检索结果-内蒙古大学图书馆

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

来源：评论

学校读者我要写书评

暂无评论

Love Waves in a Piezoelectric Semiconductor Thin Film on an Elastic Dielectric Half-Space

引用

固体力学学报（英文版） 2023年第1期36卷 45-54页

作者： Ru Tian Guoquan Nie Jinxi Liu Ernian Pan Yuesheng Wang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Mathematics and Physics Shijiazhuang Tiedao UniversityShijiazhuang 050043China 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 State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Engineering and Institute of Pioneer Semiconductor Innovation National Yang Ming Chiao Tung UniversityTaiwanChina Department of Mechanics Beijing Jiaotong UniversityBeijing 100044China

In this paper,Love waves propagating in a piezoelectric semiconductor(PSC)layered structure are investigated,where a PSC thin film is perfectly bonded on an elastic dielectric *** dispersion equations are derived *** influence of semiconducting properties on the propagation characteristics is examined in *** results show that the semiconducting effect reduces the propagation speed,and that the Love waves can propagate with a speed slightly higher than the shear wave speed of the elastic dielectric *** wave speed and attenuation significantly depend on the steady-state carrier density and the thickness of the PSC thin *** is also found that when the horizontal biasing electric field is larger than the critical value(corresponding to the zero attenuation),the wave amplitude is *** findings are useful for the analysis and design of various surface wave devices made of PSC.

关键词： Love wave Piezoelectric semiconductor Layered structure Dispersion Attenuation

来源：评论

学校读者我要写书评

暂无评论

Dynamic crushing behavior and energy absorption of hybrid auxetic metamaterial inspired by Islamic motif art

引用

Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 345-362页

作者： Ruilan TIAN Huaitong GUAN Xuhao LU Xiaolong ZHANG Huanan HAO Wenjie FENG Guanglei ZHANG Department of Engineering Mechanics Hebei Key Laboratory of Mechanics of Intelligent Materials and StructuresShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Auxetic honeycomb structures are promising metamaterials with outstanding mechanical properties,and can be potentially used in energy absorption *** this study,a novel modified re-entrant hybrid auxetic metamaterial inspired by Islamic motif art is designed by integrating four-pointed double re-entrant motifs with symmetric semi-hexagonal unit cells to achieve a high energy absorption capacity(EAC).Theoretical analyses and numerical simulations are performed to examine the dynamic crushing behavior of the four-pointed double re-entrant combined structure(FDRCS).The developed finite element models(FEMs)are validated by the experiments under quasi-static *** deformation mode and stress-strain curves are further studied under low,medium,and high crushing *** theoretically predicted plateau stress of the FDRCS under different crushing velocities is consistent with the numerical simulation *** crushing stress and the EAC of the FDRCS are influenced by the geometric parameters and crushing *** FDRCS exhibits a negative Poisson's ratio(NPR),owing to the four-point re-entrant structure(RES).Moreover,the specific energy absorption(SEA)of these structures is higher than that of nonauxetic hexagonal and auxetic re-entrant structures,owing to the generation of more plastic hinges that dissipate more energy during dynamic crushing.

关键词： re-entrant honeycomb auxetic hybrid metamaterial energy-absorption dynamic crushing

来源：评论

学校读者我要写书评

暂无评论

Research on hunting stability and bifurcation characteristics of nonlinear stochastic wheelset system

引用

Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 431-446页

作者： Peng WANG Shaopu YANG Yongqiang LIU Pengfei LIU Xing ZHANG Yiwei ZHAO State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Traffic and Transportation Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

A stochastic wheelset model with a nonlinear wheel-rail contact relationship is established to investigate the stochastic stability and stochastic bifurcation of the wheelset system with the consideration of the stochastic parametric excitations of equivalent conicity and suspension *** wheelset is systematized into a onedimensional(1D)diffusion process by using the stochastic average method,the behavior of the singular boundary is analyzed to determine the hunting stability condition of the wheelset system,and the critical speed of stochastic bifurcation is *** stationary probability density and joint probability density are derived *** on the topological structure change of the probability density function,the stochastic Hopf bifurcation form and bifurcation condition of the wheelset system are *** effects of stochastic factors on the hunting stability and bifurcation characteristics are analyzed,and the simulation results verify the correctness of the theoretical *** results reveal that the boundary behavior of the diffusion process determines the hunting stability of the stochastic wheelset system,and the left boundary characteristic value cL=1 is the critical state of hunting ***,stochastic D-bifurcation and P-bifurcation will appear in the wheelset system,and the critical speeds of the two kinds of stochastic bifurcation decrease with the increase in the stochastic parametric excitation intensity.

关键词： stochastic wheelset system stochastic average method singular boundary hunting stability stochastic Hopf bifurcation

来源：评论

学校读者我要写书评

暂无评论

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

Rock Mechanics Bulletin

引用

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

来源：评论

学校读者我要写书评

暂无评论

Defect Analysis and Innovation Design of Synchronizer for Clutchless Automatic mechanical Transmission

引用

Chinese Journal of mechanical engineering 2022年第1期35卷 238-254页

作者： Lipeng Zhang Yunao Peng Haojie Yang Shaohua Li Hebei Key Laboratory of Special Delivery Equipment Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The synchronizer is a key component of automatic mechanical transmission(AMT)equipped in electric vehicles,but the inertial lock-ring synchronizer(ILRS)commonly used there is not suitable especially for pure electric vehicles without a clutch because of big shift *** make the shifting process rapid and smooth,a new synchronizer named pressure-controllable friction ring synchronizer(PCFRS)was ***,the inevitable shortcoming of ILRS was verified by simulation and ***,the mechanical characteristics and advantages of the new synchronizer over ILRS were ***,the formulations describing the dynamic transmission based on the working mechanism of the PCFRS were ***,the shifting simulation results with PCFRS and ILRS based on the same operating conditions were compared and *** research shows that the PCFRS can meet the main shifting evaluation index of an AMT without complex control methods,as well as it takes only 0.2406 s to finish the comfortable and zero-speed-difference *** shifting quality of PCFRS is better than that of the *** lays a foundation for using the new synchronizer as a part of clutchless AMTs equipped in pure electric vehicles.

关键词： Electric vehicle Clutchless automatic mechanical transmission Inertial lock-ring synchronizer Pressure-controllable friction ring synchronizer mechanical characteristics Shifting quality

来源：评论

学校读者我要写书评

暂无评论

Research on the application of the parameter freezing precise exponential integrator in vehicle-road coupling vibration

引用

Applied Mathematics and Mechanics(English Edition) 2025年第2期46卷 373-390页

作者： Yu ZHANG Chao ZHANG Shaohua LI Shaopu YANG State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Research Center of the Basic Discipline Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The vehicle-road coupling dynamics problem is a prominent issue in transportation,drawing significant attention in recent *** dynamic equations are characterized by high-dimensionality,coupling,and time-varying dynamics,making the exact solutions challenging to *** a result,numerical integration methods are typically ***,conventional methods often suffer from low computational *** address this,this paper explores the application of the parameter freezing precise exponential integrator to vehicle-road coupling *** model accounts for road roughness irregularities,incorporating all terms unrelated to the linear part into the algorithm's inhomogeneous *** general construction process of the algorithm is *** validity of numerical results is verified through approximate analytical solutions(AASs),and the advantages of this method over traditional numerical integration methods are *** parameter freezing precise exponential integrator schemes are constructed based on the Runge-Kutta framework,with the fourth-order four-stage scheme identified as the optimal *** study indicates that this method can quickly and accurately capture the dynamic system's vibration response,offering a new,efficient approach for numerical studies of high-dimensional vehicle-road coupling systems.

关键词： vehicle-road coupled dynamics dynamic response parameter freezing precise exponential integrator Newmark-βintegration

来源：评论

学校读者我要写书评

暂无评论

IRT-diffusion: combined denoising diffusion probabilistic models with thermal signal processing methods for automated defect detection in composites using infrared thermography

IRT-diffusion: combined denoising diffusion probabilistic mo...

引用

2024 International Conference on Optical and Photonic engineering, icOPEN 2024

作者： Wei, Yanjie Zhang, Yuhang Xiao, Yao Gu, Xiaohui State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Engineering Mechanics Shijiazhuang Tiedao University Shijiazhuang050043 China

ISBN: (数字)9781510688117

ISBN: (纸本)9781510688100

Infrared thermography (IRT) is a reliable method for detecting defects in composites with advantages of full field, non-contact, easy operation and good visualization. Nevertheless, interpretation by experts is required to distinguish between defective and sound regions in the practical evaluation of defects, which limits the industrial applications of infrared thermography. In this study, a denoising diffusion probabilistic model (DDPM) framework named IRT-Diffusion is proposed to automatically segment defective regions in thermal images. IRT-Diffusion can reconstruct a defect segmentation image from a noisy image with standard Gaussian distribution by iteratively performing multiple denoising operations. Detection results from various traditional thermal signal processing methods are employed as input for the conditional noise predictor of IRT-Diffusion to generate more accurate defect segmentation results. The core innovation of this study is that the state-of-the-art generative model is first introduced and designed for defect identification in composites using infrared thermography. To assess the performance of IRT-Diffusion, experiments were conducted on several composites panels and compared with conditional variational autoencoder (CVAE) and conditional generative adversarial network (CGAN). The results demonstrate that the proposed method achieves superior quantitative metrics and effectively extracts defective regions. © 2025 SPIE.

关键词： Image segmentation

来源：评论

学校读者我要写书评

暂无评论

Determination of defect size for composites using derivative images in pulse thermography

Determination of defect size for composites using derivative...

引用

2024 International Conference on Optical and Photonic engineering, icOPEN 2024

作者： Wei, Yanjie Lu, Jiashuo Xiao, Yao Gu, Xiaohui State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Engineering Mechanics Shijiazhuang Tiedao University Shijiazhuang050043 China

ISBN: (数字)9781510688117

ISBN: (纸本)9781510688100

Pulse thermography is a reliable method for detecting defects in composites with advantages of full field, non-contact and easy operation. However, the size determination of subsurface defects with low width-to-depth ratios using pulsed thermography is a challenging task due to the blurred defect edges in infrared thermal images caused by lateral heat diffusion. The present study explores the ability of time derivative images of infrared thermography to predict defect size. 2D thermal conduction of pulse thermography based on the virtual heat source method was analyzed to compare the temperature profile and derivative profile of defects along the diameter direction, and a size prediction method based on the derivative profile is proposed. The feasibility of the proposed method was evaluated by measuring the dimensions of the flat-bottomed holes in the composite panels. The experimental results demonstrated that the size inversion method based on derivative images brings an improvement in measuring accuracy for defects. Additionally, the influences of cooling time, defect depth, defect size and thermal properties of the material on the measurement of defect dimension are also discussed. © 2025 SPIE.

关键词： Thermography (imaging)

来源：评论

学校读者我要写书评

暂无评论

A Novel Method for Repairing Missing Data of Bearing Vibration Signals Based on Compressed Sensing 2nd

A Novel Method for Repairing Missing Data of Bearing Vibrati...

引用

2nd International Conference of mechanical system Dynamics, ICMSD 2023

作者： Wang, Haiming Liu, Yongqiang Yang, Shaopu Li, Qiang School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing010044 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

ISBN: (纸本)9789819980475

The theory of compressed sensing is introduced to solve the repairing of missing data collected in PHM monitoring. An improved measurement matrix is proposed to optimize the conventional measurement matrix to increase the uncorrelation between the observation matrix and the sparse basis. Then a sparse representation of the vibration signal through discrete cosine transform (DCT) is utilized to sparse the noisy vibration signal. Finally, the orthogonal matching pursuit (OMP) algorithm is employed to reconstruct the missing signal. The method validation results show that the signal repaired by the proposed method agrees well with the original signal in the time domain, and the signal reconstructed by the optimized observation matrix has higher accuracy than the signal reconstructed by the initial observation matrix. Under different missing rates, the reconstruction error of the proposed method is smaller than other comparison methods. This shows the effectiveness and advantages of the proposed missing data recovery method. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Compressed sensing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：