Table of Content

25 December 2015, Volume 26 Issue 24

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Fatigue Life Prediction Method Based on Non-equidistant  Grey  Model

Li Guoyong, Gu Zhengqi, Zhang Sha, Ma Xiaokui, Li Jiping, Hu Kai

2015, 26(24):  3267-3274. 

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Combining the non-equidistant grey model with traditional Miner rule, a method was proposed to predict the fatigue life of structural components. Firstly, in the case of non-equidistant stress grading statistics, non-equidistant grey model was constructed, and genetic algorithm was used to optimize the values of background value to ensure the accuracy. And, combining the non-equidistant grey model with Miner rule, grey Miner method was constructed to predict fatigue life. Then a numerical example proved the accuracy of non-equidistant grey model and the effectiveness of grey Miner method. Finally the method previously mentioned was applied to the fatigue life prediction of A-shape frame.The results show  that it improves the accuracy of fatigue life prediction of A-shape frame and proves the effectiveness of the grey Miner method to predict fatigue life of components.

Solution and Validation of  Non-linear  Electromechanical-coupled  Dynamics  for  Piezoelectric Actuator

Li Chong, Xu Lizhong, Xing Jichun

2015, 26(24):  3275-3281. 

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On the basis of  non-linear  piezoelectric effect  and  non-linear  displacement effect,the  non-linear electromechanical-coupled  dynamic equations of piezoelectric actuator  were  established.Applying  Linz  Ted-Poincaré method,response  equations of weak nonlinear free vibration, force vibration near to natural   frequency,subharmonic vibration  were deduced.And the comparison between non-linear   response and linear response was investigated. Using the fourth order Runge-Kutta and experimental method, the theoretical derivation was  verified.Results show,in the two types of non-linear effects, the impact of piezoelectric non-linear effect on actuator is primary. Numerical results agree well with analytical solutions, and testing frequencies are close to non-linear resonance frequencies.

Type Synthesis of Fully-decoupled 3T1R Parallel Mechanism Based on Screw Theory

Chen Hai, Qin Youlei, Cao Yi,

2015, 26(24):  3282-3288. 

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Based on the screw theory and the driven-chain principle, a method of structural synthesis for fully-decoupled three-translational and one-rotational (3T1R) parallel mechanisms was proposed. Firstly, according to the desired characteristics of the parallel mechanism (moving along X, Y, Z axis and rotating about Z axis, respectively) and requirements,the direct  and the inverse Jacobian matrices had to be diagonal, the desired forms for the direct and the inverse Jacobian matrices were constructed. Secondly, according to the features of the direct and the inverse Jacobian matrices, the effective screws, the actuated screws and the mobile un-actuated screws of each leg were established based on the reciprocal screw theory and the structural synthesis of each kinematic chain for fully-decoupled 3T1R parallel robotic manipulators was performed in the light of different connectivity of the limbs. Finally, the parallel mechanism was obtained by the connection of 4 chains with the moving platform and the fixed base in terms of the parallel mechanism kinematic principles. The output of the synthesized parallel mechanism was provided by the independent input-driven of each chain and the direct Jacobian matrices maintained diagonal  during the moving process. The parallel mechanism is fully-decoupled,which can be controlled with ease and has a certain application prospect.

Size Effects and Layout Optimization of Assembling Module for Periodical Thin-and-long Structures

Sun Shiping, Liu Yufeng

2015, 26(24):  3289-3294. 

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A repetitive module assembling method and a mixed finite element model   were presented where  the computational difficulties, intermediate density and complex geometries existed.The influences of repetitive module number,material volume fraction and beam section sizes on optimization results were   comparatively investigated on the basis of optimization design of  thin-and-long cantilever structure  subjecting to uniform pressures.The results show that optimization configuration with regularity,simplicity and easy to manufacture can be obtained by repetitive module assembling method.Size  effects of periodic thin-and-long structure are  obvious, and  there is an optimal module size for periodic  thin-and-long  structure to maximize stiffness.Regular truss-like configuration of repetitive module is obtained with  concurrent optimization of both module size and layout,based on mixed finite element model. Finally, topology optimization of a thin-and-long trapezoidal cantilever structure was achieved using the proposed method.

Parallel  Joint  Surface  Error  Modeling  Based  on  Assembly Positioning Priority

Lü Cheng, Liu Zijian

2015, 26(24):  3295-3301. 

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The formation mechanism and calculation method of assembly error of parallel joint surface under the effects of assembly positioning  priority  were analyzed.In view of  the common plane joint surface and cylindrical joint surface,the formation of joint surface error and the invalid reason of assembly precision were analyzed,the variations  of errors  were  described  by SDT method.In view of the interplay of position change between parallel joint surfaces, the concept of assembly positioning priority was defined,and the judgment criterions of the assembly positioning priority of parallel joint  surface were analyzed in details.The specific composition and calculation methods of the errors of all parallel joint surfaces were determined based on the assembly positioning priority.The common forms of parallel joint  surface were listed,and  one  of  them was  taken  as an example for assembly error analysis.As a result, the practicability of this method was verified,and the references of assembly error analyses,part precision design,assembly success rate  calculation and so on were provided.

Research on Position  and  Gesture of Cleaner of  Monorail Tracked Robot  for Clean of Solar PanelShen

Chengwei, Hang Lubin, Bian Huaiqiang, Wang Jun Lu Jiuru, Wang Yuzhao, Qin Wei, Huangfu

2015, 26(24):  3301-3306. 

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Based on bogie technology of monorail vehicle,a monorail tracked robot for clean of solar panel was presented.According to mechanical and geometrical properties of  the cleaning robot and motion mechanism of the bogie, five hypotheses were proposed and the robot-panel system model was built based on the spring-damper unit.The motion equations of cleaning robot during travel were established and  the dynamic  responses of bogie under the input of cleaner 's motion were solved. Then the corresponding position and gesture of cleaner within motion range were determined. By defining working function of cleaner based on the piecewise, the simulation model was built and curves of position and gesture  were plotted in  MATLAB/Simulink.The results show that the position of bogie is affected by the motion of cleaner.The position and gesture of cleaner  are related to its working positions.Further prototype test verifies the rationality of structural design and analysis model.

An Improved Genetic  Algorithm and Its Applications  in Clutch Parameter Optimization

Xu Liyou, Li Qing, Zhou Zhili

2015, 26(24):  3307-3311,3317. 

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For the clutch plate parameter optimization process of multi-objective, multi-parameter and multi-constraint features, an improved genetic algorithm was put forward.Based on  AHP,the part objective function weight coefficients  were allocated initially,combination coefficients among  parameters and sensitivity coefficients  were introduced in this algorithm,combination coefficients  were used in crossover and mutation, sensitivity coefficients were  used in the dynamic adjustment of weight coefficients.Taking Dongfanghong-LA3004 tractor shifting clutch for the optimization example, based on the traditional genetic algorithm and the proposed improved genetic algorithm respectively, the clutch parameters were optimized, and the optimization results were compared with the original plan, the result analyses  show that the proposed improved genetic algorithm can get the global optimal solution, at the same time, improves the efficiency of optimization.

Effects of Key Parameters  of  Diesel  Late   Intake  Valve  System  on  Intake Performance

Pan Suozhu, Peng Yizeng, Han Weiqiang, Han Zhiqiang, Tian Wei, Yin Long

2015, 26(24):  3312-3317. 

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A numerical model of  DK4A diesel engine was established on the basis of its  electric hydraulic  mechanism.The effects of intake valve closing angle on the intake flow rate of the diesel engine  were  analyzed under a certain maximum lift limit.The effects  of the additional lift limit and intake valve closing angle on the intake state parameter were  studied. Results indicate that the maximum additional lift limit has a  little effects  on the intake flow rate,and  the change rate of intake flow rate is less than 3％ in the same late closing angle, and the intake flow reduces  with the late closing angle  increasing.The  increase of late closing angle is benefit for reducing the  pressure and temperature at the end of compression.The ignition  delay period becomes larger when the late closing angle increases, but the maximum additional lift limit has little effects on TDC temperature and pressure.The  change rates  of  TDC pressure and temperature  are  less than 5％ in the same closing angle.

Design Theory of Motion Integration Mechanism with Roller  Movable Tooth

Liu Dawei, Ren Tingzhi, Jin Xin, Ma Qiang

2015, 26(24):  3318-3322,3335. 

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A concept of motion integration was presented to improve the efficiency and  to  reduce the space of series mechanisms Combining with  movable tooth gear and noncircular gear theory, the motion integration   mechanism  with  roller movable tooth was proposed. Firstly, a eccentric circle was selected as the wave generator.A tooth profile model of the inner ring was built under any transmission ratio, with continuous transmission conditions discussed. Then a mathematical relationship in the maximal number of movable teeth, the number of period of transmission ratio and the number of inner ring teeth were  studied. When the number of movable teeth was less than two, a parallel movable tooth gear was constructed to realize any speed ratio. Finally, the design process of a motion integration mechanism with roller movable tooth was given to achieve the transmission ratio of series noncircular gear system, which laid  the foundation for applying the new gear,and  guided the research of other movable tooth gears.

Design and Analyses of a New Firing Platform for Shooting Tests

Jin Xin, Zhou Kedong, He Lei, Huang Xueying, Zhang Junbin

2015, 26(24):  3323-3326. 

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A new firing platform for small arms shooting tests  was designed herein, in order to exclude the differences of shooting results caused by different shooters during shooting tests.The structure of firing platform was designed based on national standard and characteristics of human-weapon system,and the parameters of spring-damping systems were obtained by contrastive analysis of model simulation and human tests. Experimental  results show that the shooting results of designed firing platform are similar to human shooter results.Therefore,the  designed firing platform
in shooting tests  may  exclude the differences  of shooting results caused by different  shooters, so the evaluation of test results by designed firing platform is  more scientific.

Fault  Pattern Identification of  Hydraulic Pump  Based  on  VPMCD  and  LPP Algorithm

Wang Yukui, Li Hongru, Xu Baohua

2015, 26(24):  3327-3335. 

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Aiming at the problems that vibration signals were complex and the effective features  were  difficult to extract,a  novel fault feature extraction method for pump was proposed based on LPP   algorithm.The vibration signals of pump were  decomposed into a number of intrinsic mode function(IMF) with ensemble empirical mode decomposition(EEMD),and  then sensitive IMFs  which contained more state informations were selected,and the high dimensional  fault  feature  sets were extracted from the sensitive IMFs.Then the sensitive feature sets were gained by carrying out fusion and dimensional reduction to the high dimensional  feature sets  with LPP processing.On account of the favorable performance of  VPMCD,the VPMCD was proposed to realize the fault pattern identification of pump.A variable predictive model(VPM) of each sensitive feature was established and the fault pattern of pump was diagnosed based on the VPMs.The analysis results of practical pump signals  testify the rationality and availability of proposed method.In addition,comparative analysis results demonstrate the more favorable performance of proposed method.

3D  Simulation of Temperature Field during Welding of Stainless Steels  with  Meshless  Symmetric  Particle   Method

Xiao Yihua, Zhang Haofeng, Ping Xuecheng, Li Qinghua

2015, 26(24):  3336-3340. 

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A MSPM was introduced for the simulation of temperature field during welding, and its program was developed. A 3D numerical model for the tungsten inert gas(TIG) welding of stainless steel was established.The model was solved with the proposed method, and the temperature distributions as well as the shape and size of welding pool were obtained.Simulation  results were compared with the corresponding results by experiments and finite  element method(FEM).It is found that the presented method achieves the same order of accuracy but better efficiency compared with FEM.A model with gradual change of particle spacing was also developed. The computational efficiency is improved with the model. By this model, influences of Gaussian heat source and double ellipsoidal heat source on the welding simulation results were studied. Numerical results show that the latter leads to better agreements between the simulation and experiment in the shape of welding pool.

Numerical Simulation of Cavitation Flow in Piston Pump Based on Full Cavitation Model

Liu Chunjie, Wu Xiaofeng, Gan Weimin, He Yafeng

2015, 26(24):  3341-3347. 

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According to the cavitation phenomenon in a typical swash plate axial piston pump, the continuity equation, motion equation and vapor-liquid mixed mass transport equations in a high pressure piston pump were built by consideration of the influences of the medium compressibility and turbulence model. And the numerical simulation of vapor-liquid flow in the pump was carried out. The simulation results show that the cavity in piston pump is affected by different speeds, pressure differential, and valve plate structure. Finally, compared with the experimental data, the simulation results are agreement with the actual data.

Research on Integrated Process Planning and Scheduling Problem with Consideration of Uncertain Processing Time

Ba Li, Li Yan, Yang Mingshun, Liu Yong, Gao Xinqin

2015, 26(24):  3348-3355. 

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In order to make IPPS problem more accordant  with the actual conditions,uncertain processing time was considered into IPPS problem. Processing time was expressed by TFN.An IPPS problem with consideration of fuzzy processing time was proposed. The maximum fuzzy makespan was  as the  main target which will be minimized. The model was built for the problem and a genetic algorithm(GA) with a multi-layer encoding structure  was  proposed to solve the problem. Finally, the model and algorithm were proved by  an application cases.

Monitoring  Wear  Debris  in Oil Utilizing RFID Signal  Transmission  Features

Yin Aijun, Ren Hongji

2015, 26(24):  3356-3359. 

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A preliminary study on a low-cost solution for monitoring ferromagnetism debris in oil  was demonstrated based on electromagnetic wave transmission features.A model  was set up to simulate the affection of  debris parameters on electromagnetic wave transmission features.Simulation results indicate  an abvious  relevance between debris density and  electromagnetic wave energy distribution.An experiment was conducted to verify the   simulation results based on RFID.

Research on Magneto-rheological Fluid Self-generating Electricity Transmission of Temperature-controlled by SMA

Qiao Zhen, Huang Jin

2015, 26(24):  3360-3365. 

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The working principles  of magneto-rheological fluid self-generating electricity transmission of temperature-controlled by SMA  were analyzed.The relationship of output displacement of the SMA temperature detect switch with temperature was established based on characteristics of temperature and mechanics of SMA.The relationship of output speed and output current with temperature was established based on output characteristics of generator and mechanics  characteristics of SMA  spring,and the relationship of magnetic induction  intensity and temperature-controlled switch resistance with the parameters of the generator was established according to the principles  of self-generating electricity . The relationship of output torque with temperature was established based on the viscosity and temperature equation.The results  indicate that the output displacement of spring, output current,output torque and  output speed can change rapidly with the temperature. According to expression of loss power,the  consumption energy of self-generating electricity transmission device is less than ordinary magneto-rheological fluid fan clutch under ordinary temperature range.

Study on Locking Time for Compound Sensitive Seat Belt

Zhao Xiaoyu, Wang Xiaocong, WangYansong, Wang Jianong

2015, 26(24):  3365-3369. 

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This paper  presented a  locking structure of compound sensitive retractor,which was in accordance with the Standard GB14166-2013 “safety-belts,restraint systems,child restraint systems and ISOFIX child restraint systems for occupants of power-driven vehicles”. The retractor 's structural composition and operation principles were analyzed. The equations of motion for the body reactor, belt reactor, and inclined locking mechanism were established. An analytical model for locking time was obtained. A simulation of safty belt locking time was analyzed by ADAMS. The simulation results are in agreement with the analytical solutions. 

Research  on  Pneumatic-hydraulic  Impactor  Based  on  Work  Status  Parameters

Liu Zhong, Zou Yu, Zhang Kai, Huo Yuanming

2015, 26(24):  3370-3374. 

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On the basis of the work principles of  pneumatic-hydraulic impactor,the paper constructed the mathematical model of the impactor and rock mechanics properties during the process of impact drilling,the co-simulation was carried out  based on MATLAB and AMESim, the work status parameter  curve of impactor was obtained under  the conditions of different feedback pressures  of nitrogen chamber, different work flows  and different rock properties.The simulation results  suggest that,adjusting feedback pressure of nitrogen chamber and work  flow can realize the regulation of impact energy continuously,measurement of piston rebound speed of the impact system can realize the identification of drilling status of the iimpactor.

Feasibility Analyses of Improving Magnetic Memory Testing Sensibility by Strengthening Magnetic Excitation Field

Zhang Weimin, Qiu Zhongchao, Yu Xia, Sun Hongbo

2015, 26(24):  3375-3378. 

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As one kind of magnetic detecting methods excited by weak magnetic field, the metal magnetic memory testing method was susceptible to be influenced by magnetic interference, thus it was low in sensitivity and reliability, and was difficult to be applied in the practical engineering. An improving magnetic memory detection sensitivity and reliability method was put forward by strengthening the magnetic excitation field. Through analyzing principles of the method, it is concluded that the method can effectively suppress the interference field and improve the detection sensitivity.

Solid Granule Medium Forming for Deep Parabolic-shape Thin Walled Parts

Zhao Changcai, Jia Xiangdong, Yang Shengfu, Qiu Gaosong

2015, 26(24):  3379-3385. 

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The forming process of large complex thin-walled parabolic-shape shell was the compound of drawing and bulging, which easily led to wrinkling and cracking. Solid granule medium forming used for sheet metal drawing was a new flexible die forming technology, solid granule microsphere was used to replace the rigid punch or female die(or elastomer, liquid). The sheet metal was formed under the internal pressure, which might avoid the side wall wrinkling in parabolic-shape workpiece deep drawing processes. Also, the uneven inner pressure distribution of solid granule medium could control the cracking in parabolic-shape workpiece drawing processes. Thus the forming limit of sheet was improved. According to the characteristics of the solid granules medium forming technology, a technological process of complicated thin-walled parabolic-shape parts was formulated, and a numerical model was established, and the forming process and technology parameters were analyzed through both numerical simulations and experiments. The results indicate that the solid granule medium forming is a simple process, the formed part has uniform thickness distribution and high quality, the springback value is small.

Study on the Initiation and  Propagation of Fretting Fatigue Crack on the Ti-6Al-4V Alloy Dovetail Joint

Yu Shurong, Wang Jielu, Li Shuxin, Song Wei

2015, 26(24):  3386-3390. 

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Fretting fatigue tests were conducted on the Ti-6Al-4V  Ti  alloy  dovetail joint  to investigate fretting cracks and  wear under various load levels.The results indicate that the fatigue life is significantly reduced due to fretting of the dovetail joint.The fatigue loading has more influence on crack propagation than on crack initiation.The  fretting cracks originate at the edge of the contact surface and orientate at 45°and stayed for 60~150μm,then propagate nearly perpendicular to the surface until fracture.The fracture surface shows that multiple cracking at contact surface but only one main crack dominated.

A New  Test  Method  of  Curve  Negotiation of  Railway  Vehicle  on  Roller Rig

Wang Qunsheng, Zeng Jing, Zhang Chuanying, Wei Lai

2015, 26(24):  3391-3395. 

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A  formula was deduced to calculate the creepage between wheel and rail at curve negotiation. The nonlinear vehicle system dynamics model  was  established,which could simulate the curve negotiating property on roller rig.A new test method to simulate the curve negotiate was introduced and the influences of different test methods on wheel-rail vertical force were studied. Analysis results  show  that during the time of railway vehicle on roller rig from unstable to stable，the test method which is in operation nowadays  may  cause great detriment to both of  the vehicle and the roller rig,while the new method can refrain it. Comparing the results calculated by two test methods with the  model of
curve  negotiation,all  of  the methods  have the same laws with the increase of the vehicle speed. In the comparison of the safety index based on two test methods，the difference between the results calculated by the new method and the model of curve negotiation   is smaller .It indicates that the new test method herein is  feasible.

Comprehensive Control for Multi-axle Vehicle Electronically Controlled Hydraulic Steering Systems

Liu Jun, Xie Yi, Lin Beiqing

2015, 26(24):  3396-3401,3407. 

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The multi-axle vehicle dynamics model was established based on the valve-control cylinder of 4 axis (8×2) heavy duty truck. Threshold control and PID online setting based on RBF(radial basis function) neural network control algorithm were used to optimize steering stability and steering wheel-wear. After simulating the dynamics model in MATLAB/Simulink, the time domain response of yaw velocity, centroid side-slip angle and lateral acceleration to the first axle angle step under the conditions of 20km/h and 50km/h were obtained and converted into bode diagram with frequency domain analyses. At the same time, under the conditions of running steering and parking steering, 3 kinds of corresponding step time domain response of the third axle angle with the open loop control, PID control and RBF neural network setting PID control were compared. The simulation results show that the vehicle has better operation stability and tire abrasion resistance. 

Differential Braking-based Anti-Rollover Control for Heavy-duty Vehicle

Xie Zhaofu, Zhao Liang, Guo Konghui, Zhang Qiang

2015, 26(24):  3402-3407. 

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Based on multi-body dynamics and considering the K&C characteristics of suspension,a 26-DOF nonlinear dynamics model of triaxial  vehicle with dual rear tire was established  using D 'Alember  inertia force theory,which had the properties of object-oriented.The optimal control torque  of   the deviation between actual motion state and ideal state of movement was calculated.Meanwhile, the differential braking coordinator,ABS controller and actuator of differential braking control system  were  designed.The step test  model was established to simulate the working conditions  of emergency avoidance and  the results show that the control system scheme is feasible and can  prevent the car rolled over effectively.