Volume 40,Issue 2,2017 Table of Contents

1 Parameter identification of constitutive models of rubber materials based on hyperstatic equations

XU Zhongming , YUAN Quan , ZHANG Zhifei , HE Yansong , HUANG Shenrong

2017, 40(2):1-9. DOI: 10.11835/j.issn.1000-582X.2017.02.001

[Abstract](1392) [HTML](389) [PDF 2.96 M](2188)

Abstract:
Great difficulty exists in the parameter identification of constitutive models of rubber materials because of the nonlinear large deformation characteristics of rubber materials. A new method based on hyperstatic equations was developed in order to improve the accuracy of parameter identification. A rubber bushing was analyzed with finite element (FE) approach, using the parameters identified with the developed method and the least square method. Then the two FE-predicted results were compared with test data. The results reveal that the identification method based on hyperstatic equations can precisely estimate the parameters of rubber material and its accuracy is obviously higher than that of the least square method. The efficiency and reliability of the developed method is validated.

2 Current situation and development trend of plug-in hybrid electricvehicle's energy management strategies

SU Ling , ZENG Yuping , QIN Datong

2017, 40(2):10-15. DOI: 10.11835/j.issn.1000-582X.2017.02.002

[Abstract](1843) [HTML](1396) [PDF 917.40 K](2716)

Abstract:
Domestic and foreign scholars has extensively and deeply researched into plug-in hybrid electric vehicle's energy management strategies, and good results of energy saving and emission reduction has been achieved. In order to further improve the performance of plug-in hybrid electric vehicle, it is necessary to summarize the research status of its energy management strategies and analyze its development trend. Firstly, we summarized and analyzed the power source's energy flow distribution method of plug-in hybrid electric vehicle, and then pointed out two problems that needed to be solved in the current plug-in hybrid electric vehicle's energy management strategies. The first problem is the influence of engine coolant temperature and catalytic converter temperature on fuel consumption and emission isn't considered, and the second one is the current energy management strategies only take drive power demand as input and the cab cooling/heating power demand is ignored. Finally, two future research directions were proposed. The first direction is the energy management strategy integrating engine coolant temperature and ternary catalytic converter temperature, and the second one is the strategy integrating cab's cooling/heating power demand.

3 Hierarchical control technology for large-span set-up room roof in deep

JIA Housheng , LI Guosheng , ZHANG Hui , JIANG Wenyuan

2017, 40(2):16-25. DOI: 10.11835/j.issn.1000-582X.2017.01.003

[Abstract](1042) [HTML](364) [PDF 4.79 M](1217)

Abstract:
The large-span set-up room roof in deep usually has poor self-stability, acute deformation and supporting difficulties. We took the set-up room support of 1105 large-mining-height panel in Zhaogu No.2 mine as research background, analyzed the roof failure mechanism and the key of roof control in different layers through field research, theoretical analysis and roof detection, put forward a hierarchical control technology dominated by lengthened bolt support, and stated the hierarchical control principle. According to this principle, the second tunneling supporting design of 1105 set-up room in Zhaogu No.2 mine was made, and the roof convergence as well as the roof fall and failure were monitored. The results indicate that the "anchor roof beam", which is collectively formed by lengthened bolt and middle layer roof, shows good stability. And roof of every layer is controlled effectively, which well ensures the safety of set-up room roof and normal service.

4 DEA efficiency analysis of energy in Chongqing under the constraint of green and low carbon economy

LI Jianbo , XIAN Xuefu

2017, 40(2):26-36. DOI: 10.11835/j.issn.1000-582X.2017.02.004

[Abstract](1453) [HTML](344) [PDF 1.17 M](1307)

Abstract:
Objectively evaluating the efficiency of input and output of the energy in Chongqing, exploiting the relationship between environment pollution, energy consumption and economic growth, and optimizing the energy structure, are the important issues for guiding energy consumption of Chongqing to the direction of green and low carbon and the important basis of policy-making for energy saving and pollution reduction, and strategy-making of energy development and economic planning. In this work, we scientifically grouped the energy input and economic and social output factors, and then used data envelopment analysis (DEA) to construct an energy demand structure equation and a DEA model. And a series of DEA empirical studies on energy consumption in Chongqing were conducted. The variation of scale efficiency of Chongqing energy input and output in different historical periods and different stages, the energy redundant input value (radial improvement and relaxation improvement), the scale effect value, the comprehensive technical efficiency value and the pure technical efficiency value were obtained, and then the effective production frontiers of DEA weak efficiency, DEA efficiency and DEA complete efficiency were determined. Based on these results, the energy structure from 2016 to 2020 in Chongqing was optimized. The research results can provide a scientific basis for the green and low carbon development of Chongqing and optimizing the its energy consumption structure in the 13th Five-Year Plan.

5 Characterization difference of coals with different spontaneouscombustion tendencies during oxidation stage

YU Minggao , YUAN Zhuang , CHU Tingxiang , GUO Pinkun , ZHENG Kai

2017, 40(2):37-44. DOI: 10.11835/j.issn.1000-582X.2017.02.005

[Abstract](1366) [HTML](390) [PDF 2.49 M](1168)

Abstract:
Low temperature oxidation experiments of three coal samples with different spontaneous combustion tendencies were carried out. Activation energies and characteristic temperatures of coal oxidation process conversion were obtained by the computational model based on the relationship between CO volume fraction and coal temperature change. With the experimental results of TG-DSC(theremogravimetric analysis-differential scanning calorimetry), the change laws of activation energy and oxidation characteristics of three coal samples in low temperature were analyzed. The results show that 1) during the low temperature oxidation, the CO generation amount, the oxygen consumption amount and the oxygen consumption rate increase with the enhancement of spontaneous combustion tendency. Temperature inflections that CO generation amount and oxygen consumption rate increase sharply are the same during the experiment of different coal samples. And the stronger the spontaneous combustion is, the lower the temperature inflection is, and the change of CO volume fraction shows obvious stages. 2) The change laws of activation energy of coals with different spontaneous combustion tendencies are significantly different. When coal temperature reaches the active temperature, activation energy decreases rapidly, and the mutation points of activation energy are corresponding to the conversion characteristic temperatures in coal oxidation process. 3) According to the characteristic temperature and the change law of activation energy, the low temperature oxidation process could be divided into four stages, namely surface oxidation, thermal oxidation, accelerated oxidation and deep oxidation.

LIU Jianping , JIANG Deyi , CHEN Jie , LIU Xinrong

2017, 40(2):45-51. DOI: 10.11835/j.issn.1000-582X.2017.02.006

[Abstract](1208) [HTML](372) [PDF 2.92 M](1358)

Abstract:
Using underground salt cavern for oil and gas storage is a common practice. Due to the characteristics of underground salt mines in China, which are rich in bedded salt rock, thin in terms of thickness and combined with high volume of insoluble non-salt rock, the shape control of single-well cavern construction is inevitably difficult and the construction takes a long time. Using experimental simulation construction of the horizontal salt cavern as a basic model, and taking the geological and physically mechanical conditions of salt caverns in Yunying, Hubei province into consideration, we numerically simulated the long-term rock creep effect under different buried depths with the twin-well cavern construction method. The simulation results show that the construction method is applicable, and the shape of cavern can be controlled through flow and fluid interface. It's also found during the same time in which rock creep takes effect, the deeper the cavern is buried, the higher the shrinkage rate of the cavern is, and the larger the plastic deformation zone around cavern becomes, which finally result in the shorter service life of the salt cavern for horizontal gas storage.

7 Precondition and influence factors of steel ladle interaction

HUANG Bangfu , TIAN Naiyuan , SHI Zhe , MA Zhiwei , ZHOU Xiaolei

2017, 40(2):52-59. DOI: 10.11835/j.issn.1000-582X.2017.02.007

[Abstract](1217) [HTML](323) [PDF 2.09 M](1289)

Abstract:
For further research on the precondition and the influence factors of ladle interaction among continuous casters, we took steel ladle of H steelmaking plant as the research object and analyzed the operation process and time of steel ladles. The relationship among turnover times, turnover numbers and cast numbers were analyzed. And the steel ladle's turnover process of 2 continuous casters with overlapping time of 50 min was simulated with Gantt chart. The simulation results show that the precondition of steel ladle interaction is the steel ladle no longer undertakes the transport task at 2# continuous caster and the empty ladle's ending time is prior to heavy ladle's starting time of 1# continuous caster. After researching the influence of overlapping time on ladle interaction, it's concluded that the precondition of steel ladle interaction is the cast number during overlapping time is less than the turnover number of steel ladle. By researching the influence of turnover cycle and casting time of single ladle on ladle interaction, it's showed the rational control and matching can raise the non-turnover number and probability of steel ladle interaction.

8 TCP flow time fairness in wireless network access point

JIANG Qiming , MI Chunqiao , YUE Guangxue , SHI Yuanquan , YAO Dunhong

2017, 40(2):60-65. DOI: 10.11835/j.issn.1000-582X.2017.02.008

[Abstract](1141) [HTML](573) [PDF 1.80 M](1264)

Abstract:
The time unfair phenomenon of up/downlink TCP(transmission control protocal) flow in wireless network access point was studied and the problem of congestion control in wireless network access was reported. A fairness scheduling algorithm for TCP flows was proposed in wireless network. The algorithm adopts the method of fast TCP flow transmission priority, which not only ensures the throughput fairness of TCP flow, but also solves the problem that slow TCP flow occupies too much channel time. And thus the time fairness of occupying channel of TCP flow was realized. Network simulation experiments show that the new fair scheduling algorithm has better performance than the traditional algorithm and it improves overall efficiency of network.

9 A new determination method of cloud point by resonance light scattering

WENG Chao

2017, 40(2):66-69. DOI: 10.11835/j.issn.1000-582X.2017.02.009

[Abstract](1074) [HTML](470) [PDF 1.22 M](1185)

Abstract:
The cloud point is one of the characters for non-ionic surfactants and plays an important role in practical application. A new method for the determination of the cloud point by resonance light scattering was proposed. The cloud point of a pyrrolidone sample was determined by the new method and the results were compared with those of UV spectroscopy method and dynamic light scattering method. The cloud point temperatures measured by the three methods were 34.3℃, 31.7℃ and 34.7℃, respectively. Experimental results indicate that the cloud point temperature measured by resonance light scattering is very close to those by UV spectroscopy and dynamic light scattering.

10 Short-circuit current calculation of inverter interfaced distributed generator based on voltage control in distribution network

XIE Weibing , LIU Min , ZHOU Xiaoxia , JING Yong , YE Ling , WANG Qianggang , ZHOU Niancheng

2017, 40(2):70-79. DOI: 10.11835/j.issn.1000-582X.2017.02.010

[Abstract](1116) [HTML](328) [PDF 3.65 M](1331)

Abstract:
The distribution of power flow and short-circuit current is changed by the distributed generation embedded in distribution network, and its short-circuit current affects the operation of protection and reclosing devices. The fault response characteristics of voltage controlled inverter interfaced distributed generator (ⅡDG) were studied, and the relationship between ⅡDG three-phase power and power components in the positive and negative sequence networks under asymmetrical fault condition were also analyzed. Then a sequence component model of voltage controlled ⅡDG for short-circuit current calculation was established. The fault current change law and recursion formula were gained according to the interaction between the ⅡDG and the sequence networks, and consequently the iterative algorithm of symmetrical components for short-circuit current calculation of distribution network with voltage controlled ⅡDG was proposed. The correctness of the proposed method was verified by the electromagnetic transient model of voltage controlled ⅡDG in PSCAD/EMTDC simulation software.

11 Application of contragradient law and large increment method to the analysis of complex frame structure

CHEN Zhaohui , WANG Xurong

2017, 40(2):80-90. DOI: 10.11835/j.issn.1000-582X.2017.02.011

[Abstract](1339) [HTML](997) [PDF 1.61 M](1100)

Abstract:
The large increment method(LIM) is an iterative method based on the force method and the generalized inverse matrix theory. In the nonlinear initial application of trusses and rigid frames, LIM reaches the same solution as the displacement-based finite element method with the same number of iterations or even less. Aiming at the complex bar structure, we discussed the application of LIM and contragradient law to the complex frame structure, established the LIM basic formula in frame structure and proposed the analysis approaches for complex boundary condition and composite joints. The illustrative example of linear elastic problem clearly reveals that the accuracy and the efficiency of LIM are the same as those of displacement-based finite element method. The method is also applicable to elasto-plastic problems without considering the plasticity of the support itself, which lays the foundation for LIM in the elasto-plastic analysis of complex bar structures.

12 A uniform calculation method of the skeleton curve of equal sectional concrete filled steel tube columns

OU Zhijing , CHEN Shengfu

2017, 40(2):91-100. DOI: 10.11835/j.issn.1000-582X.2017.02.012

[Abstract](1067) [HTML](328) [PDF 2.80 M](1301)

Abstract:
The calculation methods of skeleton curve of equal sectional CFST (concrete filled steel tube) columns with flat or inclined lacing tubes were introduced and analyzed. It's found the seismic behavior of equal sectional CFST columns has generality, no matter their lacing tubes are flat or inclined. To find out a uniform calculation method of skeleton curve of equal sectional CFST columns on the base of hysteretic model of CFST single tube column, we explored the calculation methods of elastic stiffness, horizontal peak load, peak load displacement and fall-period stiffness, and then carried out a verification experiment with OpenSEES program by taking the laced column pier of Ganhaizi bridge as an example. Research results indicate that the calculated values of the new calculation method are coincident well with the test and the numerical results. Finally the uniform method which can be adapted to engineering application is provided, and it can provide references for the calculation theory and relevant criteria of CFST structures.

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