检索结果-内蒙古大学图书馆

In-plane mechanical properties of a novel hybrid auxetic structure

SMART MATERIALS AND STRUCTURES 2022年第7期31卷 075003-075003页

作者： Fan, Peng Chen, Yu Xiong, Jian Hu, Hong Hong Kong Polytech Univ Inst Text & Clothing Hong Kong Peoples R China Harbin Inst Technol Ctr Composite Mat & Struct Harbin Peoples R China Xi An Jiao Tong Univ Dept Engn Mech State Key Lab Strength & Vibrat Mech Struct Soft Machines Lab Xian Peoples R China Jinan Univ Coll Packaging Engn Packaging Engn Inst Zhuhai Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

This paper presents a novel hybrid auxetic structure with enhanced mechanical properties, combining the re-entrant and double-arrowhead structures, based on the structural stretching-dominated deformation mechanism. The unit cell of the developed hybrid structure comprises an external quadrilateral frame and an internal arrowhead part. The theoretical analysis model for predicting its in-plane mechanical properties in the two principal directions is presented and verified by both numerical simulations and experimental measurements. On this basis, a parametric study on the in-plane mechanical properties of the hybrid structure is performed to optimize geometrical parameters. The results show that both the negative Poisson's ratio behavior and the elastic properties of the hybrid structure can be enhanced by increasing the length of the vertical wall or reducing the angle of the inclined wall in the internal arrowhead part. The hybrid structure, with the obvious difference in elastic properties between the two principle directions, can be obtained by individually adjusting the width of the hybrid unit cell, while the elastic properties in bothdirections can be improved by simultaneously reducing the length of the vertical wall and the width of the hybrid unit cell. In addition, compared with the re-entrant and double-arrowhead structures, the hybrid structure demonstrates higher elastic moduli and a wider range of Poisson's ratios from negative to positive. The study provides guidance for the optimized design of hybrid auxetic structures in practical applications.

关键词： auxetic structure negative Poisson's ratio mechanical properties

来源：评论

学校读者我要写书评

暂无评论

Study of Building Safety Monitoring by Using Cost-Effective MEMS Accelerometers for Rapid After-Earthquake Assessment with Missing Data

引用

SENSORS 2021年第21期21卷 7327页

作者： Lin, Jian-Fu Li, Xue-Yan Wang, Junfang Wang, Li-Xin Hu, Xing-Xing Liu, Jun-Xiang Shenzhen Univ Coll Civil & Transportat Engn MOE Key Lab Resilient Infrastruct Coastal Cities Shenzhen 518060 Peoples R China China Earthquake Adm Shenzhen Acad Disaster Prevent & Reduct Ctr Safety Monitoring Engn Struct Shenzhen 518003 Peoples R China Jinan Univ Sch Mech & Bldg Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China China Earthquake Adm Inst Geophys Beijing 100081 Peoples R China

Suffering from structural deterioration and natural disasters, the resilience of civil structures in the face of extreme loadings inevitably drops, which may lead to catastrophic structural failure and presents great threats to public safety. Earthquake-induced extreme loading is one of the major reasons behind the structural failure of buildings. However, many buildings in earthquake-prone areas of China lack safety monitoring, and prevalent structural health monitoring systems are generally very expensive and complicated for extensive applications. To facilitate cost-effective building-safety monitoring, this study investigates a method using cost-effective MEMS accelerometers for buildings' rapid after-earthquake assessment. First, a parameter analysis of a cost-effective MEMS sensor is conducted to confirm its suitability for building-safety monitoring. Second, different from the existing investigations that tend to use a simplified building model or small-scaled frame structure excited by strong motions in laboratories, this study selects an in-service public building located in a typical earthquake-prone area after an analysis of earthquake risk in China. The building is instrumented with the selected cost-effective MEMS accelerometers, characterized by a low noise level and the capability to capture low-frequency small-amplitude dynamic responses. Furthermore, a rapid after-earthquake assessment scheme is proposed, which systematically includes fast missing data reconstruction, displacement response estimation based on an acceleration response integral, and safety assessment based on the maximum displacement and maximum inter-story drift ratio. Finally, the proposed method is successfully applied to a building-safety assessment by using earthquake-induced building responses suffering from missing data. This study is conducive to the extensive engineering application of MEMS-based cost-effective building monitoring and rapid after-earthquake assessment.

关键词： cost-effective MEMS accelerometer building safety monitoring missing data reconstruction structural health monitoring after-earthquake assessment

来源：评论

学校读者我要写书评

暂无评论

Design and simulation of ultra-thin and high-efficiency silicon-based trichromatic PIN photodiode arrays for visible light communication

引用

OPTICS COMMUNICATIONS 2020年 475卷 126296-126296页

作者： Gao, Dan Zhang, Jun Wang, Fan Liang, Jingqiu Wang, Weibiao Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Jinan Univ Dept Optoelect Engn Guangzhou 510632 Peoples R China Jinan Univ Guangdong Prov Key Lab Opt Fiber Sensing & Commun Guangzhou 510632 Peoples R China Jinan Univ Key Lab Optoelect Informat & Sensing Technol Guan Guangzhou 510632 Peoples R China Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys State Key Lab Appl Opt Changchun 130033 Jilin Peoples R China

Visible light communication offers abundant spectrum resources, which can alleviate the current shortage of wireless communication spectrum resources, and the security of the system is very reliable. In this study, a new photodiode (PD) array with micro-nano optical structure is designed and shown to effectively improve the absorption efficiency of PDs to blue, green, and red light. The absorption efficiency of blue, green, and red light at the central wavelength reached 96.8%, 97.5% and 98.6%, respectively, thus demonstrating the improved quantum efficiency of the device. Moreover, three color PDs are integrated into an ultra-thin silicon-on-insulator structure, increasing the integration and response speed of the device. The ultra-thin structure of the PD increases the response bandwidth up to the GHz level.

关键词： Array Photodiode Subwavelength structure Nanostructure

来源：评论

学校读者我要写书评

暂无评论

Identification of external forces via truncated response sparse decomposition under unknown initial conditions

引用

ADVANCES IN STRUCTURAL engineering 2019年第15期22卷 3161-3175页

作者： Pan, Chudong Yu, Ling Guangzhou Univ Sch Civil Engn Guangzhou Guangdong Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

When structural dynamic design for smart control and health monitoring is executed, imposed excitations on structures are one of most important issues in structural engineering. Identification of structural excitations, such as force reconstruction, moving force identification, and so on, has drawn increasing attentions in the last decades. Assumption of known initial conditions is a precondition for existing deterministic force reconstruction methods. However, initial conditions are often unknown and hard to be estimated. To address this problem, a novel truncated response sparse decomposition method is proposed for calculating the external forces under unknown initial conditions. The truncated response sparse decomposition involves two basic steps, that is, response sparse decomposition and force estimation. First, a collection of basis vectors is defined for expressing unknown forces. Unknown initial conditions are represented in modal space. Structural responses induced by both external forces and initial conditions are then normalized as potential response features to form an image dictionary, which is adapted to decompose the measured responses via sparse regularization. Second, the response features with lower decomposed amplitudes and small scaling factors are eliminated from the decomposed results. The remaining features are used for estimating the external forces. In order to assess the accuracy and the feasibility of the proposed force reconstruction method, some numerical simulations on a planar truss structure and a series of experimental studies are carried out. The illustrated results show the robustness and the applicability of the proposed method for addressing the force reconstruction problem under unknown initial conditions. Some related issues are discussed as well.

关键词： force reconstruction ill-condition problem sparse regularization truncated response sparse decomposition unknown initial conditions

来源：评论

学校读者我要写书评

暂无评论

Three-body problem - From Newton to supercomputer plus machine learning

引用

NEW ASTRONOMY 2022年第0期96卷

作者： Liao, Shijun Li, Xiaoming Yang, Yu State Key Lab Ocean Engn Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Ctr Marine Numer Expt Sch Naval Architecture Ocean & Civil Engn Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Sch Phys & Astron Shanghai 200240 Peoples R China Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Peoples R China MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

The famous three-body problem can be traced back to Newton in 1687, but quite few families of periodic orbits were found in 300 years thereafter. In this paper, we propose an effective approach and roadmap to numerically gain planar periodic orbits of three-body systems with arbitrary masses by means of machine learning based on an artificial neural network (ANN) model. Given any a known periodic orbit as a starting point, this approach can provide more and more periodic orbits (of the same family name) with variable masses, while the mass domain having periodic orbits becomes larger and larger, and the ANN model becomes wiser and wiser. Finally we have an ANN model trained by means of all obtained periodic orbits of the same family, which provides a convenient way to give accurate enough predictions of periodic orbits with arbitrary masses for physicists and astronomers. It suggests that the high-performance computer and artificial intelligence (including machine learning) should be the key to gain periodic orbits of the famous three-body problem.

关键词： Three-body problem Periodic orbit Machine learning Arbitrary mass of body

来源：评论

学校读者我要写书评

暂无评论

A novel preconditioned range restricted GMRES algorithm for moving force identification and its experimental validation

引用

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2021年 155卷 107635-107635页

作者： Chen, Zhen Qin, Lifeng Chan, Tommy H. T. Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun Zhengzhou 450045 Peoples R China Queensland Univ Technol QUT Sch Civil & Environm Engn Brisbane Qld 4000 Australia Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Moving force identification (MFI) is a widely concerned inverse problem in structural dynamics and well-known as intrinsically existing ill-posedness. With the help of Arnoldi process and Krylov subspace method, the generalized minimal residual (GMRES) method can be improved to a range restricted generalized minimal residual (RRGMRES) method. Furthermore, by introducing the smoothing-norm preconditioning, a preconditioned range restricted generalized minimal residual (PRRGMRES) method is proposed to provide a stable solution to the ill-posed dynamic force identification problem. Simulations show that the novel method has significant improvement when compared to the classic time domain method and the RRGMRES method. In addition, to show the effectiveness and advantages of the proposed method, the PRRGMRES method is also compared with a newly-proposed regularization method named the preconditioned least square QR-factorization (PLSQR) method. Simulation results show that the PRRGMRES method has much better robustness and higher computational efficiency than the PLSQR method especially in dealing with highly inaccurate measurement cases. Finally, the accuracy and efficiency of the PRRGMRES method is verified by experimental studies. The PRRGMRES method has good performance in both overcoming ill-posed problems and improving computational efficiency, which should be of the highest priority in adoption for MFI. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Preconditioned range restricted generalized minimal residual method Preconditioned least square QR-factorization method Smoothing-norm preconditioning Ill-posed problem

来源：评论

学校读者我要写书评

暂无评论

Sparse regularization-based damage detection in a bridge subjected to unknown moving forces

引用

JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING 2019年第3期9卷 425-438页

作者： Pan, Chudong Yu, Ling Guangzhou Univ Sch Civil Engn Guangzhou 510006 Guangdong Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Output-only structural damage detection (SDD) is an important issue in the field of structural health monitoring (SHM). As an attempt, this study aims to propose a sparse regularization-based method for detecting the structural damage using structural responses caused by unknown moving forces. First, a transmissibility matrix between two sensor sets is constructed using a known bridge model and least square-based moving force identification algorithm. Second, the measured responses are used as inputs to estimate the reconstructed responses with the help of the transmissibility matrix. Then, the damage detection procedure can be regarded as an optimization problem trying to find a possible damage vector, which makes the difference between the measured and reconstructed responses minimum. L-p-norm (0 < p <= 1) sparse regularization is adopted to improve the ill-conditioned SDD problem. To assess the feasibility of the proposed method, damaged bridges subjected to moving forces are taken as examples for numerical simulations. Differences between finite element model (FEM) used for model updating and the one applied to simulate the true damage conditions are considered. The illustrated results show that the proposed method can identify structural damages with a strong robustness. Some related issues, such as regularization parameters, finite element models, L-p-norm (0 < p <= 1) penalty terms, noise levels and damage patterns, are discussed as well.

关键词： Structural health monitoring (SHM) Structural damage detection (SDD) Sparse regularization Unknown moving force

来源：评论

学校读者我要写书评

暂无评论

STUDY ON THE PROPERTIES OF POLYURETHANE-CEMENT COMPOSITE (PUC)

引用

CIVIL engineering JOURNAL-STAVEBNI OBZOR 2021年第2期30卷 560-571页

作者： Zhang, Kexin Li, Dachao Qi, Tianyu Li, Yanfeng Xue, Xingwei Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Dadao West Guangzhou Peoples R China Shenyang Jianzhu Univ Sch Traff Engn 25 Hunnan Zhong Rd Shenyang Liaoning Peoples R China

In order to study the properties of polyurethane cement composite (PUC) material, this paper has carried out the tests of compressive resistance, flexural resistance, axial tension, bonding and acid and alkali corrosion resistance of the material. The average compressive strength of the material is 59.3 MPa, the average flexural strength is 41.5 MPa, and the average axial tensile strength is 31.0 MPa. The bonding strength between the material and concrete in axial tension is 3.56 MPa, and that between the material and concrete in bending is 3.16 MPa. The failure interface of the two bond tests is not on the bond surface, indicating that the polyurethane cement composite (PUC) material has good bonding property. The chemical corrosion resistance test of polyurethane cement material showed no visible change on the surface of the material, indicating good chemical corrosion resistance.

关键词： Polyurethane cement Mechanical property Acid and alkali resistance Adhesive property

来源：评论

学校读者我要写书评

暂无评论

Effect of viscoelasticity on interfacial stress transfer mechanism in the biocomposites: A theoretical study of viscoelastic shear lag model

引用

COMPOSITES PART B-engineering 2019年 164卷 297-308页

作者： Wu, Jiayu Yuan, Hong Li, Long-yuan Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Inst Appl Mech Guangzhou 510632 Guangdong Peoples R China Univ Plymouth Sch Engn Plymouth PL4 8AA Devon England

Biocomposite with regularly staggered alignment microstructure is frequently observed in natural biological tissues, and exhibits superior mechanical behavior. Owing to their viscoelastic nature, biocomposites exhibit stress rate-dependent stiffness function and mechanical behavior. In this paper, a linear viscoelastic shear lag model (SLM) is proposed to illustrate the micromechanical behavior of biocomposites under triangular loading pulse. Theoretical and numerical results are derived to predict the deformation and stress transfer between fibers and interfibrous matrix while the biocomposite is transiently stretched. The results from the analytical and numerical solutions demonstrate that how the fiber overlap length and loading rate affect the stress transfer and mechanical properties of biocomposites. The structure-property correlation is illustrated for viscoelastic biomaterials under transient loading, and existence of characteristic length of soft matter with viscoelastic property is involved in load transfer mechanism between the adjacent reinforcements in transient regime, which optimizes the load transfer mechanism between the adjacent reinforcements. Furthermore, we found that discontinuous fibril model could ensure large relative sliding deformation, helping dissipate energy, protecting fibril from overall damage, and achieving high ductility and high toughness, which can provide beneficial design strategies for engineering fiber reinforced composites.

关键词： Biocomposites Shear lag model Mechanics of composite interface Viscoelastic model Mechanical response

来源：评论

学校读者我要写书评

暂无评论

STUDY ON BONDING PROPERTY OF POLYURETHANE CEMENT (PUC) TO STEEL BAR

引用

CIVIL engineering JOURNAL-STAVEBNI OBZOR 2021年第3期30卷 658-670页

作者： Zhang, Kexin Li, Dachao Shen, Xinyuan Qi, Tianyu Xue, Xingwei Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Dadao West Guangzhou Guangdong Peoples R China Shenyang Jianzhu Univ Sch Traff Engn 25 Hunnan Zhong Rd Shenyang Liaoning Peoples R China

The pull-out test of the bar and PUC is carried out in this paper, the effects of protective layer thickness, reinforcement anchorage length, diameter and shape of reinforcement on bonding properties were studied. The results show that the bond strength between reinforcement and PUC material increases with the increase of the thickness of the protective layer but decreases with the increase of the anchorage length and diameter of reinforcement. The bond strength of bare round steel is significantly lower than that of ribbed steel, and the maximum bond strength is about 47.4% of ribbed steel. By analyzing the bond slip curve obtained from the pull-out test, the stress process of bond anchorage between reinforcement bar and PUC material is mainly summarized into three stages: the rising stage, the falling stage and the residual stage. The characteristics of the curve, the stress process and the failure mode of specimen at each stage are analyzed.

关键词： Polyurethane cement (PUC) material Steel bar Bond stress Pull-out test Bond-slip curve

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：