis of Rail Abnormal corrugation on the cologne Egg Fastener Track in Metro Straight Section

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Zhendong ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis 2025年第2期45卷 240-247and408页

作者： Wang, Zhiqiang Lei, Zhenyu Tong, Fengzhuang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Shanghai201804 China

In order to study the rail abnormal corrugation on the cologne egg fastener track in the metro straight section, a two-dimensional numerical model reflecting the energy dissipation characteristics of the wheel-rail system is proposed. combined with field investigation and numerical calculation, the cause characteristics of rail corrugation are analyzed. The results show that with the increase of the proportion of longitudinal creep force, when the excitation is applied above the fastener, the longitudinal creep force has a greater effect on the occurrence probability and development trend of rail corrugation;when the excitation is applied in the middle of the fastener span, both the longitudinal and transverse creep force can promote the generation and development of rail corrugation in this case. In the process of increasing the proportion of longitudinal creep force, the sensitivity to the real part of the system dissipation energy gradually changes from wavelength sensitivity to velocity sensitivity;meantime, the wavelength remains constant at different speeds or shows a nonlinear relationship with the speed, indicating that sensitive speeds of corrugation wavelengths are different under different creep force conditions. The influence analysis of rail receptances shows that under different creep force conditions, the same characteristic frequency appears and is close to the passing frequency of measured corrugation, illustrating that the rail vertical receptance characteristic when the excitation is applied above the fastener is the main cause of the rail corrugation. © 2025 Nanjing University of Aeronautics an Astronautics. All rights reserved.

关键词： keyways

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Establishment of Dynamic Model for Axle Box Bearing of High-Speed Trains Under Variable Speed conditions

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chinese Journal of mechanical engineering 2022年第4期35卷 340-351页

作者： Yongqiang Liu Baosen Wang Bin Zhang Shaopu Yang School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Trafc and Transportation Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Engineering and Computing University of South CarolinaColumbiaSouth Carolina 29208USA State Key Laboratory of Mechanical Behavior and System Safety of Trafc Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

In this study,a dynamic model for the bearing rotor system of a high-speed train under variable speed conditions is *** contrast to previous studies,the contact stress is simplifed in the proposed model and the compensation balance excitation caused by the rotor mass eccentricity *** angle iteration method is used to overcome the challenge posed by the inability to determine the roller space position during bearing *** simulation results show that the model accurately describes the dynamics of bearings under varying speed profles that contain acceleration,deceleration,and speed oscillation *** order ratio spectrum of the bearing vibration signal indicates that both the single and multiple frequencies in the simulation results are consistent with the theoretical *** on bearings with outer and inner ring faults under various operating conditions are performed to verify the developed model.

关键词： Variable speed conditions High-speed train Bearing model Angle iteration Order ratio spectrum

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Low-light traffic Objects Detection for Automated Vehicles 6

Low-light Traffic Objects Detection for Automated Vehicles

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6th cAA International conference on Vehicular control and Intelligence, cVcI 2022

作者： Wang, Xuewei Wang, Dongmei Li, Siyuan Li, Shaohua Zeng, Pengtian Liang, Xiao Shijiazhuang Tiedao University State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (数字)9781665453745

ISBN: (纸本)9781665453745

The low-light condition brings huge challenges to the traffic object detection, limiting its application in complex scenarios such as the round-the-clock traffic monitoring and automatic driving. To address this issue, an accurate traffic object detection method in low-light conditions is proposed. First, the dark channel prior knowledge is utilized to restore the scene radiance via the transmission map and the estimation of the atmospheric light. Meanwhile, the grayscale is adjusted by adaptive gamma transformation to further improve the brightness of the image and reduce the impact of low-light conditions. Second, a LL4PH-Net framework equipped with preset anchors and detection branches is developed to detect low-light traffic objects. The performance of the algorithm is tested on the public BDD100K dataset. Experimental results show that compared with the SOTA methods, the proposed LL4PH-Net acquires the best detection mAP, the most lightweight model and a good time efficiency. It can effectively detect traffic objects even under low-light conditions. © 2022 IEEE.

关键词： Image enhancement

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Multi-field coupling and free vibration of a sandwiched functionally-graded piezoelectric semiconductor plate

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1351-1366页

作者： Xueqian FANG Qilin HE Hongwei MA changsong ZHU School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical *** multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron *** material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the *** total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s *** introducing the boundary conditions,the coupling physical fields are *** numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are *** is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of *** effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.

关键词： sandwiched piezoelectric semiconductor(PS)plate functionally-graded layer multi-field coupling free vibration Hamilton's principle

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