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原位统计分布分析 3

磁浮技术 2

统计偏析度 2

统计符合度 2

鲁棒控制 2

μ综合 1

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交流永磁同步电机;滑模控制器;扩张状态观测器;鲁棒控制;运动控制 1

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A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn end mills

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0757-z

摘要: Flanks of end mills are prone to wear in a long machining process. Regrinding is widely used in workshops to restore the flank to an original-like state. However, the traditional method involves material waste by trial and error and dramatically decreases the potential regrinding. Moreover, over-cut would happen to the flutes of worn cutters in the regrinding processes because of improper wheel path. This study presented a new approach to planning the wheel path for regrinding worn end mills to minimize material loss and recover the over-cut. In planning, a scaling method was developed to determine the maximum size of the new cutter according to the similarity of cutter shapes before and after regrinding. Then, the wheel path is first generated by envelope theory to regrind the worn area with a four-axis computer numerical control grinder according to the new size of cutters. Moreover, a second regrinding strategy is applied to recover the flute shape over-cut in the first grinding. Finally, the proposed method is verified by an experiment. Results showed that the proposed approach could save 25% of cutter material compared with the traditional method and ensure at least three regrinding times. This work effectively provides a general regrinding solution for the worn flank with maximum material-saving and regrinding period.

关键词: flank-regrinding     worn end mill     wheel position and orientation     material loss     over-cut    

Numerical investigation of the influence of casting techniques on fiber orientation distribution in ECC

Chung Nguyen VAN; Hai TRAN THANH; Thuc Nhu NGUYEN; Jianchun LI

《结构与土木工程前沿(英文)》 2022年 第16卷 第11期   页码 1424-1435 doi: 10.1007/s11709-022-0870-9

摘要: Engineered cementitious composites (ECC), also known as bendable concrete, were developed based on engineering the interactions between fibers and cementitious matrix. The orientation of fibers, in this regard, is one of the major factors influencing the ductile behavior of this material. In this study, fiber orientation distributions in ECC beams influenced by different casting techniques are evaluated via numerical modeling of the casting process. Two casting directions and two casting positions of the funnel outlet with beam specimens are modeled using a particle-based smoothed particle hydrodynamics (SPH) method. In this SPH approach, fresh mortar and fiber are discretized by separated mortar and fiber particles, which smoothly interact in the computational domain of SPH. The movement of fiber particles is monitored during the casting simulation. Then, the fiber orientations at different sections of specimens are determined after the fresh ECC stops flowing in the formwork. The simulation results show a significant impact of the casting direction on fiber orientation distributions along the longitudinal wall of beams, which eventually influence the flexural strength of beams. In addition, casting positions show negligible influences on the orientation distribution of fibers in the short ECC beam, except under the pouring position.

关键词: ECC     fiber orientation distribution     casting direction     casting position    

高温合金压气机盘锻件纵断面中铌分布的原位统计分布分析表征

王海舟,李美玲,庄景云

《中国工程科学》 2011年 第13卷 第10期   页码 19-27

摘要:

采用原位统计分布分析表征技术系统研究了GH169高温合金压气机盘纵断面不同部位铌分布的规律。以所得到的与样品原位置相对应的数以万计原始信号系统解析为基础,进而获得压气机盘锻件的纵断面不同部位铌的定量统计分布信息以及加工工艺过程中铌的迁移规律。准确计算判定了盘纵断面不同部位铌的最大偏析度,提出了95 %置信度时中位值置信扩展率,即统计偏析度(S)新参数,用以表征铌在压气机盘中分布的均匀度;提出了所有数据在特定含量区间(C0±R)的频度(权重)比率,即统计符合度(F)新参数,用以表征预设质量控制区间铌含量的一致性的概率。采用原位统计分布分析的表征方法,准确定量地评定了高温合金压气机盘件纵断面不同部位铌的分布均匀度和符合度,为加工后盘件的质量控制评估提供了参考。

关键词: 原位统计分布分析表征技术     高温合金压气机盘         统计偏析度     统计符合度     质量控制    

An automated arc spray tooling system for rapid die-making of large-sized automobile body panels

HE Zhong-yun, LU Bing-heng, WANG Yi-qing, HONG Jun, TANG Yi-ping

《机械工程前沿(英文)》 2006年 第1卷 第2期   页码 209-214 doi: 10.1007/s11465-006-0012-4

摘要: A creative robot wrist consisting of link mechanisms and a novel robot motion control method based on the cross-sectional vector contours of an STL-formatted model was proposed. By using the wrist and the control method, an industrial robot with five degrees of freedom for rapid tooling using metal arc spraying and electric brush plating techniques was developed. The wrist of the robot including a specially designed link mechanism can maintain the position of the spraying point on the surface of the master pattern whatever the orientation of the gun. Therefore, the kinematic nonlinear coupling between the position mechanism and orientation mechanism in a traditional robot can be avoided. The only input of the control system is the STL-formatted 3D CAD model of the pattern. Without the need of any manual programming, the metal arc spraying and brush plating (if necessary) processes can be performed automatically and efficiently after receiving the 3D CAD data of the pattern. Using this robot system in new car development and trial production, the cost and lead-time can be reduced substantially as compared with the conventional tool making method.

关键词: industrial     position mechanism     orientation     surface     cross-sectional    

WEIS wheel speed real-time measuring method for VOSM

Mengyao PAN, Guixiong LIU, Xiaobin HONG, Tusheng LIN,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 322-327 doi: 10.1007/s11465-010-0022-0

摘要: Wheel speed is one of the key parameters of vehicle operating attitude. To solve the problems in traditional wheel speed measuring methods, such as low measurement precision and the lack of real-time monitoring of the vehicle’s operating attitude, a wheel embedded intelligent sensors (WEIS) wheel speed measuring method for vehicle operating safety states monitoring (VOSM) is innovatively proposed. Radial acceleration signal is obtained through a WEIS module embedded in the hub. Using wavelet packet to implement wavelet de-noising for the non-stationary acceleration signals, and adopting short-time Fourier transform (STFT) algorithm to extract the signal characteristics, the wheel speed measurement can be achieved. The experimental result shows that under experimental conditions the speed measurement error is −2.05%, and the speed measuring response time is 0.45 s.

关键词: wheel embedded     intelligent sensing     wheel speed     monitoring    

Experimental and CFD analysis of nozzle position of subsonic ejector

Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN

《能源前沿(英文)》 2009年 第3卷 第2期   页码 167-174 doi: 10.1007/s11708-009-0001-5

摘要: The influence of nozzle position on the performance of an ejector was analyzed qualitatively with free jet flow model. Experimental investigations and computational fluid dynamics (CFD) analysis of the nozzle position of the subsonic ejector were also conducted. The results show that there is an optimum nozzle position for the ejector. The ejecting coefficient reaches its maximum when the nozzle is positioned at the optimum and decreases when deviating. Moreover, the nozzle position of an ejector is not a fixed value, but is influenced greatly by the flow parameters. Considering the complexity of the ejector, CFD is reckoned as a useful tool in the design of ejectors.

关键词: ejector     nozzle position     ejecting coefficient     CFD    

Simulation and analysis of grinding wheel based on Gaussian mixture model

Yulun CHI, Haolin LI

《机械工程前沿(英文)》 2012年 第7卷 第4期   页码 427-432 doi: 10.1007/s11465-012-0350-3

摘要:

This article presents an application of numerical simulation technique for the generation and analysis of the grinding wheel surface topographies. The ZETA 20 imaging and metrology microscope is employed to measure the surface topographies. The Gaussian mixture model (GMM) is used to transform the measured non-Gaussian field to Gaussian fields, and the simulated topographies are generated. Some numerical examples are used to illustrate the viability of the method. It shows that the simulated grinding wheel topographies are similar with the measured and can be effective used to study the abrasive grains and grinding mechanism.

关键词: grinding wheel     3D topographies measurement     Gaussian mixture model     simulation    

Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0701-7

摘要: The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles, but its riveting connection remains a problem. To address this problem, this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method, analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy (Mg/Al) assembled wheel, and constructed some major evaluation indicators. The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints. The punching riveting process parameters of the assembled wheel joints were defined as design variables, and the fatigue and impact performance of the assembled wheel was defined as the optimization objective. The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment, grey relational analysis, analytic hierarchy process, principal component analysis, and entropy weighting methods. The optimization results of the three weighting methods were compared, and the optimal combination of design variables was determined. The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.

关键词: magnesium/aluminum assembled wheel     riveting residual stress     fatigue analysis     impact analysis     multi-objective optimization    

Lightening structure optimization on turbine wheel of vehicular turbocharger

ZHAO Junsheng, MA Chaochen, HU Liaoping

《能源前沿(英文)》 2008年 第2卷 第4期   页码 422-426 doi: 10.1007/s11708-008-0098-y

摘要: Based on basic principle of optimization design, structure optimization of turbine is conducted using optimization module of ANSYS and APDL in order to get the minimum turbine weight. Meanwhile, the original blade profile and flow passage are maintained, and the structural strength of the turbine are guaranteed. Considering assembly technique and cast requirement, the structure of the modified turbine is determined which can save 6.91 percent of the material compared with the original one. The modified turbine not only saved material, but also gained better effect of mass distribution between the turbine and the compressor impeller. The result can provide useful reference to engineering application of turbocharger.

关键词: requirement     technique     engineering application     turbocharger     reference    

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0732-0

摘要: To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance.

关键词: asteroid sampling     wheel brush sampler     discrete element method     parameter calibration     experimental research    

泰州大桥钢桥面铺装轮载谱研究

李洪涛,潘友强,张志祥

《中国工程科学》 2012年 第14卷 第5期   页码 85-89

摘要:

调研了江苏省内三座跨江大桥2007—2010年的交通量和交通荷载状况,利用轮载谱分析货车交通量和交通荷载状况,并推荐了江苏省内货车轮载和典型轮载比例;分析江苏省内三座跨江大桥的货车超载情况并给出了超载比例较大的车型。研究成果为泰州大桥钢桥面铺装设计研究提供了有力支持。

关键词: 跨江大桥     轮载谱     轮载类型     交通量     交通荷载    

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 631-644 doi: 10.1007/s11465-020-0599-x

摘要: The ever-increasing requirements for the scalable manufacturing of atomic-scale devices emphasize the significance of developing atomic-scale manufacturing technology. The mechanism of a single atomic layer removal in cutting is the key basic theoretical foundation for atomic-scale mechanical cutting. Material anisotropy is among the key decisive factors that could not be neglected in cutting at such a scale. In the present study, the crystallographic orientation effect on the cutting-based single atomic layer removal of monocrystalline copper is investigated by molecular dynamics simulation. When undeformed chip thickness is in the atomic scale, two kinds of single atomic layer removal mechanisms exist in cutting-based single atomic layer removal, namely, dislocation motion and extrusion, due to the differing atomic structures on different crystallographic planes. On close-packed crystallographic plane, the material removal is dominated by the shear stress-driven dislocation motion, whereas on non-close packed crystallographic planes, extrusion-dominated material removal dominates. To obtain an atomic, defect-free processed surface, the cutting needs to be conducted on the close-packed crystallographic planes of monocrystalline copper.

关键词: ACSM     single atomic layer removal mechanism     crystallographic orientation effect     mechanical cutting     Manufacturing III    

Multidisciplinary co-design optimization of structural and control parameters for bucket wheel reclaimer

Yongliang YUAN, Liye LV, Shuo WANG, Xueguan SONG

《机械工程前沿(英文)》 2020年 第15卷 第3期   页码 406-416 doi: 10.1007/s11465-019-0578-2

摘要: Bucket wheel reclaimer (BWR) is an extremely complex engineering machine that involves multiple disciplines, such as structure, dynamics, and electromechanics. The conventional design strategy, namely, sequential strategy, is structural design followed by control optimization. However, the global optimal solution is difficult to achieve because of the discoordination of structural and control parameters. The co-design strategy is explored to address the aforementioned problem by combining the structural and control system design based on simultaneous dynamic optimization approach. The radial basis function model is applied for the planning of the rotation speed considering the relationships of subsystems to minimize the energy consumption per volume. Co-design strategy is implemented to resolve the optimization problem, and numerical results are compared with those of sequential strategy. The dynamic response of the BWR is also analyzed with different optimization strategies to evaluate the advantages of the strategies. Results indicate that co-design strategy not only can reduce the energy consumption of the BWR but also can achieve a smaller vibration amplitude than the sequential strategy.

关键词: bucket wheel reclaimer     co-design     energy-minimum optimization     sequential strategy    

Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 595-614 doi: 10.1007/s42524-021-0173-1

摘要: Train speed profile optimization is an efficient approach to reducing energy consumption in urban rail transit systems. Different from most existing studies that assume deterministic parameters as model inputs, this paper proposes a robust energy-efficient train speed profile optimization approach by considering the uncertainty of train modeling parameters. Specifically, we first construct a scenario-based position–time–speed (PTS) network by considering resistance parameters as discrete scenario-based random variables. Then, a percentile reliability model is proposed to generate a robust train speed profile, by which the scenario-based energy consumption is less than the model objective value at α confidence level. To solve the model efficiently, we present several algorithms to eliminate the infeasible nodes and arcs in the PTS network and propose a model reformulation strategy to transform the original model into an equivalent linear programming model. Lastly, on the basis of our field test data collected in Beijing metro Yizhuang line, a series of experiments are conducted to verify the effectiveness of the model and analyze the influences of parameter uncertainties on the generated train speed profile.

关键词: robust train speed profile     percentile reliability model     scenario-based position–time–speed network     mixed-integer programming    

Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

《能源前沿(英文)》 2007年 第1卷 第2期   页码 125-128 doi: 10.1007/s11708-007-0015-9

摘要: By analyzing the challenges of China s energy supply, an excellent perspective of nuclear power development in the country has been described. Taking into account the near-, mid-, and long-term development requirements, a comprehensive, coordinated and sustainable nuclear power program is proposed. Thus, our national nuclear industry can not only catch up with the world s advanced level in proper time, but also possess enough stamina for sustainability.

关键词: development     excellent perspective     long-term development     comprehensive     national    

标题 作者 时间 类型 操作

A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn end mills

期刊论文

Numerical investigation of the influence of casting techniques on fiber orientation distribution in ECC

Chung Nguyen VAN; Hai TRAN THANH; Thuc Nhu NGUYEN; Jianchun LI

期刊论文

高温合金压气机盘锻件纵断面中铌分布的原位统计分布分析表征

王海舟,李美玲,庄景云

期刊论文

An automated arc spray tooling system for rapid die-making of large-sized automobile body panels

HE Zhong-yun, LU Bing-heng, WANG Yi-qing, HONG Jun, TANG Yi-ping

期刊论文

WEIS wheel speed real-time measuring method for VOSM

Mengyao PAN, Guixiong LIU, Xiaobin HONG, Tusheng LIN,

期刊论文

Experimental and CFD analysis of nozzle position of subsonic ejector

Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN

期刊论文

Simulation and analysis of grinding wheel based on Gaussian mixture model

Yulun CHI, Haolin LI

期刊论文

Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering

期刊论文

Lightening structure optimization on turbine wheel of vehicular turbocharger

ZHAO Junsheng, MA Chaochen, HU Liaoping

期刊论文

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

期刊论文

泰州大桥钢桥面铺装轮载谱研究

李洪涛,潘友强,张志祥

期刊论文

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

期刊论文

Multidisciplinary co-design optimization of structural and control parameters for bucket wheel reclaimer

Yongliang YUAN, Liye LV, Shuo WANG, Xueguan SONG

期刊论文

Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

期刊论文

Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

期刊论文