Table of Content

25 September 2018, Volume 46 Issue 9

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Mechanical Engineering

Cycloidal Gear Tooth Profile Modification of RV Reducer Based on Backlash-Optimized

LU Longsheng ZHANG Feixiang WAN Zhenping TANG Yong

2018, 46(9):  1-8.  doi:10.3969/j.issn.1000-565X.2018.09.001

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In order to optimize the backlash of the RV reducer, the factors affecting the backlash are classified from the angle of the part error based on the two stage structure and the torque transmission path of the RV reducer. Taking the RV-40E reducer used in industrial robot as an example, the sensitivity and weight of the backlash are calculated. Among them, the cycloidal gear profile modification has large sensitivity. In order to reduce the gear side clearance caused by the cycloid gear modification, a modification method of the cycloidal gear tooth profile based on the compensation of deformation is proposed. On the basis of equidistant & radial-moving modification, the deformation of the pin gear at rated load is compensated for the cycloidal gear tooth profile. The backlash optimization of the RV reducer is realized without changing the radial clearance of cycloidal drive. The virtual prototype of RV-40E reducer is set up, and the simulation verification is carried out in the SolidWorks Motion. The results show that, with the optimization of backlash, the backlash of virtual prototype is 0.25 '~0.98', which is lower than that of the virtual prototype with equidistant & radial-moving modification (0.54 '~1.22'). The cycloidal gear tooth profile modification method based on the compensation of deformation can significantly reduce the backlash of the RV reducer.

The Comprehensive Performance Evaluation of Multi – Way Valve for the Topology Design of the groove structure

WANG Anlin TANG Jiangwei ZHANG Xiaolu

2018, 46(9):  9-16.  doi:10.3969/j.issn.1000-565X.2018.09.002

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Aiming at the problem of fluid - solid coupling topology design for the groove structure under the condition of open - loop condition which needs to meet the performance requirements in a variety of operating conditions, the article proposed a comprehensive performance evaluation method for multi - way valve topology design of the groove structure. In this paper, the hydraulic excavator swing-valve is the object, the spool reversal process is divided into fretting, proportional speed control and full opening sections. The paper set the topology of the groove structure parameter as the design variable and set the performance evaluations of the three opening sections as a goal, finally constructed the topology optimized design model of the groove structure for the comprehensive performance evaluation of multi – way valve which needs to meet the performance requirements in a variety of operating conditions. After verifying that the CFD simulation results of the multi-way valve are basically consistent with its experimental results, the simulation results of the above optimization model are simulated. The results show that the steady state comprehensive performance corresponding to the topology of the optimized structure is significantly improved, which indicates that the proposed method is effective for the topology design of multi - way structure which needs to meet the complex conditions and has the reference value.

Trajectory Planning for Crane's Trolley to Suppress Residual Swing of Payload

LIU Huasen CHENG Wenming LI Yinqi

2018, 46(9):  17-23.  doi:10.3969/j.issn.1000-565X.2018.09.003

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In view of the problem of an under actuated overhead crane’s payload swing caused by the inertia force, the trajectory planning of trolley was put forward to suppress the payload residual swing. The dynamic model of a crane system with damped oscillation was established, the method of phase plane analysis was used to study residual swing of the payload which are affected by the three different acceleration curves of the trolley. The Lyapunov function based on energy control method was used to dynamically design the acceleration curve of the trolley in real time. The simulation results show that the trajectory planning based on energy control method can effectively restrain the residual vibration of the overhead crane, and the acceleration curve of the trolley is smoother. When the trolley acceleration direction are same with the payload swing direction, the larger the trolley’s acceleration is, the faster the payload normalized energy decrease. The proposed control method can suppress the payload swing angle to the allowable value in 7.9s when the initial angle of payload is 0.087 rad.

Flow Nonlinear Compensation Control for Electro-hydraulic Servo Shaking Table

WEI Wei LIU Xingbao KONG Jinxing HUANG Wen HAN Junwei

2018, 46(9):  24-29,72.  doi:10.3969/j.issn.1000-565X.2018.09.004

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In order to reduce the distortion of acceleration vibration signal caused by the flow nonlinearity on electro-hydraulic servo shaking table, a control strategy based on the nonlinear compensation of flow is presented. Nonlinear flow equations of two valve cavities are built through the throttle equation. Combined with the hydraulic continuity equation and force balance equation, a nonlinear model of electro-hydraulic servo shaking table is established. According to the Taylor equation near the steady state point, the linear control model of the nonlinear hydraulic system is also given. Considering the maximum dynamic output force, a nonlinear compensation function related to the load pressure is introduced, which makes the flow of the compensated servo valve linearly with the spool displacement. The simulation and experimental results show that the nonlinear flow compensation control method can effectively reduce the acceleration distortion and improve the tracking accuracy of the vibration signal.

Inverse Kinematic of Six-axis robots based on R* (3,0,1) Geometric Algebra

DU Juan WU Hongtao YANG Xiaolong CHEN Bai CHENG Shili

2018, 46(9):  30-35.  doi:10.3969/j.issn.1000-565X.2018.09.005

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The Geometric algebra model R^* (3,0,1) combines the benefits of dual quaternions and conformal geometric algebra, i.e., dual quaternions can compute faster while comformal geometric algebra have same translation algorithm for points and planes as well as have algorithm to compute sign distance between points and planes. A new inverse kinematic of industrial robots algorithm is proposed based on R^* (3,0,1) model, i.e., the unique solution of inverse kinematic of industrial robots is determined by the sign distances between joints and three singular planes, and the sign distances can be computed by R^* (3,0,1) model. This new algorithm can find unique solution without comparing a preferred one which is widely applied in general inverse kinematic solution. This new algorithm has advantages, such as be able to compute the sign distance to the singular planes, simple, high speed to compute unique inverse kinematic solution, effectively when applied to practical robot motion control. This algorithm is numerical verified on PUMA 560.

Architecture & Civil Engineering

Prestress Optimization of Suspended Dome Structures Based on Mixed Intelligent Optimization Algorithm#br#

JIANG Zhengrong LIN Quanpan SHI Kairong RUAN Zhijian LU Junfeng LUO Bin

2018, 46(9):  36-42.  doi:10.3969/j.issn.1000-565X.2018.09.006

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Plant Growth Simulation Algorithm (PGSA) is a new intelligent algorithm based on the plant phototropism mechanism——morphactin concentration theory, which has efficient searching ability. Particle Swarm Optimization (PSO) is a heuristic optimization algorithm derived from bird swarm foraging, which has the advantages of simple rules and high robustness. By analyzing the basic principle of PGSA, it is pointed out that the selection of different initial growth points will affect whether PGSA can converge to the global optimal solution. Therefore, a new mixed strategy (PGSA-PSO mixed intelligent optimization algorithm) is proposed. First, the excellent initial growth points are selected based on the high robustness of PSO. Then based on the efficient search ability of PGSA, the final global optimal solution is obtained. A numerical example is given to verify that PGSA-PSO effectively improves the global search ability of PGSA. Furthermore, PGSA-PSO is used to analyze the typical prestressing optimization problem of suspended dome structures. The result shows that PGSA-PSO has a better optimization effect. Consequently, it has good feasibility and effectiveness in structural optimization problem.

A DDBD Seismic Design Method Based Double Substitute Structures

JIAN Bin MING Yanghua LEI Chaoyi TANG Tiantian

2018, 46(9):  43-50.  doi:10.3969/j.issn.1000-565X.2018.09.007

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A new concept of“double substitute structure”was established, combining the new concept with the basic iterative process, a new direct displacement based seismic design method considering global reliability was proposed.This new iterative design method use“relative reliability theory”to determine the displacement target corresponding to the given performance objectives, and transform the displacement target into corresponding base shear target precisely by“double substitute structure”, then calculate the exact designing base shear force to finish the iterative seismic design process by introducing a correction factor. The calculation examples showed that the new direct displacement based seismic design method can accurately control the displacement response of structure in the sense of global reliability.

Materials Science & Technology

Characterization of Interfacial Bonding for HB-FRP Strengthened Concrete Beams#br#

GAO Lei ZHANG Feng LIU Jiaqi LIU Guanzhi LU Xiaorui

2018, 46(9):  51-59.  doi:10.3969/j.issn.1000-565X.2018.09.008

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The combined effect of various contact interfaces of HB-FRP reinforced concrete leads to more complex interfacial bonding properties. Based on the experimental study, the HB-FRP numerical model was established which considering the plastic damage of concrete and interfacial bonding. The load-slip relationship, the interface strain distribution, the bond-slip relationship and the interfacial failure mode were compared and analyzed. The relationship between the number of FRP layers and the spacing of steel fasteners was analyzed. The results show that the numerical model can reliably reflect the bonding properties of HB-FRP reinforced interface, and HB-FRP reinforcement can effectively inhibit the development of debonding. The bond-slip relationship at the steel fastener is characterized by the typical trilinear shape of elastic rise, softening decrease, residual platform. The bond stress is finally stabilized rather than reduced to zero. Concrete failure surface at the steel fastener is "wedge-shaped" where the debonding thickness is greater than that of ordinary FRP bonding. Tensile strength increases after FRP thickness exceeds 5 layers. Tensile strength will not continuously increase as the spacing between steel fasteners decreases. When the spacing between steel fasteners is 250mm, the reinforcement efficiency of HB-FRP reinforcement mode can be fully utilized, which is 4.2 times that of ordinary FRP.

Architecture & Civil Engineering

Simulation Of Acoustic Environment In The Cave-style Ancient Stages

HUANG Wuqiong LU Yigang

2018, 46(9):  60-65.  doi:10.3969/j.issn.1000-565X.2018.09.009

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Abstract: Referring to the figure, structure and volume of a cave-style ancient stage among the Chaoshan Temple in Shanxi, five ancient stage models have been built. The computation space is 14.42m×15.68m×5.88m. Considering the wall's materials in the ancient stage, the models' boundary consists of rigid boundary and PML absorbing boundary conditions. Through the Finite-difference Time-domain method by using the MATLAB software, impulse responses of the receiving points in the five models have been calculated, which have been in spectral analysis. The results show that cave-style ancient stages can strengthen the sound's definition, satiety and sense of reverberation and so on, which can amplify sounds at some frequencies.

Materials Science & Technology

Wind tunnel tests on drag coefficients of multiple-insulator strings

YOU Yi YAN Zhitao LI Xinmin ZHONG Yongli HUANG Hanjie

2018, 46(9):  66-72.  doi:10.3969/j.issn.1000-565X.2018.09.010

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The wind tunnel tests were carried out to obtain the variation law of the drag coefficient of suspension porcelain insulator strings and suspension composite insulator stings with different wind velocities, wind attack angles, bundle spaces. The test models are made of the actual insulator strings and have the real rough surface. Test results show that it is unreasonable to calculate the wind load of the common and composite insulator strings with a same drag coefficient in the codes. In the two types of multiple-insulator strings, the range of the wake interference angle between the windward insulator strings and the leeward insulator strings is different. The leeward insulator strings is obviously shielded by the windward insulator strings. The shielding effect of the windward insulator strings should be considered at different wind attack angles. In the multiple-insulator strings, the variation of the bundle space has an obvious influence on the drag coefficient of the leeward insulator strings. The drag coefficient of the leeward insulator strings increases with the increase of the bundle distance. The influence degree of the drag coefficients of the leeward composite insulator strings caused by the variation of bundle space is greater than that of suspension porcelain insulator stings.

Traffic & Transportation Engineering

A Decision Making Model of College Students' Red Light Behavior Based On The Theory Of Planned Behavior

MA Yingying LU Siyuan

2018, 46(9):  73-81.  doi:10.3969/j.issn.1000565X.2018.09.011

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This paper proposed a decision-making model of college students running on red signal using the theory of planned behavior considering the characteristics of urban road traffic environment in China. Firstly, six scenarios of road crossing are proposed according to traffic flow, road width and central safety island. Secondly, questionnaire on each scenario was designed according to the theory of planned behavior and the behavioral experience variable. More than 400 college students in Guangzhou were involved in the survey, and valid samples are 397, with an effective rate of 91.75%. The data tests show that the survey data has a good performance on reliability, validity and internal consistence. Finally, structural equation modeling (SEM) is used to analyze college students crossing behavior in six scenarios, and six structural path diagrams are obtained. The results show that the attitudes towards crossing on red signals and the new behavioral experience have no significant correlation to behavioral intention, however, subjective norms and perceived behavioral control are significantly related to behavioral intention. The perceptual behavior control is a powerful predictor of behavioral intention, which can not only predict behavioral intention, but also act directly on actual behavior.

A model of area dynamic allocation and guidance of parking space with the minimum total parking cost

LU Kai LIN Maowei DENG Xingdong XU Guanghui XU Jianmin

2018, 46(9):  82-91,98.  doi:10.3969/j.issn.1000565X.2018.09.012

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Several factors of parking behavior, such as walking distance, parking fees, parking willingness, were considered comprehensively in this paper. The parking cost was decomposed into the cost of driving time, walking time, and parking fees. The definition and calculation method of virtual cost considering driver's willingness were given, and the sensitivity analysis of psychological impedance of walking distance and parking fee were conducted. Then the constraints of parking guidance control variables were determined, and the model of area dynamic allocation and guidance of parking space was established which minimized the total virtual parking cost of parking guidance system. The example analysis shows that this model can formulate the reasonable scheme of dynamic allocation and guidance of parking space considering the overall parking demand of the whole area. Compared with the broadcast parking guidance method, this method can decrease the phenomenon of looking for parking lots repeatedly and reduce the total actual parking cost of the whole area, especially when parking space is in tension.

A Dynamic Allocation and Guidance Model for Parking Spaces with Minimum Total Parking Costs#br#

LIU Zhongbo ZHAO Xiaohui

2018, 46(9):  92-98.  doi:10.3969/j.issn.1000565X.2018.09.013

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Abstract: The main intersection signal setting standard and basis are obtained through the establishment of microscopic traffic model, but the complexity of model calibration and calculation result in poor reliability of the data information, so it does not apply to the actual situation. Therefore, this paper directly using the data of the actual collection, the FCM( Fuzzy C-Means) clustering method is adopted to identify the roundabouts traffic state according to the headway changes inner and outer ring road traffic flow to provide the time basis of signal control for traffic managers. Finally, the method is verified on the VISSIM platform. The results show that the method can accurately distinguish the running state of the intersection traffic, provide reliable signal control basis for traffic management.

Study of the Horizontal and Vertical Combination of the Split-end of the Exit Ramp

ZHANG Chi ZHANG Hong QI Chen BAI Haochen GAO Jianrong HOU Yudi

2018, 46(9):  99-108.  doi:10.3969/j.issn.1000565X.2018.09.014

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In order to study the safety of diverting ramp shunting nose end of interconnected interchange under the conditions of different vertical and longitudinal lines. The dynamic simulation analysis of the passenger car is carried out. The vehicle model, the road model and the driver's preview trajectory model are established. By changing the radius of the circular curve and the longitudinal gradient of the diverting nose, simulating the driving conditions under different conditions, the horizontal alignment and longitudinal profile of the diverting nose were studied respectively. The response output of the lateral acceleration of vehicles under different working conditions is obtained, and the influence of different linear parameters on the safety of the diverting nose end is analyzed. The research results show that: at ramp outlet, the safety of long transition curve with small radius circular curve combination is superior to that of short transition curve with large radius circular curve combination. When the design speed of the main line is 120km/h and the longitudinal slope is -5%, the maximum lateral acceleration of the vehicle is 0.58g, and the vehicle sideslip is more dangerous at this time. It is suggested that the longitudinal slope of the diverted nose is less than 4% in the design. In order to ensure the safety of the shunting nose end, when the design speed of the main line is 120km/h, the radius of the circular curved nose round curve is 350m, and the longitudinal slope should be less than -3.5%. And the radius of the circular curve is 300m, and the longitudinal slope should be less than -3%. When the design speed of the main line is 100km/h, the radius of the circular curved nose round curve is 300m, the longitudinal slope should be less than -4%, and the radius of the circular curve is 250m, then the longitudinal slope should be less than -3.5%.

Optimization Research on Cross-section of Intercity EMU Body Based on LES

HUANG Zundi LIANG Xifeng CHANG Ning YIN Zhichun HUANG Yuming ZHENG Jiongjie MO Guangxing

2018, 46(9):  109-115.  doi:10.3969/j.issn.1000565X.2018.09.015

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The pressure data of the body surface on CRH6 intercity EMU were recorded through wind tunnel test in a certain percentage. Based on the calculation model of CRH6 intercity EMU, the O-Block structure grid was generated by ANSYS ICEM software. The steady-state data were calculated by using the k-epsilon two-equation turbulence model and the Large Eddy Simulation method was used to calculate the unsteady state data. The error between experimental data and simulation data was within 5%, and met the engineering accuracy requirements. Based on the above simulation algorithm, the three parameters of the transition arc of the roof and the side wall, the transition arc of the side wall and the under frame and the height of the widest vehicle body are the optimization variables, and the smallest overturning moment of the vehicle body is optimization target. At last, the reasonable cross section parameters of the vehicle body are obtained. Research results provide the theoretical basis for the design of CRH6 intercity EMU.

Study of Combination Damping Characteristics Effect of High-Speed Train Damper#br#

JIN Tianhe LIU Zhiming REN Zunsong LI Xiang

2018, 46(9):  116-124.  doi:10.3969/j.issn.1000565X.2018.09.016

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Abstract: Aiming at the situation that there are many types of rail vehicles in China and the parameters of different types of shock absorbers are quite different, the damping characteristics effect of the shock absorbers are studied. Using the dynamic simulation software SIMPACK to establish the vehicle system dynamics model, joining the measured orbit incentive of line of Wuhan-Guangzhou and considering the nonlinear relationship of the vehicle system, the dynamic performance index is calculated at the running speed of 300 km/h, and analysis of the effect of the combined damping of anti-yaw damper and secondary lateral damper on vehicle dynamic performance. The results show that reasonable combined damping parameters of anti-yaw damper and the secondary lateral damper can obviously improve the vehicle's dynamic performance. The stability of the vehicle are mainly affected by the damping of anti-yaw damper, and the influence of the secondary lateral damper is small. It is suggested that the selection of high-speed vehicle dampers should consider the combination effect of damping parameters, increase the anti-yaw damping appropriately, and reasonably reduce the lateral damping of the second system, which can provide theoretical basis for the selection and optimization of shock absorber parameters.

Dynamic Characteristics Analysis of Automotive Components with Composite Material Based on Smoothing Strategy

XU Fengxiang ZHANG Suo WU Kunying

2018, 46(9):  125-130,139.  doi:10.3969/j.issn.1000-565X.2018.09.017

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Composite materials used in automotive body lightweight design have been paid on more and more attention. In order to further improve the numerical accuracy for dynamic analysis of automotive structure made from composite materials, the paper presents a smoothing strategy to conduct laminated shell element which is used into dynamic characteristics analysis of composite structural components. By the proposed smoothing strategy, the shear locking is successfully alleviated using the discrete shear gap method and the system stiffness matrix is effectively tuned after employing the gradient smoothing technique aiming to avoid the “over-stiff” phenomenon. Both typical automotive components such as engine cover and door made from composite materials are performed in dynamic characteristics analysis, and the accuracy of the obtained results is compared with existing finite element commercial software. The results from both typical engineering examples show that the proposed smoothing strategy makes the computational results be higher accuracy.

Research on Mechanical Properties of Corrugated Steel Plate with Relieving Slab Based on Equivalent Stiffness#br#

LI Baijian FU Xinsha ZHU Liangsheng

2018, 46(9):  131-139.  doi:10.3969/j.issn.1000565X.2018.09.018

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To explore the mechanical properties of Corrugated Steel Plate with relieving slab, using a Corrugated Steel Plate as a numerical example, the numerical analysis model was established based on equivalent stiffness method and the model is proved reasonable. Furthermore, the mechanical properties of the Corrugated Steel Plate with relieving slab under vehicle loads are analyzed, and the conclusions were drawn: relieving slab can not effectively reduce the internal force of the Corrugated Steel Plate structure under dead load, maybe make the internal force of the structure higher; relieving slab can effectively reduce the bending moment of the structure under the vehicle loads, about 50% lower than which does not set a relieving slab, but the relieving slab has little effect on the axial force of the structure under the vehicle loads; the most unfavorable conditions is the maximum axial load act on the crown, which can produce the maximum bending moment and should be considered during design phase.

Single-echelon Initial Inventory Optimal Allocation for Civil Aircraft Spare Parts with Importance Degree

FENG Yunwen LU Cheng XUE Xiaofeng LI Yongkai

2018, 46(9):  140-148.  doi:10.3969/j.issn.1000565X.2018.09.019

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To investigate the influence of importance degree on inventory allocation of spare parts for civil aircraft, the single-echelon initial inventory optimal allocation model was established based on the theory of Boeing and Airbus models. And the decomposed-coordinated marginal analysis method was proposed combined with the marginal analysis method, to implement inventory optimal allocation for expendable, rotable and repairable parts. Firstly, the procedure of single-echelon initial inventory optimal allocation for spare parts was elaborated under considering importance degree. Secondly, the initial inventory optimal allocation model with the fleet availability as the optimal objective, the spare parts cost and the support probability as the constraints was constructed. Thirdly, the decomposed-coordinated marginal analysis method was applied to accomplish the solution of the single-echelon initial inventory optimal allocation model of spare parts. Lastly, the spare parts of civil aircraft door system as the study object, initial inventory optimal allocation of spare parts was finished. Through the analysis results, the initial inventory optimal allocation for each spare part, the cost 170684.61 dollars and the fleet availability 0.9999 are obtained in the condition of satisfying constraints. Through the comparison of traditional inventory optimal allocation of spare parts, the developed method with importance degree is validated to be feasible and effective.