检索结果-内蒙古大学图书馆

TiB2- and Fe2P with nanotwins-reinforced Cu-based immiscible composites fabricated by selective laser melting: Formation mechanism and wear behavior

引用

JOURNAL OF ALLOYS AND COMPOUNDS 2021年 864卷 158716-158716页

作者： Xie, Min Wu, Changyi Zhou, Shengfeng Jin, Jianbo Zhao, Shuzhen Chen, Dongchu Tiangong Univ Sch Mat Sci & Engn Tianjin 300387 Peoples R China Hunan First Normal Univ Dept Educ Sci Changsha 410205 Hunan Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Jinan Univ Inst Adv Wear & Corros Resistance & Funct Mat Guangzhou 510632 Peoples R China Foshan Univ Sch Mat Sci & Energy Engn Foshan 52800 Guangdong Peoples R China

To restrain the collision and coarsening of Fe-rich droplets within supercooled Cu-Fe immiscible melt, the TiB2 particles as inoculants are introduced to produce the TiB2 and Fe2P with nanotwins-reinforced Cu-based immiscible composites by selective laser melting (SLM). The Cu-based immiscible composite with heterogeneous structure is characterized by nano-/micro-scale Fe2P particles and micron fibrous Fe2P dispersed within the epsilon-Cu matrix. Moreover, some nanotwinned Cu (nt-Cu) particles and a high density of nanotwins are embedded within these nano-scale Fe2P particles, whereas some irregular alpha-Fe precipitated within these fibrous Fe2P. The addition of TiB2 particles can refine the size of Fe2P and promote their homogeneous distribution within the epsilon-Cu matrix. As a result, the hardness and wear resistance of the TiB2 reinforced Cu-based immiscible composite are significantly improved by the combined strengthening mechanisms of twin boundaries (TBs) strengthening, refinement strengthening, dispersion strengthening and precipitation strengthening. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Selective laser melting Immiscible composite Wear behavior Liquid phase separation Nanoscale twins

来源：评论

学校读者我要写书评

暂无评论

Hybrid three-dimensional graphene fillers and graphite platelets to improve the thermal conductivity and wear performance of epoxy composites

引用

COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING 2019年 123卷 270-277页

作者： Zhou, Helezi Wang, Hongjian Du, Xusheng Mo, Youtian Yuan, Hong Liu, Hong-Yuan Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ Inst Adv Wear & Corros Resistant & Funct Mat Guangzhou 510632 Guangdong Peoples R China Univ Sydney Sch Aerosp Mech & Mechatron Engn J07 Sydney NSW 2006 Australia

Based on our recent work on the three-dimensional graphene fillers (3DGF) reinforced epoxy (EP) composite, here commercially available graphite platelets (GP) were incorporated together with 3DGF to modify EP in order to further improve the thermal conduction and wear resistance of the EP composites. Remarkably, only 0.14 vol % 3DGF was needed to enhance the thermal conduction of EP by 170%, in contrast with the fact that 37 times content of graphite fillers were required to achieve almost the same enhancement. Moreover, in the presence of both 5.38 vol% GP and 0.14 vol% 3DGF, the thermal conductivity of EP was further enhanced by 258%. Meanwhile, the tribological test results revealed the advantage of 3DGF over GP. The ternary EP composite modified with both 0.28 vol% of 3DGF and 5.38 vol% GP had much lower specific wear rate and coefficient of friction than those binary composites with either 3DGF or GP.

关键词： Hybrid Nanocomposites Thermal properties Wear

来源：评论

学校读者我要写书评

暂无评论

Experimental study of seismic performance of full-scale basalt FRP-recycled aggregate concrete-steel tubular columns

引用

THIN-WALLED STRUCTURES 2020年 151卷 106185-106185页

作者： Zeng, Lan Li, Lijuan Xiao, Peijie Zeng, Junjie Liu, Feng Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Guangdong Univ Technol Sch Civil & Transportat Engn Guangzhou 510006 Peoples R China Guangdong Planning & Designing Inst Telecommun Co Guangzhou 510630 Guangdong Peoples R China

Hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs) have received extensive attention in the research community over the past decade. Generally, a DSTC consists of an inner steel tube and an outer FRP tube, with the space between them filled with natural aggregate concrete (NAC). This paper studied a new form of hybrid FRP-recycled aggregate concrete (RAC)-steel tubular column (FRSTC) in which the outer FRP tube was made of environmental-friendly basalt fibers and the concrete was made of recycled coarse aggregates (RCAs). Quasi-static tests of five full-scale basalt FRSTCs were conducted to gain an improved understanding of the behavior of FRSTCs, and to enable further application potentiality of FRSTCs in earthquake-prone areas. Three key column parameters, including RCA replacement percentages, axial load ratios, and steel reinforcement ratios were carefully designed to clarify their influence on the performance of FRSTCs under combined axial compression and cyclic lateral loading. The test results, including the hysteretic loops, skeleton curves, curvature and strain distributions, ductility characterization, energy dissipation capacity, stiffness and strength degradation, and cumulative damage, are presented and discussed. The experimental results show that the RCA replacement percentage has little impact on the seismic performance of FRSTCs, while the effect of the axial load ratio is significant. The bearing capacity and energy dissipation of FRSTCs can be superior to those of DSTCs with NAC.

关键词： Basalt fiber-reinforced polymer (BFRP) tube Recycled aggregate concrete (RAC) Steel tube Composite column Seismic behavior Quasi-static test

来源：评论

学校读者我要写书评

暂无评论

EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES OF POLYURETHANE POWDER COMPOSITES

引用

CIVIL engineering JOURNAL-STAVEBNI OBZOR 2021年第4期30卷 877-888页

作者： Zhang, Kexin Li, Dachao Shen, Xinyuan Xue, Xingwei Gu, Dandan Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Dadao West Guangzhou Guangdong Peoples R China Shenyang Jianzhu Univ Sch Traff Engn Dept Bridge 25 Hunnan Middle Rd Shenyang Peoples R China Shenyang Inst Technol Sch Energy & Hydraul Engn East Sect Binhe Rd Shenfu New Dist Liaoning Peoples R China

In recent years, there have been cases of strengthening bridge structures with polyurethane cement mortar. To further explore the properties of polyurethane materials, the effects of emery, lime, quartz sand and cement on the mechanical properties of polyurethane powder composites are studied by three-point flexural test. In the flexural test, the polyurethane cement composite formed a control group by changing the content of polyester polyol. The flexural strength and ductility are improved to a certain extent due to the addition of polyester polyol. The average flexural strength of other polyurethane powder composites such as polyurethane emery test block is 45.1 MPa and the corresponding strain is 6203 mu epsilon, the average flexural strength of polyurethane lime test block is 33.4 MPa and the corresponding strain is 6470 mu epsilon, the average flexural strength of polyurethane quartz sand test block is 49.23 MPa and the corresponding strain is 7521 mu epsilon. The results show that the flexural strength of polyurethane emery material and polyurethane quartz sand material is higher than that of polyurethane cement, which can be used to replace cement to a certain extent to reduce the cost of polyurethane composite material.

关键词： Polyurethane cement (PUC) material Mechanics performance tests Polyurethane powder composites Constitutive relation

来源：评论

学校读者我要写书评

暂无评论

Comparison of regularization methods for moving force identification with ill-posed problems

引用

JOURNAL OF SOUND AND VIBRATION 2020年 478卷 115349-000页

作者： Chen, Zhen 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 Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Four new methods have been developed to overcome the ill-posed problems inherently existing in moving force identification (MFI) in previous studies. This paper is an extension of the work to evaluate the overall performance of these presented methods by numerical simulations and experiment verifications in laboratory. A simply-supported bridge and two types of moving forces are adopted to evaluate the identification accuracy and ill-posed immunity of these new approaches. Bending moment and acceleration responses are measured when the time-varying forces moving across the bridge deck at constant speed. Numerical simulations of both uniaxial and biaxial forces include 12 cases, which are used to compare the identification accuracy and ill-posed immunity of these methods in detail. Finally, a hinge supported steel beam model and a vehicle model were designed and fabricated in laboratory. Then a series of experimental studies on MFI with these four methods are performed in laboratory. Both numerical and experimental results show that these four approaches can accurately identify moving forces with strong robustness and ill-posed immunity. Moreover, the truncated generalized singular value decomposition (TGSVD) method has higher identification accuracy than the piecewise polynomial truncated singular value decomposition (PP-TSVD) method, and the modified preconditioned conjugate gradient (M-PCG) method has higher identification efficiency than the pre-conditioned least square QR-factorization (PLSQR) method. To summarize, if the first goal in MFI is to improve the identification accuracy, the TGSVD method is recommended due to its high identification accuracy and stability in different cases. If the first goal in MFI is to improve the identification efficiency, the M-PCG method is recommended due to its high identification efficiency and easy to determine the optimal number of iterations. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Ill-posed immunity Identification accuracy Identification efficiency Numerical simulations Experiment verifications Regularization

来源：评论

学校读者我要写书评

暂无评论

Analysis of Vibration Monitoring Data of Flexible Suspension Lifting Structure Based on Time-Varying Theory

引用

SENSORS 2020年第22期20卷 6586.-6586.页

作者： Peng, Qifeng Xu, Peng Yuan, Hong Ma, Haixia Xue, Jianghong He, Zhenya Li, Shanqing Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou 510632 Peoples R China South China Univ Technol Guangzhou Coll Sch Elect Engn Guangzhou 510800 Peoples R China South China Univ Technol Guangdong Prov Key Lab Precis Equipment & Mfg Tec Guangzhou 510640 Peoples R China

An elevator is a typical flexible lifting machine. In order to monitor the vibration of elevator structure, the vibration characteristics of an elevator with a traction ratio of 1:1 has been tested experimentally. Sensors were arranged on the platform frame, car roof, and hoist rope to test the vibrations of the elevator in both ascending and descending conditions. The transverse, longitudinal, and coupled transverse-longitudinal vibrations were compared and analyzed. Further, the short-time Fourier transform (STFT) method was used to examine the power spectral density (PSD) of the test results, and the main frequency distribution and influencing factors of the vibration of elevator components were investigated. The results revealed that the transverse and longitudinal vibrations of the platform frame were low-frequency vibrations, which was attributed to the elastic interaction between the platform frame and the car frame. The form and amplitude of longitudinal vibration of the car frame were basically consistent with those of the platform frame, but PSD of the transverse vibration had an obvious peak in the high-frequency region. The transverse and longitudinal vibration frequencies of the hoist rope were higher. Furthermore, the peak PSD value of transverse vibration of the hoist rope was 421 times larger than that of the car frame, so a small disturbance at the end of the rope could lead to a huge disturbance in the center of the rope. Overall, this study provides useful insights on designing an elevator monitoring sensor and relevant data processing.

关键词： machine dynamics non-linear vibration random vibration sensors and actuators structural dynamics and control

来源：评论

学校读者我要写书评

暂无评论

Identification of vehicle axle loads from bridge responses using preconditioned least square QR-factorization algorithm

引用

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2019年 128卷 479-496页

作者： Chen, Zhen Chan, Tommy H. T. Nguyen, Andy Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun 36 Beihuan Rd Zhengzhou 450045 Henan Peoples R China QUT Sch Civil Engn & Built Environm Brisbane Qld 4000 Australia USQ Sch Civil Engn Surveying Springfield Cent 4300 Australia Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

This paper develops a novel method for moving force identification (MFI) called preconditioned least square QR-factorization (PLSQR) method. The algorithm seeks to reduce the impact of identification errors caused by unknown noise. The biaxial moving forces travel on a simply supported bridge at three different speeds is used to generate numerical simulations to assess the effectiveness and applicability of the algorithm. Results indicate that the method is more robust towards ill-posed problem and has higher identification precision than the conventional time domain method (TDM). In addition, the robustness and ill-posed immunity of PLSQR are directly affected by two kinds of regularization parameters, namely, number of iterations j and regularization matrix L. Compared with the standard form of least square QR-factorization (LSQR), i.e., the regularization matrix L being the identity matrix I-n, the PLSQR with the optimal number of iterations j and regularization matrix L has many advantages on MFI and it is more suitable for field trials due to better adaptability with type of sensors and number of sensors. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Preconditioned least square QR-factorization Time domain method Regularization parameter Preconditioner

来源：评论

学校读者我要写书评

暂无评论

Structural damage detection via adaptive dictionary learning and sparse representation of measured acceleration responses

引用

MEASUREMENT 2018年 128卷 377-387页

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

Extracting damage-sensitive features from measured acceleration responses is still a big challenge in structural damage detection (SDD). In order to obtain the sparse representation of acceleration responses for damage identification, two dictionary learning methods and a damage indicator based on the change in mean sparsity (CMS) have been proposed in this paper. The first dictionary is empirical mode decomposition (EMD)-based dictionary generated by collecting a series of intrinsic mode functions (IMFs) while the second one is sparse coding (SC)-based dictionary learned by adaptively iterative optimization. The CMS is based on variation of a sparse features set. Numerical simulations on a simply-supported beam and on a 31-bar planar truss under different damage severities illustrate the effectiveness of the proposed methods for sparse representation and the capabilities of the defined CMS for damage indication. Comparative studies show that the SC-based dictionary outperforms the EMD-based dictionary in sparse representation. Moreover, a series of SDD experimental verifications on a simply-supported beam with a rectangular section in laboratory provide a further support to the proposed methods potentially using in-site acceleration measurements.

关键词： Structural damage detection (SDD) Sparse representation Empirical mode decomposition (EMD) Sparse coding (SC) Damage indicator

来源：评论

学校读者我要写书评

暂无评论

A new structural damage detection strategy of hybrid PSO with Monte Carlo simulations and experimental verifications

引用

MEASUREMENT 2018年 122卷 658-669页

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

Structural damage detection (SDD) is originally an optimization problem by minimizing discrepancy between measured and calculated data of structures. In most cases, natural frequencies and mode shapes are selected to define objective functions for SDD. In this study, a new SDD strategy of hybrid particle swarm optimization (HPSO) is proposed and its availability solution to SDD is studied via Monte Carlo simulations. First of all, PSO algorithms with different parameters are tested via Monte Carlo simulations to decide which combination of parameters is more beneficial for SDD. After that, a powerful local searching Nelder-Mead algorithm is embedded into the PSO with a new strategy, which confirms helpful to enhance the PSO global searching ability numerically and experimentally. Simply-supported beams with 10 and 20 finite elements are simulated respectively which prove our proposed method to be effective in SDD. Further, a series of experiments of a box-section steel beam are designed and fabricated in laboratory. Structural frequencies and mode shapes are measured under different crack damage patterns. The experimental verifications confirm the applicability of the proposed new SDD strategy. The SDD results of the experimental beam also show the outperformance of the proposed new SDD strategy. Some relative discussions are also described in detail.

关键词： Structural health monitoring Structural damage detection (SDD) Hybrid particle swarm optimization (HPSO) Monte Carlo simulations Experimental verifications

来源：评论

学校读者我要写书评

暂无评论

Mathematical modelling of microtubule-tau protein transients: Insights into the superior mechanical behavior of axon

引用

APPLIED MATHEMATICAL MODELLING 2019年 71卷 452-466页

作者： Wu, Jiayu Yuan, Hong Li, Long-yuan Li, Bing Fan, Kunjie Li, Shanqing Lee, Kin-Nam Jinan Univ Inst Appl Mech MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Univ Plymouth Sch Engn Plymouth PL4 8AA Devon England Imperial Coll London Blackett Lab South Kensington Campus London SW7 2AZ England Univ Kent Medway Sch Pharm Chatham ME4 4TB Kent England

Axons with staggered microtubules cross-linked by tau protein possess a remarkable mechanical balance of high specific stiffness and toughness. Owing to their viscoelastic nature, axons exhibit stress rate-dependent mechanical behavior, which is relevant to their selective vulnerability to damage in traumatic brain injury. A Kelvin-Voigt viscoelastic shear lag model is developed to elucidate the mechanical responses of axons under transient tensile force. Analytical closed-form expressions are derived to characterize the relative sliding, stress transfer and failure mechanism between microtubule and tau protein while the axon is stretched transiently. The results from the theoretical solutions elucidate how the MT-tau interface length and stress rate affect the mechanical responses of axon. It is found that axonal failure mechanism may be different under different loading conditions. Long microtubules are more vulnerable to rupture at high stress rate, yet short microtubules are likely to detach from microtubule bundles under large deformations. In the view of multilevel failure of axon, it is illustrated how the vulnerable axons protect themselves from overall damage, and how the axon can simultaneously achieve an outstanding mechanical balance of high specific stiffness and toughness. (C) 2019 Elsevier Inc. All rights reserved.

关键词： Staggered composite Biocomposite Shear lag model Kelvin-Voigt viscoelastic model Traumatic brain injury

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：