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Compressive and cyclic flexural response of double-hooked-end steel fiber reinforced concrete

Demewoz W. MENNA; Aikaterini S. GENIKOMSOU; Mark F. GREEN

《结构与土木工程前沿（英文）》 2022年 第16卷 第9期   页码 1104-1126 doi: 10.1007/s11709-022-0845-x

摘要： Recent developments on high-performance double-hooked-end steel fibers have enhanced the wide applications of steel fiber reinforced concrete (SFRC). This study presents the compressive properties and the cyclic flexural performance of the SFRC that were experimentally examined. Three different double-hooked-end steel fibers at 0.25%, 0.5%, 0.75%, and 1% volume fractions were considered. All fiber types had similar length to diameter ratios, while the first two fiber types had similar anchorage mechanisms (4D) and tensile strength and the third type had different anchorage mechanism (5D) and a higher tensile strength. The increased volumetric ratio of the fibers increased the post-peak compressive strain (ductility), the tensile strength, and the cyclic flexural strength and cumulative energy dissipation characteristics of the SFRC. Among the 4D fibers, the mixtures with the larger steel fibers showed higher flexural strength and more energy dissipation compared to the SFRCs with smaller size fibers. For 1% steel fiber dosage, 4D and 5D specimens showed similar cyclic flexural responses. Finally, a 3D finite element model that can predict the monotonic and cyclic flexural responses of the double-hooked-end SFRC was developed. The calibration process considered the results obtained from the inverse analysis to determine the tensile behavior of the SFRC.

关键词： steel fiber reinforced concrete     fiber geometry     cyclic loading     energy dissipation     finite element modeling     inverse analysis    

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Russian school of the theory and geometry of gearing: Its origin and golden period (1935 --1975)

Dmitry BABICHEV,Sergey LAGUTIN,Natalya BARMINA

《机械工程前沿（英文）》 2016年 第11卷 第1期   页码 44-59 doi: 10.1007/s11465-015-0360-z

摘要：

During the second half of the twentieth century, Soviet scientists were among the world leaders in the theory and geometry of gearing or the theoretical fundamentals of designing gears and gear-cutting tools. The authors of the current paper review works related to the development of the theory of gearing (TG) written in Russian from the mid-1930s to the present. Overall, the review covers more than 400 publications of nearly 200 authors (among more than 1000 studied works). This review involves some works on gear strength and accuracy to attract more experts.

This paper presents a short list of works from the seventeenth century to the nineteenth century and discusses the basic concepts of the TG. This paper also includes a review of more than 160 papers in Russian for the period of 1935–1975, which is the “golden age” of the TG. The main features and achievements during this period are also considered.

The distinctive feature of this review is the use of diagrams that visually present TG experts and the dates and themes of their published works. The diagrams also show the following aspects: 1) The most popular and important themes in a specific period, 2) the most important publications on the themes of interest to readers, and 3) the direction of the works and scope of interests of every researcher.

关键词： theory of gearing (TG)     gear geometry     generating surface     gear synthesis     gear analysis    

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A new proof of Honeycomb Conjecture by fractal geometry methods

Tong ZHANG, Kai DING

《机械工程前沿（英文）》 2013年 第8卷 第4期   页码 367-370 doi: 10.1007/s11465-013-0273-7

摘要：

Based on fractal geometry, we put forward a concise and straightforward method to prove Honeycomb Conjecture—a classical mathematic problem. Hexagon wins the most efficient covering unit in the two- dimensional space, compared with the other two covering units—triangle and square. From this point of view, honeycomb is treated as a hierarchical fractal structure that fully fills the plane. Therefore, the total side length and area are easily calculated and from the results, the covering efficiency of each possible unit is provided quantitatively.

关键词： Honeycomb Conjecture     fractal geometry     hierarchical fractal structure    

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Transmission probability method based on triangle meshes for solving the unstructured geometry neutron

WU Hongchun, LIU Pingping, ZHOU Yongqiang, CAO Liangzhi

《能源前沿（英文）》 2007年 第1卷 第2期   页码 158-166 doi: 10.1007/s11708-007-0020-z

摘要： The fuel assembly or core with unstructured geometry is frequently used in the advanced reactor. To calculate the fuel assembly, the transmission probability method (TPM) is widely used. However, the rectangular or hexagonal meshes are mainly used in the TPM codes for the normal core structure. The triangle meshes are most useful for expressing the complicated unstructured geometry. Even though the finite element method and Monte-Carlo method are well suited for solving the unstructured geometry problem, they are very time-consuming. Therefore, a TPM code based on the triangle meshes is developed here. This code was applied to the hybrid fuel geometry, and compared with the results of the MCNP code and other codes. The results of the comparison were consistent with each other. The TPM with triangle meshes can thus be applied to the two-dimensional arbitrary fuel assembly.

关键词： unstructured geometry     assembly     transmission probability     TPM     rectangular    

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Experimental studies of ash film fractions based on measurement of cenospheres geometry in pulverized

Siqi LIU, Yanqing NIU, Liping WEN, Yang LIANG, Bokang YAN, Denghui WANG, Shi’en HUI

《能源前沿（英文）》 2021年 第15卷 第1期   页码 91-98 doi: 10.1007/s11708-020-0806-9

摘要： In pulverized coal particle combustion, part of the ash forms the ash film and exerts an inhibitory influence on combustion by impeding the diffusion of oxygen to the encapsulated char core, while part of the ash diffuses toward the char core. Despite the considerable ash effects on combustion, the fraction of ash film still remains unclear. However, the research of the properties of cenospheres can be an appropriate choice for the fraction determination, being aware that the formation of cenospheres is based on the model of coal particles with the visco-plastic ash film and a solid core. The fraction of ash film is the ratio of the measuring mass of ash film and the total ash in coal particle. In this paper, the Huangling bituminous coal with different sizes was burnt in a drop-tube furnace at 1273, 1473, and 1673 K with air as oxidizer. A scanning electron microscope (SEM) and cross-section analysis have been used to study the geometry of the collected cenospheres and the effects of combustion parameters on the fraction of ash film. The results show that the ash film fraction increases with increasing temperature and carbon conversion ratio but decreases with larger sizes of coal particles. The high fraction of ash film provides a reasonable explanation for the extinction event at the late burnout stage. The varied values of ash film fractions under different conditions during the dynamic combustion process are necessary for further development of kinetic models.

关键词： ash film fraction     cenospheres     coal combustion     fly ash    

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特大跨度斜拉桥施工几何控制原理的数值验证

黄灿,卜一之,张清华

《中国工程科学》 2009年 第11卷 第1期   页码 87-91

摘要：

以苏通长江大桥为研究对象，通过数值仿真分析验证了几何控制原理的正确性。通过对施工过程中临时荷载和环境温度对于结构线形影响的系统分析和研究结果表明，在考虑施工全过程几何非线性影响的条件下，临时荷载及环境温度等因素仅影响施工过程中的结构状态，基本不影响成桥的结构线形和内力状态，几何控制原理适用于超大斜拉桥施工控制，采用几何控制原理能够获得良好的施工控制结果。

关键词： 斜拉桥     几何控制     几何非线性     数值验证    

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Experimental study of the effects of structured surface geometry on water spray cooling performance in

Minghou LIU, Yaqing WANG, Dong LIU, Kan XU, Yiliang CHEN

《能源前沿（英文）》 2011年 第5卷 第1期   页码 75-82 doi: 10.1007/s11708-010-0014-0

摘要： Experiments were conducted to study the effects of enhanced surfaces on heat transfer performance during water spray cooling in non-boiling regime. The surface enhancement is straight fin. The structures were machined on the top surface of heated copper blocks with a cross-sectional area of 10 mm×10 mm. The spray was performed using Unijet full cone nozzles with a volumetric flux of 0.044–0.053 m /(m ·s) and a nozzle height of 17 mm. It is found that the heat transfer is obviously enhanced for straight fin surfaces relative to the flat surface. However, the increment decreases as the fin height increases. For flat surface and enhanced surfaces with a fin height of 0.1 mm and 0.2 mm, as the coolant flux increases, the heat flux increases as well. However, for finned surface with a height of 0.4 mm, the heat flux is not sensitive to the coolant volumetric flux. Changed film thickness and the form of water/surface interaction due to an enhanced surface structure (different fin height) are the main reasons for changing of the local heat transfer coefficient.

关键词： spray cooling     finned surface     heat transfer    

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基于几何控制法的短线预制拼装箱梁研究

王敏,张永涛,刘景红,刘毅,黄跃

《中国工程科学》 2009年 第11卷 第11期   页码 79-81

摘要：

针对短线预制拼装箱梁几何控制过程中制造及安装阶段的误差控制问题，在分析了误差产生原因的基础上，结合苏通大桥B2标的现场实际情况，介绍以几何控制理论为基础，参数敏感性分析为方法，辅以现代误差分析技术和软件开发技术，实现短线法预制拼装的全过程施工数值化管理与控制。

关键词： 几何控制     误差分析     最小二乘法     短线预制拼装    

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Edge preparation methods for cutting tools: a review

《机械工程前沿（英文）》 2023年 第18卷 第4期 doi: 10.1007/s11465-023-0766-y

摘要： Edge preparation can remove cutting edge defects, such as burrs, chippings, and grinding marks, generated in the grinding process and improve the cutting performance and service life of tools. Various edge preparation methods have been proposed for different tool matrix materials, geometries, and application requirements. This study presents a scientific and systematic review of the development of tool edge preparation technology and provides ideas for its future development. First, typical edge characterization methods, which associate the microgeometric characteristics of the cutting edge with cutting performance, are briefly introduced. Then, edge preparation methods for cutting tools, in which materials at the cutting edge area are removed to decrease defects and obtain a suitable microgeometry of the cutting edge for machining, are discussed. New edge preparation methods are explored on the basis of existing processing technologies, and the principles, advantages, and limitations of these methods are systematically summarized and analyzed. Edge preparation methods are classified into two categories: mechanical processing methods and nontraditional processing methods. These methods are compared from the aspects of edge consistency, surface quality, efficiency, processing difficulty, machining cost, and general availability. In this manner, a more intuitive understanding of the characteristics can be gained. Finally, the future development direction of tool edge preparation technology is prospected.

关键词： edge preparation method     preparation principle     cutting edge geometry     edge characterization     tool performance    

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Performance of fiber reinforced clayey sand composite

Amin CHEGENIZADEH, Hamid NIKRAZ

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 147-152 doi: 10.1007/s11709-012-0158-6

摘要： Soils and their related behavior have always been the subject of many studies. Recent researches show some interests in investigation of inclusion of randomly distributed fiber in soil. This study focuses on effect of fiber inclusion on the strength and other parameters of clayey sand composite material. First part of this study is related to effective parameters on strength of the clayey sand composite with using natural fiber and plastic fiber and different fiber contents and length. Triaxial consolidated undrained (CU) tests were carried out to investigate behavior of the composite under different condition. The fiber percentage varied from 0% (for unreinforced samples) to 4% and fiber length varied from 8 to 25 mm. The fiber length and fiber content found to play important rule on the strength of fiber reinforced composite.

关键词： triaxial     consolidated undrained (CU)     fiber     strength    

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Mechanical properties of steel, glass, and hybrid fiber reinforced reactive powder concrete

Atheer H.M. ALGBURI, M. Neaz SHEIKH, Muhammad N.S. HADI

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 998-1006 doi: 10.1007/s11709-019-0533-7

摘要： This study examines the properties of fiber-reinforced reactive powder concrete (FR-RPC). Steel fibers, glass fibers, and steel-glass hybrid fibers were used to prepare the FR-RPC. The non-fibrous reactive powder concrete (NF-RPC) was prepared as a reference mix. The proportion of fibers by volume for all FR-RPC mixes was 1.5%. Steel fibers of 13 mm length and 0.2 mm diameter were used to prepare the steel fiber-reinforced RPC (SFR-RPC). Glass fibers of 13 mm length and 1.3 mm diameter were used to prepare the glass fiber-reinforced RPC (GFR-RPC). The hybrid fiber-reinforced RPC (HFR-RPC) was prepared by mixing 0.9% steel fibers and 0.6% glass fibers. Compressive strength, axial load-axial deformation behavior, modulus of elasticity, indirect tensile strength, and shear strength of the RPC mixes were investigated. The results showed that SFR-RPC achieved higher compressive strength, indirect tensile strength and shear strength than NF-RPC, GFR-RPC, and HFR-RPC. Although the compressive strengths of GFR-RPC and HFR-RPC were slightly lower than the compressive strength of NF-RPC, the shear strengths of GFR-RPC and HFR-RPC were higher than that of NF-RPC.

关键词： reactive powder concrete     steel fiber     glass fiber     hybrid fiber    

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国外光纤光纤带和带状光缆技术的最新发展

刘良炎

《中国工程科学》 2001年 第3卷 第9期   页码 86-94

摘要：

综合介绍了近年国外关于低衰耗的色散补偿光纤，非零色散位移光纤，用于恶劣环境的碳涂覆和氮化硅涂覆光纤的研究；光纤带制造技术包括光纤带的结构、涂层、性能、生产工艺，大芯数光纤带状光缆包括层绞式松管、中心松管式、骨架式、干缆芯带状光缆的设计制造技术的最新进展。

关键词： 光纤通信     低衰耗光纤     光纤带     光纤带状光缆    

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高性能零件的性能与几何参数一体化精密加工方法与技术

郭东明

《中国工程科学》 2011年 第13卷 第10期   页码 47-57

摘要：

随着高端装备和产品的不断发展，对装备和产品制造的性能要求也越来越多和越来越高，涌现出一大批高性能指标要求的关键零部件，其加工已由以往的单纯几何形状和尺寸精度要求，跃升为以性能要求为主、性能与几何参数一体化的精密加工要求。这些高性能零件多呈精密复杂曲面、超高精度，以及材料超硬、超脆、超黏等难加工特征，其性能受几何、材料等多因素耦合作用，采用传统工艺进行精密加工制造十分困难，存在废品率高、加工效率低，特别是性能指标难以保证等难题。从高端制造装备业的需求出发，提出并阐明了高性能零件的特点、分类以及数字化可控去除加工方式的内涵，在此基础上指出了四类高性能零件精密加工所涉及的关键问题，并着重介绍了这些问题的研究现状、存在的难点和可行的解决方案，为面向高性能要求的性能与几何参数一体化的加工理论、方法和工艺技术体系的建立提供参考，以解决高性能零件的精密制造难题。

关键词： 高性能     性能与几何参数一体化     精密加工     难加工材料     复杂曲面    

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Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

《化学科学与工程前沿（英文）》 2021年 第15卷 第2期   页码 384-398 doi: 10.1007/s11705-020-1928-7

摘要： The jet-flow high shear mixer (JF-HSM) is a new type of intensified equipment with special configurations of the rotor and the stator. The mass transfer property and power consumption were studied in the solid-liquid system for a series of JF-HSMs involving different configuration parameters, such as rotor diameter, rotor blade inclination, rotor blade bending direction, stator diameter, and stator bottom opening diameter. The flow characteristics were examined by computational fluid dynamic simulations. Results indicate that the turbulent power consumption of the JF-HSM is affected by the change in rotor blade inclination and stator bottom opening. With the increase in the shear head size and the change in the rotor into a backward-curved blade, the solid-liquid mass transfer rate can be remarkably increased under the same input power. Dimensionless correlations for the mass transfer coefficient and power consumption were obtained to guide the scale-up design and selection of such a new type of equipment to intensify the overall mixing efficiency.

关键词： jet-flow high shear mixer     solid particle dissolution     power consumption characteristics     CFD Simulation    

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Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 411-428 doi: 10.1007/s11709-023-0928-3

摘要： In this study, ultrahigh-performance fiber-reinforced concrete (UHPFRC) used in a type B70 concrete sleeper is investigated experimentally and parametrically. The main parameters investigated are the steel fiber volume fractions (0%, 0.5%, 1%, and 1.5%). Under European standards, 35 UHPFRC sleepers are subjected to static bending tests at the center and rail seat sections, and the screw on the fastening system is pulled out. The first cracking load, failure load, failure mode, crack propagation, load–deflection curve, load–crack width, and failure load from these tests are measured and compared with those of a control sleeper manufactured using normal concrete C50. The accuracy of the parametric study is verified experimentally. Subsequently, the results of the study are applied to UHPFRC sleepers with different concrete volumes to investigate the effects of the properties of UHPFRC on their performance. Experimental and parametric study results show that the behavior of UHPFRC sleepers improves significantly when the amount of steel fiber in the mix is increased. Sleepers manufactured using UHPFRC with a steel fiber volume fraction of 1% and a concrete volume less than 25% that of standard sleeper B70 can be used under the same loads and requirements, which contributes positively to the cost and surrounding environment.

关键词： pre-stressed concrete sleeper     ultrahigh performance fiber-reinforced concrete     pull-out test     static bending test     steel fiber     aspect ratio     volume fraction    

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标题 作者 时间 类型 操作

Compressive and cyclic flexural response of double-hooked-end steel fiber reinforced concrete

Demewoz W. MENNA; Aikaterini S. GENIKOMSOU; Mark F. GREEN

期刊论文

Russian school of the theory and geometry of gearing: Its origin and golden period (1935 --1975)

Dmitry BABICHEV,Sergey LAGUTIN,Natalya BARMINA

期刊论文

A new proof of Honeycomb Conjecture by fractal geometry methods

Tong ZHANG, Kai DING

期刊论文

Transmission probability method based on triangle meshes for solving the unstructured geometry neutron

WU Hongchun, LIU Pingping, ZHOU Yongqiang, CAO Liangzhi

期刊论文

Experimental studies of ash film fractions based on measurement of cenospheres geometry in pulverized

Siqi LIU, Yanqing NIU, Liping WEN, Yang LIANG, Bokang YAN, Denghui WANG, Shi’en HUI

期刊论文

特大跨度斜拉桥施工几何控制原理的数值验证

黄灿,卜一之,张清华

期刊论文

Experimental study of the effects of structured surface geometry on water spray cooling performance in

Minghou LIU, Yaqing WANG, Dong LIU, Kan XU, Yiliang CHEN

期刊论文

基于几何控制法的短线预制拼装箱梁研究

王敏,张永涛,刘景红,刘毅,黄跃

期刊论文

Edge preparation methods for cutting tools: a review

期刊论文

Performance of fiber reinforced clayey sand composite

Amin CHEGENIZADEH, Hamid NIKRAZ

期刊论文

Mechanical properties of steel, glass, and hybrid fiber reinforced reactive powder concrete

Atheer H.M. ALGBURI, M. Neaz SHEIKH, Muhammad N.S. HADI

期刊论文

国外光纤光纤带和带状光缆技术的最新发展

刘良炎

期刊论文

高性能零件的性能与几何参数一体化精密加工方法与技术

郭东明

期刊论文

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

期刊论文

Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

期刊论文