Volume 41,Issue 6,2018 Table of Contents

1 Tool wearmonitoring based on improved artificial bee colony algorithm and extreme learning machine

GUO Yijun , ZHOU Jie , WANG Shilong , YI Lili , KANG Ling , GAO Bo

2018, 41(6):1-8. DOI: 10.11835/j.issn.1000-582X.2018.06.001

[Abstract](898) [HTML](368) [PDF 3.06 M](871)

Abstract:
To improve the real-time monitoring accuracy of the actual wear of cutting tools, Extreme Learning Machine (ELM) algorithm was applied to establish the tool wear model. An Improved Artificial Bee Colony (IABC) algorithm with a virtual bee was proposed to tune the input layer weights as well as the hidden layer biases in ELM. Time-domain analysis and Empirical Mode Decomposition (EMD) were used to extract the time-domain features and energy ratio of Intrinsic Mode Function (IMF) from cutting force signal, vibration signal and acoustic emission signal, and the features sensitive to tool wear were selected as the monitoring features. Then the tool wear value could be calculated through the trained model. The result show that the optimized ELM can predict the tool wear value accurately, and has a simpler network structure. Meanwhile, the IABC algorithm also shows a better searching ability.

2 Optimization strategy of wet clutch based on response surface test design

LIU Wen , WANG Qingsong , LIN Tengjiao , WEI Jing , LI Rui

2018, 41(6):9-23. DOI: 10.11835/j.issn.1000-582X.2018.06.002

[Abstract](561) [HTML](360) [PDF 9.96 M](1005)

Abstract:
In order to improve wet clutch's reliability, a parametric finite element model with the diameter of six outlet pipes as variables was established, and the heat-flow coupling analysis was carried out based on CFD. According to the characteristics of heat flow field, optimization strategy was designed. The sampling principle of CCD was analyzed, the formulas for the factorial coefficient, the number of sample points, the level and corresponding test times were deduced respectively, and applied to the response surface test design. Single factor simulation tests were adopted to determine the minimum axial displacement of clutch plates as the target variable, and test point arrangement table was further arranged. Based on least square method, the response surface model was fitted, three optimization schemes were obtained by different tools. The results show that, in the optimum scheme, the target variable increases by 38.472%, the error between forecast and actual simulation is 7.291%, and the thinnest oil-layer thickness increases by 18.828%.

3 Fuzzy evaluation of assembly design scheme based on attribute value reduction of rough sets

ZHOU Wei , XIAO Liming , HUANG Guangquan , JU Pinghua , RAN Yan

2018, 41(6):24-34. DOI: 10.11835/j.issn.1000-582X.2018.06.003

[Abstract](672) [HTML](299) [PDF 2.26 M](863)

Abstract:
In order to evaluate the assembly design plan reasonably and quickly, and ensure the excellent implementation of the assembly program, fuzzy evaluation method for assembly design was proposed. Firstly, the evaluation index system of assembly design was put forward on the basis of investigation and related literature search, the evaluation index was simplified, deleting the redundant indexes and retaining the necessary indexes with the aid of rough set theory and expert knowledge, and the quantification method of index was defined.Then, the importance of each evaluation index was analyzed, and the fuzzy weight of the comprehensive evaluation set was calculated. Finally, according to the property of the necessary index value and weight, the comprehensive evaluation of the feasible assembly design scheme was realized by applying technique for order preference by similarity to ideal solution,and the correctness of the method was proved by comparing with the evaluation results of fuzzy analytic hierarchy process and fuzzy comprehensive evaluation. An assembly sequence optimization process of a machine tool transmission system in an enterprise was quoted as an example to illustrate the feasibility of the proposed approach.The result shows that the fuzzy evaluation method of assembly design scheme is reasonable, and the optimized scheme has higher precision and efficiency.

4 Research on sharing platform model for manufacturing equipment in cloud manufacturing

YI Lili , GAO Bo , KANG Ling

2018, 41(6):35-41. DOI: 10.11835/j.issn.1000-582X.2018.06.004

[Abstract](743) [HTML](349) [PDF 6.25 M](850)

Abstract:
To meet the needs of scientific research and teaching, a large quantity of manufacturing equipment are purchased by universities in China,and yet, a considerable amount of manufacturing capacity is wasted. To increase the usage of these equipments, a normalied model with double architecture was established with the aid of the information expression and organization of manufacturing requirements as well as the description of the manufacturing equipment's capability, and an open cloud manufacturing platform for manufacturing equipment was developed. In addition, a user interface strategy based on knowledge engineering was proposed to improve usability of the normalization model in cloud manufacturing platform. Finally, a case study showed that the model and the platform were valid.

5 Application of aerodynamic simulation to the development of motorcycle styling

ZHOU Ying , ZHANG Lipeng , YAN Yan , SHI Chuntao

2018, 41(6):42-49. DOI: 10.11835/j.issn.1000-582X.2018.06.005

[Abstract](765) [HTML](679) [PDF 6.18 M](905)

Abstract:
The aerodynamic characteristics of motorcycle influent the power performance, fuel economy and operation stability of motorcycles directly. Considering the absence of special wind tunnel for motorcycles in the domestic and road coasting test doing not apply to all types of motorcycle, aerodynamic simulation method was applied in the development process of a new touring styling by analyzing the aerodynamic characteristics of real vehicle model. Basing on that, the optimization design was made and then simulations were made respectively with two windscreen installation angles provided. The simulation results show that drag coefficient C_d is reduced by the optimization scheme and the aerodynamic characteristics comparison between the two installation schemes provide the reference for further style selection.

6 Fabrication and thermal expansion property study of graphene/epoxy nanocomposites

HU Rongjie , NING Youjun , XIAO Teng , LEI Ling , Alamusi , HU Ning

2018, 41(6):50-57. DOI: 10.11835/j.issn.1000-582X.2018.06.006

[Abstract](906) [HTML](1040) [PDF 3.77 M](913)

Abstract:
Graphene/polymer nanocomposite material has drawn great attentions because of its outstanding physical and mechanical properties. However, study on the fabrication and thermal expansion behaviors of graphene/polymer nanocomposites is far from satisfaction,and this paper is concerned with the problem. Firstly, techniques including ultrasonic dispersion, mixing and stirring, and isothermal curing, etc., were used to fabricate graphene/epoxy composites. The fabrication technology was progressively optimized and finally more mature. In the experiment, the mass fraction of graphene in the composites was 1.0%~5.0%. Thereafter, the conductive property of the fabricated composites was tested,and the thermal expansion property was measured and analyzed within the temperature range of 30℃ to 120℃. The results indicated that, by adding graphene, conductive polymer composites can be obtained. The thermal expansion coefficient of the polymer can be effectively reduced, and it could be reduced to a greater degree with a larger content of graphene added. The present work provides possibility for future fabrication of conductive polymer composites with zero thermal expansion.

7 Pore distribution characteristics of dredged sludge cementation body solidified with fly ash and mineral power under alkali stimulated conditions

SUN Xiuli , WANG Shuting , YAO Jun , LIU Wenhua , HAN Yitian , LI Zhiqiang , TAN Yusheng

2018, 41(6):58-65. DOI: 10.11835/j.issn.1000-582X.2018.06.007

[Abstract](659) [HTML](478) [PDF 3.14 M](896)

Abstract:
Curves of mercury injection and pore distribution density of alkali-activated dredged sludge cementation body solidified with fly ash and mineral powder were obtained by mercury intrusion porosimetry (MIP) test, and its shear strength indexes were measured by direct shear test and bearing ratio test. It's proposed to use pore distribution coefficient to characterize the uniformity of pore distribution of the cementation body, and the quantitative relationships between the pore distribution coefficient and the shear strength index and CBR values were established, respectively. The results show that the pore distribution coefficient of the cementation body is closely related to its mechanical indexes. The smaller the pore distribution coefficient is, the more uniformly the pores of the cementation body distributes, and the higher the shear strength index and CBR are, whereas the bigger the pore distribution coefficient is, the less uniformly the pores of the cementation body distributes, and the lower the shear strength index and CBR are.

8 Friction and wear properties of 10CrMn2NiSiCuAl icebreaker steel plates effected by temperature

WANG Dongsheng , CHANG Xueting , WANG Shiyue , SUN Shibin , YIN Yansheng

2018, 41(6):66-75,90. DOI: 10.11835/j.issn.1000-582X.2018.06.008

[Abstract](726) [HTML](496) [PDF 10.82 M](924)

Abstract:
Dry reciprocating friction and wear properties of a novel icebreaker steel (10CrMn2NiSiCuAl), which is co-developed by our group and BaoSteel Co., Ltd, were investigated using a UMT-3 Tribolab multi-specimen tester at different temperature. In this study, the wear scar morphologies and friction cross sections of the tested samples before and after the friction tests were recorded by coherence Scanning Interferometry.The surface morphologies, composition of worn surfaces and wear debris were characterized by scanning electron microscope, energy dispersive spectrometer and X-ray diffusion. Results show that the friction and wear properties are obviously affected by temperature. The wear mechanism is mainly fatigue failure accompanied with oxidation and adhensive wear at 20℃,which turn to abrasive wear and fatigue wear when the temperature decreases. The transition layer on the worn scar formed by Fe₂O₃ and Fe₃O₄ reduces the friction coefficient and wear rate. The declamation and spherical wear debris occur on the worn surface when the temperature decreases to -20℃, which aggravates the wear rate quickly.

9 Experimental study of displacing & replacing methane in low permeability coal seam by injecting liquid carbon dioxide

MA Li , WEI Gaoming , WANG Shibin , LI Zhenbao , LIU Xinmin

2018, 41(6):76-83. DOI: 10.11835/j.issn.1000-582X.2018.06.009

[Abstract](622) [HTML](294) [PDF 3.90 M](840)

Abstract:
This paper is to solve the gas drainage problem of low permeability coal seam. Based on the characteristics of liquid carbon dioxide with low temperature, viscosity, percolation resistance and phase change pressurization, the liquid carbon dioxide enhanced methane recovery technology was proposed to improve the gas drainage efficiency. Liquid carbon dioxide injection test was carried out at Sangshuping No.2 mine shaft,Hancheng mining area, and by which injection process was developed, the key parameters were determined and the methane extraction efficiency influenced by carbon dioxide was examined. The results show that the pressure of injecting is fluctuated. Initially, injecting pressure rises fast and then keeps stable when rising to 2.5 MPa.The flow rate of injection maintains from 0.6 m³/h to 1.4 m³/h and the total cumulant of liquid carbon dioxide is 6.0 m³. The concentration of carbon dioxide in the test borehole is taken as index, and it's found that the influence radius of the test is 18 m. The methane concentration and the purity in the test area are 2.5 and 3.5 times of those in the original data respectively, which proves the proposed technology enhances the gas extraction efficiency.

10 Formation of bromate in aqueous solution in the presence of Br^- under ultrasonic irradiation

YAO Juanjuan , LIU Wei , ZHOU Lingxi

2018, 41(6):84-90. DOI: 10.11835/j.issn.1000-582X.2018.06.010

[Abstract](876) [HTML](326) [PDF 1.44 M](677)

Abstract:
Formation of bromate(BrO₃^-) in aqueous solution in the presence of Br^- under ultrasonic irradiation was investigated. The results show that BrO₃^- formed by a series of reactions between hydroxyl free radical (·OH) generated by ultrasonic cavitation and Br^-. The total BrO₃^- yield increases with the increase of the initial concentration of Br^-. While the yield ratio of BrO₃^- to Br^- decreases with the increased initial concentration of Br^-. The yield of BrO₃^- at different frequencies follows the order 400 > 600 > 800 > 200 kHz. When the ultrasonic energy density increases from 0.06 W/mL to 0.19 W/mL, the formation rate of BrO₃^- increases first and then decreases. BrO₃^- formation rate decreases with the increase of pH.

11 Application of ACPSO-BP neural network in discriminating mine water inrush source

XU Xing , LI Yuanzhi , TIAN Kunyun , ZHANG Ruilin

2018, 41(6):91-101. DOI: 10.11835/j.issn.1000-582X.2018.06.011

[Abstract](859) [HTML](338) [PDF 2.78 M](776)

Abstract:
The continuous mining in the coal mine has made the water quality characteristics of each aquifer become more complex and more similar, and it is difficult to establish a precise discriminating model by using classical mathematical methods. The BP neural network with nonlinear mapping function can overcome the above problems, but it still has the disadvantage of being easy to fall into local optimization and having slow convergence speed. We introduced the "premature" judgment mechanism, Tent chaos map and adaptive weight adjusting strategy into particle swarm optimization algorithm, establishing a water inrush discrimination model on the basis of adaptive chaos particle swarm optimization algorithm and BP(ACPSO-BP) neural network. The application results show that compared with the BP neural network model and the model based on standard particle swarm algorithm and BP(SPSO-BP) neural network, the ACPSO-BP neural network model has faster convergence speed, higher accuracy and stronger generalization.

12 Reasonable layout of drainage boreholes based on anisotropic permeability in coal seam

ZENG Chunlin , YUE Gaowei , WANG Binbin , HUO Liupeng

2018, 41(6):102-114. DOI: 10.11835/j.issn.1000-582X.2018.06.012

[Abstract](650) [HTML](406) [PDF 8.96 M](1022)

Abstract:
Coal seam degasification by in-seam drilling borehole is one of the popular techniques for coal mine methane (CMM) control. Generally, the more borehole numbers for a specific drainage area, the shorter drainage time but the higher drainage cost. In order to resolve the contradiction between borehole numbers and drainage duration, in-situ tests of effective gas drainage radius were conducted continuously in an anisotropic coal seam for 180 days at Jiulishan coal mine in China, and coal permeability was measured associated with bedding and cleat structures, and then gas-solid coupled seepage model was built to simulate the change rules of effective drainage radius in an anisotropy coal seam using finite-element based Comsol package. The results indicate that the coal permeability parallel to the bedding plane in butt cleat direction is 2.6 times as high as that perpendicular to the bedding plane. And effective drainage radius parallel to the bedding plane in butt cleat direction will get much larger than that perpendicular to the bedding plane with the increase of drainage duration and shows exponential relationship with gas pre-extraction time. The numerical results of simulated tests are consistent with those of field tests. Based on numerical results, the ellipse influence area of borehole in an anisotropic coal seam is proposed, and the relativity of effective drainage radius with drainage time is found. On the basis of these findings the proper in-seam borehole arrangements for a specific mining panel at different drainage duration are determined.

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