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Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 261-269 doi: 10.1007/s11465-010-0100-3

摘要: Microgears are increasingly important in industry. Compared to normal gears, the quality assurance of microgears needs more accurately measured data and simple but feasible measurement methods because of their dimension particula

关键词: microgear     optical distance measurement     profile deviation     CWL sensor     micromechanical technology (MMT)    

An adaptive data-driven method for accurate prediction of remaining useful life of rolling bearings

Yanfeng PENG, Junsheng CHENG, Yanfei LIU, Xuejun LI, Zhihua PENG

《机械工程前沿(英文)》 2018年 第13卷 第2期   页码 301-310 doi: 10.1007/s11465-017-0449-7

摘要:

A novel data-driven method based on Gaussian mixture model (GMM) and distance evaluation technique (DET) is proposed to predict the remaining useful life (RUL) of rolling bearings. The data sets are clustered by GMM to divide all data sets into several health states adaptively and reasonably. The number of clusters is determined by the minimum description length principle. Thus, either the health state of the data sets or the number of the states is obtained automatically. Meanwhile, the abnormal data sets can be recognized during the clustering process and removed from the training data sets. After obtaining the health states, appropriate features are selected by DET for increasing the classification and prediction accuracy. In the prediction process, each vibration signal is decomposed into several components by empirical mode decomposition. Some common statistical parameters of the components are calculated first and then the features are clustered using GMM to divide the data sets into several health states and remove the abnormal data sets. Thereafter, appropriate statistical parameters of the generated components are selected using DET. Finally, least squares support vector machine is utilized to predict the RUL of rolling bearings. Experimental results indicate that the proposed method reliably predicts the RUL of rolling bearings.

关键词: Gaussian mixture model     distance evaluation technique     health state     remaining useful life     rolling bearing    

盾构隧道长距离独头掘进的控制测量技术

许维青,韩福忠

《中国工程科学》 2010年 第12卷 第12期   页码 56-58

摘要:

北京地下直径线盾构独头掘进距离达5.2 km,因此隧道贯通精度控制难度大。通过测量精度分析,单纯通过导线测量已不能满足设计规定的贯通限差要求,施工中通过导线直接传递定向、洞内加测陀螺边、地上地下控制网紧密联系等辅助方法,提高了贯通横向误差的精度,达到了预期效果。

关键词: 盾构     长距离     独头掘进     控制测量    

Seismic safety evaluation methodology for masonry building and retrofitting using splint and bandagetechnique with wire mesh

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

《结构与土木工程前沿(英文)》 2022年 第16卷 第4期   页码 478-505 doi: 10.1007/s11709-022-0817-1

摘要: The paper presents a seismic safety assessment of unreinforced masonry (URM) building using two approaches. The first approach uses the ‘Pier Analysis’ method, based on the concept of equivalent lateral stiffness, where in-plane and out-of-plane actions are considered independently. The second approach is developed with the program SAP2000, where the linear response is evaluated using continuum ‘finite element modelling’ (FEM). Both methods are compared to evaluate the safety of wall piers and the differences in the outcomes under combined gravitational and lateral seismic forces. The analysis results showed that few wall elements are unsafe in in-plane and out-of-plane tension. It is also observed that the pier analysis method is conservative compared to FEM, but can be used as a simplified and quick tool in design offices for safety assessment, with reasonable accuracy. To safeguard the URM wall piers under lateral loads, a retrofitting technique is adopted by providing vertical and horizontal belts called splints and bandages, respectively, using welded wire mesh (WWM) reinforcement. The study using the ‘Pier Analysis’ shows that the lateral load capacity of unsafe URM piers can be enhanced up to 3.67 times and made safe using the applied retrofitting technique. Further, the retrofitting design methodology and recommendations for application procedures to on-site URM buildings are discussed in detail.

关键词: unreinforced masonry     seismic in-plane and out-of-plane forces     pier analysis     finite element modelling     splint and bandage technique with wire mesh    

Establishment of the Comprehensive Evaluation System of Cold Stamping Die Quality

LU Xiao-chun, GUO Sheng, RUAN Feng

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 80-84 doi: 10.1007/s11465-005-0021-8

摘要:

A comprehensive evaluation system of die quality, a multiplayer hierarchical amendment index system according to the characteristics of cold stamping die production, an evaluation standard referring to the technique and design rules of dies, and a scientific evaluation by using the multiplayer hierarchical and the fuzzy comprehensive evaluation methods are presented in this paper. The applications show that the system can be used to evaluate the die quality objectively, fairly, and reasonably.

关键词: scientific evaluation     stamping     multiplayer hierarchical     technique     evaluation standard    

Improved directional-distance filter

JIN Lianghai, LI Dehua

《机械工程前沿(英文)》 2008年 第3卷 第2期   页码 205-211 doi: 10.1007/s11465-008-0025-2

摘要: This paper proposes a new spatial-distance weighting function. By combining the weighting function and the traditional directional-distance filter (DDF) in a novel way, a new vector filter - the adaptive distance-weighted directional-distance filter (ADWDDF) - is presented. The experimental results show that the proposed solution provides better filtering performance and preserves better image chromaticity and edge or detail information compared with the traditional DDF and some other typical vector filters.

关键词: information     distance-weighted directional-distance     ADWDDF     traditional DDF     spatial-distance weighting    

Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete

《结构与土木工程前沿(英文)》   页码 1341-1356 doi: 10.1007/s11709-023-0988-4

摘要: This study empirically investigated the influence of freeze–thaw cycling on the dynamic splitting tensile properties of steel fiber reinforced concrete (SFRC). Brazilian disc splitting tests were conducted using four loading rates (0.002, 0.02, 0.2, and 2 mm/s) on specimens with four steel fiber contents (0%, 0.6%, 1.2%, and 1.8%) subjected to 0 and 50 freeze–thaw cycles. The dynamic splitting tensile damage characteristics were evaluated using acoustic emission (AE) parameter analysis and Fourier transform spectral analysis. The results quantified using the freeze–thaw damage factor defined in this paper indicate that the degree of damage to SFRC caused by freeze–thaw cycling was aggravated with increasing loading rate but mitigated by increasing fiber content. The percentage of low-frequency AE signals produced by the SFRC specimens during loading decreased with increasing loading rate, whereas that of high-frequency AE signals increased. Freeze–thaw action had little effect on the crack types observed during the early and middle stages of the loading process; however, the primary crack type observed during the later stage of loading changed from shear to tensile after the SFRC specimens were subjected to freeze–thaw cycling. Notably, the results of this study indicate that the freeze–thaw damage to SFRC reduces AE signal activity at low frequencies.

关键词: steel fiber reinforced concrete     freeze–thaw cycling     Brazilian disc splitting test     acoustic emission technique     dynamic splitting tensile acoustic emission properties    

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 249-253 doi: 10.1007/s11465-011-0124-3

摘要:

This paper introduces the basic conception of information fusion and some fusion diagnosis methods commonly used nowadays in rotating machinery. From the thought of the information fusion, a new quantitative feature index monitoring and diagnosing the vibration fault of rotating machinery, which is called distance of information entropy, is put forward on the basis of the singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet energy spectrum entropy, and wavelet space feature entropy in time-frequency domain. The mathematic deduction suggests that the conception of distance of information entropy is accordant with the maximum subordination principle in the fuzzy theory. Through calculation it has been proved that this method can effectively distinguish different fault types. Then, the accuracy of rotor fault diagnosis can be improved through the curve chart of the distance of information entropy at multi-speed.

关键词: rotating machinery     information fusion     fault diagnosis     Information entropy     distance of the information entropy    

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 796-811 doi: 10.1007/s11709-023-0922-9

摘要: Conventional geotechnical software limits the use of the strength reduction method (SRM) based on the Mohr–Coulomb failure criterion to analyze the slope safety factor (SF). The use of this constitutive model is impractical for predicting the behavior of all soil types. In the present study, an innovative numerical technique based on SRM was developed to determine SF using the finite element method and considering the extended Cam–clay constitutive model for clayey gravel soil as opposed to the Mohr–Coulomb model. In this regard, a novel user subroutine code was employed in ABAQUS to reduce the stabilizing forces to determine the failure surfaces and resist and drive shear stresses on a slope. After validating the proposed technique, it was employed to investigate the performance of terraced slopes in the context of a case study. The impacts of geometric parameters and different water table elevations on the SF were examined. The results indicated that an increase in the upper and lower slope heights led to a decrease in SF, and a slight increase in the horizontal offset led to an increase in the SF. Moreover, when the water table elevation was lower than the toe of the terraced slope, the SF increased because of the increase in the uplift force as a resistant component.

关键词: terraced slope     safety factor     finite element method     ABAQUS     extended Cam–clay    

Efficient utilization of wind power: Long-distance transmission or local consumption?

Yuanzhang SUN, Xiyuan MA, Jian XU, Yi BAO, Siyang LIAO

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 440-455 doi: 10.1007/s11465-017-0440-3

摘要:

Excess wind power produced in wind-intensive areas is normally delivered to remote load centers via long-distance transmission lines. This paper presents a comparison between long-distance transmission, which has gained popularity, and local energy consumption, in which a fraction of the generated wind power can be locally consumed by energy-intensive industries. First, the challenges and solutions to the long-distance transmission and local consumption of wind power are presented. Then, the two approaches to the utilization of wind power are compared in terms of system security, reliability, cost, and capability to utilize wind energy. Finally, the economic feasibility and technical feasibility of the local consumption of wind power are demonstrated by a large and isolated industrial power system, or supermicrogrid, in China. The coal-fired generators together with the short-term interruptible electrolytic aluminum load in the supermicrogrid are able to compensate for the intermittency of wind power. In the long term, the transfer of high-energy-consumption industries to wind-rich areas and their local consumption of the available wind power are beneficial.

关键词: wind power     long-distance transmission     local consumption     supermicrogrid    

Cracking resistance performance of super vertical-distance pumped SFRC

JIANG Jinyang, SUN Wei, ZHANG Yunsheng, CHEN Cuicui, WANG Jing

《结构与土木工程前沿(英文)》 2008年 第2卷 第2期   页码 179-183 doi: 10.1007/s11709-008-0018-6

摘要: The mix ratio of steel fiber reinforced concrete (SFRC) was optimized using the principles that workability must meet the pumping demand and anti-cracking performance should be optimal. The effect of SFRC on the initial cracking load, the ultimate load and the crack width of the reinforced concrete (RC) member were analyzed in this paper. It was found that the admixture had good preservation of moisture and adhesion and the fibers distributed homogeneously in one hour out of the machine. According to the pumping results, the SFRC could be pumped vertically up to 306 m. Based on the standard computation formula of cracks, the maximum crack width of an RC member with 0.8% steel fiber (by volume) is about 32% lower than that of standard RC member. Through an experimental research on full-scale model tests for the steel and concrete composite anchorage zone on a pylon, the SFRC not only remarkably increases the crack resistance and the ultimate load, but the initial load also improves 33% approximately. It is also indicated that plastic shrinkage cracking of SFRC in which volume fraction of steel fibers is 0.8% can be restrained obviously and the unrestrained drying shrinkage can be diminished by about 50% at early age. The results confirmed that the SFRC can lessen the shrinkage crack of concrete and enhance markedly the direct tensile strength. Therefore, the SFRC can solve the key question of crack resistance for the anchorage zone of a bridge tower.

Variable eccentric distance-based tool path generation for orthogonal turn-milling

Fangyu PENG,Wei WANG,Rong YAN,Xianyin DUAN,Bin LI

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 352-366 doi: 10.1007/s11465-015-0361-y

摘要:

This study proposes an algorithm for maximizing strip width in orthogonal turn-milling based on variable eccentric distance. The machining error model is first established based on the local cutting profile at the contact line. The influencing factors of the strip width are then investigated to analyze their features and determine an optimizing strategy. The optimized model for maximum machining strip width is formulated by adopting a variable eccentric distance. Hausdorff distance and Fréchet distance are introduced in this study to implement the constraint function of the machining error in the optimized model. The computing procedure is subsequently provided. Simulations and experiments have been conducted to verify the effectiveness of the proposed algorithm.

关键词: orthogonal turn-milling     variable eccentric distance     local cutting profile     machining strip-width maximization    

论减灾系统的远程公平化

姚清林

《中国工程科学》 2009年 第11卷 第6期   页码 153-158

摘要:

远程公平化是偏向于远程的公平,旨在寻求系统整体的优化。在一定的约束条件下,通过域的分隔、变形,中心的定位与相应的远程运作机制,可消减不利因素对系统的干扰,扩大结构瓶颈,调优技术性弱点、难点、远点、易忽视点的指标期望与实现值,抑小扬大,隐近就远,弥补系统缺陷,或于不完备的条件下构建 完备系统,保障全局利益与远效,推进减灾管理的科学化,改善各个方面的减灾工作。

关键词: 远程公平化     减灾     管理     地震    

论汽车轻量化

马鸣图,易红亮,路洪洲,万鑫铭

《中国工程科学》 2009年 第11卷 第9期   页码 20-27

摘要:

论述了汽车轻量化的意义、表征参量、评价方法、实施路径和方法;轻量化的设计,零部件和构件的功能与材料性能参量的关系以及先进成形技术的应用。结合近期轻量化的相关进展和笔者的工作,对汽车轻量化进行了全面系统的论述,以期给出关于汽车轻量化较完整的概念和认识。

关键词: 汽车轻量化     评价方法     表征参量     零件功能     材料性能     成形技术    

General modeling and optimization technique for real-world earth observation satellite scheduling

《工程管理前沿(英文)》   页码 695-709 doi: 10.1007/s42524-023-0263-3

摘要: Over the last two decades, many modeling and optimization techniques have been developed for earth observation satellite (EOS) scheduling problems, but few of them show good generality to be engineered in real-world applications. This study proposes a general modeling and optimization technique for common and real-world EOS scheduling cases; it includes a decoupled framework, a general modeling method, and an easy-to-use algorithm library. In this technique, a framework that decouples the modeling, constraints, and optimization of EOS scheduling problems is built. With this framework, the EOS scheduling problems are appropriately modeled in a general manner, where the executable opportunity, another format of the well-known visible time window per EOS operation, is viewed as a selectable resource to be optimized. On this basis, 10 types of optimization algorithms, such as Tabu search and genetic algorithm, and a parallel competitive memetic algorithm, are developed. For simplified EOS scheduling problems, the proposed technique shows better performance in applicability and effectiveness than the state-of-the-art algorithms. In addition, a complicatedly constrained real-world benchmark exampled by a four-EOS Chinese commercial constellation is provided, and the technique is qualified and outperforms the in-use scheduling system by more than 50%.

关键词: earth observation satellite     scheduling     general technique     optimization algorithm     commercial constellation     real-world     benchmark    

标题 作者 时间 类型 操作

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

期刊论文

An adaptive data-driven method for accurate prediction of remaining useful life of rolling bearings

Yanfeng PENG, Junsheng CHENG, Yanfei LIU, Xuejun LI, Zhihua PENG

期刊论文

盾构隧道长距离独头掘进的控制测量技术

许维青,韩福忠

期刊论文

Seismic safety evaluation methodology for masonry building and retrofitting using splint and bandagetechnique with wire mesh

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

期刊论文

Establishment of the Comprehensive Evaluation System of Cold Stamping Die Quality

LU Xiao-chun, GUO Sheng, RUAN Feng

期刊论文

Improved directional-distance filter

JIN Lianghai, LI Dehua

期刊论文

Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete

期刊论文

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

期刊论文

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

期刊论文

Efficient utilization of wind power: Long-distance transmission or local consumption?

Yuanzhang SUN, Xiyuan MA, Jian XU, Yi BAO, Siyang LIAO

期刊论文

Cracking resistance performance of super vertical-distance pumped SFRC

JIANG Jinyang, SUN Wei, ZHANG Yunsheng, CHEN Cuicui, WANG Jing

期刊论文

Variable eccentric distance-based tool path generation for orthogonal turn-milling

Fangyu PENG,Wei WANG,Rong YAN,Xianyin DUAN,Bin LI

期刊论文

论减灾系统的远程公平化

姚清林

期刊论文

论汽车轻量化

马鸣图,易红亮,路洪洲,万鑫铭

期刊论文

General modeling and optimization technique for real-world earth observation satellite scheduling

期刊论文