检索结果-南通市图书馆

Numerical Exploration of Asymmetrical Impact Dynamics: Unveiling Nonlinearities in Collision Problems and Resilience of Reinforced Concrete Structures

引用

Structural Durability & Health Monitoring 2024年第3期18卷 223-254页

作者： AL-Bukhaiti Khalil Yanhui Liu Shichun Zhao Daguang Han School of Civil Engineering Southwest Jiaotong UniversityChengdu610031China Faculty of Civil Engineering Southeast UniversityNanjingChina

This study provides a comprehensive analysis of collision and impact problems’ numerical solutions, focusing ongeometric, contact, and material nonlinearities, all essential in solving large deformation problems during a collision.The initial discussion revolves around the stress and strain of large deformation during a collision, followedby explanations of the fundamental finite element solution method for addressing such issues. The hourglassmode’s control methods, such as single-point reduced integration and contact-collision algorithms are detailedand implemented within the finite element framework. The paper further investigates the dynamic responseand failure modes of Reinforced Concrete (RC) members under asymmetrical impact using a 3D discrete modelin ABAQUS that treats steel bars and concrete connections as bond slips. The model’s validity was confirmedthrough comparisons with the node-sharing algorithm and system energy relations. Experimental parameterswere varied, including the rigid hammer’s mass and initial velocity, concrete strength, and longitudinal and stirrupreinforcement ratios. Findings indicated that increased hammer mass and velocity escalated RC member damage,while increased reinforcement ratios improved impact resistance. Contrarily, increased concrete strength did notsignificantly reduce lateral displacement when considering strain rate effects. The study also explores materialnonlinearity, examining different materials’ responses to collision-induced forces and stresses, demonstratedthrough an elastic rod impact case study. The paper proposes a damage criterion based on the residual axialload-bearing capacity for assessing damage under the asymmetrical impact, showing a correlation betweendamage degree hammer mass and initial velocity. The results, validated through comparison with theoreticaland analytical solutions, verify the ABAQUS program’s accuracy and reliability in analyzing impact problems,offering valuable insights into collision and impact problems’ nonlinearities and practic

关键词： Geometric nonlinearity contact nonlinearity material nonlinearity collision problems finite element method stress and strain damage criterion RC members asymmetrical impact

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Time-domain Spectral Finite Element Method for Wave Propagation Analysis in Structures with Breathing Cracks

引用

Acta Mechanica Solida Sinica 2020年第6期33卷 812-822页

作者： Zexing Yu Chao Xu Fei Du Shancheng Cao Liaiigxian Gu School of Astronautics Northwestern Polytechnic UniversityXVan 710072China

Guided waves are generally considered as a powerful approach for crack detection in structures,which are commonly investigated using the finite element method(FEM).However,the traditional FEM has many disadvantages in solving wave propagation due to the strict requirement of mesh density.To tackle this issue,this paper proposes an efficient time-domain spectral finite element method(SFEM)to analyze wave propagation in cracked structures,in which the breathing crack is modeled by definiiig the spectral gap element.Moreover,novel orthogonal polynomials and Gauss-Lobatto-Legendre quadrature rules are adopted to construct the spectral element.Meanwhile,a separable hard contact is utilized to simulate the breathing behavior.Finally,a comparison of the numerical results between the FEM and the SFEM is conducted to demonstrate the high efficiency and accuracy of the proposed method.Based on the developed SFEM,the nonlinear features of waves and influence of the incident mode are also studied in detail,which provides a helpful guide for a physical understanding of the wave propagation behavior in structures with breathing cracks.

关键词： Time-domain spectral finite element method contact nonlinearity Gap element Breathing crack

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A nonlinear equivalent circuit method for analysis of passive intermodulation of mesh reflectors

引用

Chinese Journal of Aeronautics 2014年第4期27卷 924-929页

作者： Jiang Jie Li Tuanjie Ma Xiaofei Wang Pei School of Electromechanical Engineering Xidian University Xi’an Institute of Space Radio Technology

Passive intermodulation（PIM） has gradually become a serious electromagnetic interference due to the development of high-power and high-sensitivity RF/microwave communication systems, especially large deployable mesh reflector antennas. This paper proposes a field-circuit coupling method to analyze the PIM level of mesh reflectors. With the existence of many metal–metal（MM） contacts in mesh reflectors, the contact nonlinearity becomes the main reason for PIM generation. To analyze these potential PIM sources, an equivalent circuit model including nonlinear components is constructed to model a single MM contact so that the transient current through the MM contact point induced by incident electromagnetic waves can be calculated. Taking the electric current as a new electromagnetic wave source, the far-field scattering can be obtained by the use of electromagnetic numerical methods or the communication link method. Finally, a comparison between simulation and experimental results is illustrated to verify the validity of the proposed method.

关键词： contact nonlinearity Equivalent circuit Mesh reflector Metal-metal contact Nonlinear distortion Passive intermodulation Scattering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental and numerical study on microcrack detection using contact nonlinear acoustics

引用

Frontiers of Structural and Civil Engineering 2009年第2期3卷 137-141页

作者： Xiaojia CHEN Yuanlin WANG School of Transportation Wuhan University of TechnologyWuhan 430063China

This paper introduces a non-classical nonlinear acoustic theory for microcrack detection in materials,comparing contact nonlinearity with material nonlinearity.The paper's main work concentrates on the experimental and numerical verification of the effectivity of contact nonlinear acoustic detection by using the contact nonlinear parameter fl',which can be represented by the ratio of the second-harmonic amplitude to the square of the firstharmonic amplitude.Both experiments and numerical tests are performed.The results show that fl'is sensitive to the initiation of microcracks and varies with the development of the microcracks.The numerical test illustrates the decline offl'when microcracks penetrate each other.

关键词： microcrack detection contact nonlinearity numerical analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

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：