Table of Content

25 June 2017, Volume 28 Issue 12

Previous Issue    Next Issue

Working Principle of New Expanding-ring Type Overrunning Clutchs and Their Self-locking and Overrunning Conditions

DU Li, PENG Siyang, WEI Dong, SONG Zeliang, WU Zhenhong

2017, 28(12):  1387-1393. 

Asbtract ( )   PDF (656KB) ( )  

References | Related Articles | Metrics

A new expanding-ring type overrunning clutch was proposed, its self-locking component was a ring which was in a lower pair face contact with the output members and whose carrying capacity was improved compared with conventional higher pair type overrunning clutchs. The self-locking and overrunning conditions were analyzed and the self-locking conditions on the pin roller wear sensitivity were studied. Theoretical study shows that the clutch performance is superior to the pin roller type overrunning clutchs. Finally, the simulation and experimental verification of a new type of tension ring clutch were carried out.

A New Method of Aviation Blade Measurement via Applications of Conoscopic Holography Principle

ZHOU Awei, SHAO Wei, WU Ying

2017, 28(12):  1394-1399. 

Asbtract ( )   PDF (604KB) ( )  

References | Related Articles | Metrics

Aiming at the characteristics of the complex shape and large curvature variation of the aviation blade profile, this paper proposed a new measurement method via application of conoscopic holographic principle. This method used the same beam conoscopic lighting, and allowed the variation ranges of the angles between normal direction of the surfaces to be measured and optical axis to be larger, so as to avoid the influences of blade curvature on the measurements. Then, the proposed data registration algorithm based on implicit polynomials which may match measurement data with CAD model data, may be used to obtain blade surface error distribution and the deviations of geometric parameters, and provide accurate parameters for the adjustment of processing parameters. Experimental results show that measuring repeatability of the method is less than 8μm, which meets the measurement requirements of aviation blades for the adaptive machining.

Hybrid Reliability Analysis for Flexible Manipulator Vibrations in Engineering Machinery

ZENG Guang, , JIANG Chao, NI Bingyu

2017, 28(12):  1400-1405,1412. 

Asbtract ( )   PDF (549KB) ( )  

References | Related Articles | Metrics

Based on the probabilistic and interval hybrid model and structural reliability analysis method, vibration reliability analyses for engineering mechanical systems with multi-joint flexible manipulators was investigated. According to different types of the uncertain parameters in mechanical manipulators, the uncertainties were quantified by random and interval variables. With simulation data of finite element model, a RBF agent model was built for structural natural frequencies with regard to mechanical manipulator’s parameters. And the failure probability of the mechanical manipulators due to resonance was evaluated based on the probabilistic and interval hybrid reliability analysis method. Finally the above analysis method was applied for a practical project example to make an illustration. 

Analysis of Influences of Contact Stiffness Variations on Advanced Support Dynamic Response in Moving Processes

XIE Miao, LIU Zhixiang, MAO Jun

2017, 28(12):  1406-1412. 

Asbtract ( )   PDF (871KB) ( )  

References | Related Articles | Metrics

The dynamic response characteristics of advanced support during the stepping processes were studied by numerical simulation and experiments. A coupling dynamic model of advanced support and roof was established with block rock theory. The stepping processes of advanced support were simulated with the contact stiffness changes between support and roof. The dynamic responses of the roof, the first and the second support groups were researched by changing the steps of advanced support and top contact stiffnesses, in the form of step mutation, exponential, linear and logarithmic. MATLAB was used to establish dynamic differential equation of advanced supports, and four order Runge-Kutta method was used to solve dynamics problems of advanced supports. The results of simulations and experiments show that abrupt vibrations of the roof and the support group may be caused by using the method of step mutation. The logarithmic, linear and exponential rigidity changing way were used to control stepping processes, that may reduce vibrations of the roof, the first and second support groups, and the effects of the three ways gradually increase.

Structure Optimization and Dynamics Analysis of 3-CUR Decoupled Parallel 3D Printers

ZENG Daxing, ZHANG Xing, FAN Mingzhou, LI Xiaofan, HOU Yulei

2017, 28(12):  1420-1426. 

Asbtract ( )   PDF (717KB) ( )  

References | Related Articles | Metrics

Taking a 3D printer of fused deposition modeling as the research object, the shortages of the present 3D printers were pointed out, the output motion characteristics were expounded and a decoupled parallel mechanism would be applied to the 3D printers. Selecting 3-CUR decoupled parallel mechanisms as the mechanical body of 3D printers and discussing its rationality, the mapping relations among inputs and outputs were given, the kinematic Jacobian matrix and the ranges of driving angles that supported continuous printing were obtained. Aimed at dexterity, the ranges of driving angles of the mechanism were optimized. Then aimed at the printing spaces, the genetic algorithm was introduced to get the optimal values of the mechanism parameters. By establishing the error model among inputs and outputs of the mechanism, analyzing the positioning accuracy of the mechanism and compensating the errors, the dynamics model of mechanism was established and verified based on Newton-Euler method, which provides theoretical basis for designs of the prototypes.

Research on Pulley Deflection Losses of Metal Belt CVT

FU Bing, ZHOU Yunshan, GAO Shuai, LI Quan, AN Ying

2017, 28(12):  1420-1426. 

Asbtract ( )   PDF (717KB) ( )  

References | Related Articles | Metrics

In order to reduce the transmission loss of CVT，the loss mechanism of pulley deflections was analyzed and a mathematical model of pulley deflection loss calculaton was derived． Based on the pulley deflection model which was established by using finite element method，the radial penetration loss and the wedge loss caused by pulley deflections were quantitatively analyzed，the influence laws of CVT speed ratios and input torques on pulley deflection losses were concluded．The results show pulley deflection losses increase with the increases of input torques，the pulley deflection losses in maximum speed ratio and minimum speed ratio are greater than that in middle speed ratio，the radial penetration loss is the main contributor to pulley deflection losses．The pulley deflection losses may be reduced by increasing pulley equivalent axial stiffnesses in maximum working radius．The calculation model was validated by the experimental data in test bench．

Partitioned Sliding Mode Adaptive Neural Network Control of Calm Movements of Dual-arm Space Robot after Capturing a Spacecraft

CHENG Jing, CHEN Li

2017, 28(12):  1427-1433,1441. 

Asbtract ( )   PDF (700KB) ( )  

References | Related Articles | Metrics

The calm control for attitude and joints disturbed motions and the coordinate operation problems were discussed. At first, according to the theorem of impulse and the closed-loop constraints, the impact effects of dual-arm space robot capturing a spacecraft were analyzed and the dynamics equations of composite closed chain system were obtained simultaneously. Then, in order to satisfy the compute capacities of spaceborne computer, a partitioned sliding mode adaptive control scheme was designed based on neural network. The dynamics of combined system was considered as a set of nonlinear interconnected subsystems. Concurrent neural networks were applied to approximate the unknown dynamics of the subsystems, the computational efficiency was improved by concurrent processes. The partitioned sliding mode adaptive controller was designed to eliminate both interconnection terms and approximation errors. The weighted minimum-norm theory was introduced to distribute torques guarantee that the cooperative operation between manipulators. At last, numerical examples demonstrated the effectiveness of the proposed control scheme.

Load Analysis of Neutron Spectrometer Sample Table Rotary Bearing

LI Yang, WU Yunxin, GONG Hai, ZHANG Yu,

2017, 28(12):  1434-1441. 

Asbtract ( )   PDF (724KB) ( )  

References | Related Articles | Metrics

According to the three-row roller slewing bearing structure characteristics and load characteristics, the establishment and solution of the mechanics analysis model were achieved by using Hertz contact theory. The contact characteristics of slewing bearing between the roller and the raceway were analyzed by using FEM on the basis of mechanics analysis model, then the effects of axial loads, radial loads and roller numbers on the slewing bearing stiffnesses were analyzed. The results show that under the extreme conditions the equivalent stress of contact area of upside roller and raceway is largest, which is as 76.98MPa, the maximum equivalent stress of outer ring raceway is as 14.82MPa, the maximum equivalent stress of inner ring raceway is as 11.26 MPa. Stiffnesses increase with increasing of axial loads, radial loads and roller numbers respectively and the relationship among them are nonlinear, when the axial loads increase to 1200kN and radial loads increase to 300kN, axial stiffness and radial stiffness increasing rates slow down significantly, when the roller numbers increase to 170, the axial stiffness increasing rates speed up significantly. The study may provide useful references for neutron spectrometer sample table rotating motion mechanism structure design.

Numerical Analyses on Fatigue Life for Compressor Blades under Complex Loads

ZHANG Junhong, LIU Meng, FU Xi, KOU Haijun, LIN Jiansheng

2017, 28(12):  1442-1448,1467. 

Asbtract ( )  

References | Related Articles | Metrics

In order to improve service life of blades, three blade models were built based on reverse engineering to calculate stress distribution and fatigue life of blades under complex loadings. Considering the influence of centrifugal loads and aerodynamic loads, stress distributions of compressor blades were solved under complex loads. Moreover, the fatigue limit and life prediction model parameters were defined through the fatigue tests, and the fatigue life of compressor blades under the typical working conditions were predicted by nonlinear continuous damage model. Comparing the differences of stress values and fatigue life among three models, results show that the restoration degree of blade geometrical features for the calculation model must be considered when numerical calculations were carried out for blades with complex torsional characteristics.

Research on Resistance Type Support Rods of Vertical Axis Wind Wheels

ZHANG Lijun, ZHAO Xinhui, MA Dongchen, MI Yuxia, WANG Hanxiang, LIU Yanxin

2017, 28(12):  1449-1455. 

Asbtract ( )   PDF (657KB) ( )  

References | Related Articles | Metrics

In order to study the influences of resistance type support rods on the self-starting capabilities and wind energy utilizations of vertical axis wind wheels, the aerodynamic characteristics of resistance type support rods were analyzed and the relative velocity distributions in downwind and upwind zones were obtained. Then the average output torques of the circular cross-sections, V-shaped convex cross-sections and V-shaped concave circular cross-sections were compared theoretically respectively , which shows that the vertical axis wind wheels that use the resistance type support rods with the V-shaped concave circular cross-sections have the self-starting capabilities and high wind energy utilizations. In order to further verify the above results, the average output torques of the circular cross-sections, V-shaped convex cross-sections and V-shaped concave circular cross-sections in the different speeds were calculated by the numerical simulation method respectively. The simulation results show that the supporting rods which use the V-shaped concave circular sections may improve the self-starting capabilities of vertical axis wind wheels compared with the traditional circular cross-sections, and the wind energy utilizations are increased by 3.44%, which are consistent with the theoretical analysis results.

Research on Rationality of Multi Domain Requirements for Products Based on DSM

YANG Qin, SONG Fei, PAN Gaofeng, JIAO Haisen

2017, 28(12):  1455-1461. 

Asbtract ( )   PDF (573KB) ( )  

References | Related Articles | Metrics

Facing to the conflict problems of customer requirement nodes due to constraints and node sequences, an expression method of customer requirements was proposed based on DSM. This method was composed of five steps: building customer requirement templates, building constraint rules, optimizing the DSM of customer requirements expression processes, checking the constraint rules, calculating the rationality of customer requirements. The multi domain collaboration of product requirements was realized and quantitative basis for judging the rationality of requirement node sequences and requirement expressions was provided. Finally, the practicality of the method was illustrated by automatic guided vehicle(AGV).

Breakout Prediction for Continuous Casting Based on SA-PSO to Optimize Parameters of SVM

FANG Yiming, ZHENG Hejun, LIU Le, HU Chunyang

2017, 28(12):  1462-1467. 

Asbtract ( )   PDF (519KB) ( )  

References | Related Articles | Metrics

In order to overcome the problems that the neural network model was difficult to obtain a high accurate breakout prediction for continuous casting under the conditions of small sample training data, a breakout prediction for continuous casting was proposed based on SA-PSO algorithm to optimize the parameters of SVM. Firstly, the PSO algorithm was introduced into the training processes of SVM, increasing the optimization speeds of breakout prediction model by using the advantages of less parameters and fast optimization speeds. Secondly, SA algorithm was used to evaluate the new positions of updated particles, and to determine whether the new positions were accepted, which could avoid the PSO algorithm steped into the local extremum in optimization processes. Finally, the breakout prediction for continuous casting was tested by the history data of continuous casting. The results show that the proposed algorithm may make the breakout prediction accuracy reach 98.8%.

Study on Key Technologies of Hybrid Controllers for Mobile Robots

XU Peipei, WANG Guoqing, ZHAI Jiaxing, LI Zhaolu, ZHANG Zhixin

2017, 28(12):  1468-1473. 

Asbtract ( )   PDF (659KB) ( )  

References | Related Articles | Metrics

Aiming at the high cost ，poor real-time capability and other issues of mobile robot controllers for implementing many functions ,such as the motion control, network communication, multimedia UI interaction ,the device remote monitored control and so on, a hybrid controller scheme was put forward herein that multi-core heterogeneous microcontroller combined with Android mobile devices and finished a prototype system. The system adopted the management-oriented multi-microcontroller motion control systems and signal acquisition systems which connected with Android mobile devices through the OTG. Android mobile devices implemented multimedia UI interaction, WiFi and WiFi Direct communication, image transmission and the monitor data of device state transmission and processing. The server implemented storages and applications of device state data. The prototype system was verified to be fine, and reached the goals of design by tests.

Analysis of Inclusion Relation of Parameterized Models for Product Platforms

ZENG Shasha, PENG Weiping, YAN Wei

2017, 28(12):  1474-1483. 

Asbtract ( )   PDF (777KB) ( )  

References | Related Articles | Metrics

Based on Apriori algorithm, inclusion relations of parameterized models and their concealing database were studied. A method which might avoid the two performance bottlenecks of Apriori algorithm was used. This method may reduce the times of scanning database. The results of inclusion relations were output by comparing the confidence of frequent itemsets. Taking the data of high pressure valves as the target, the theory of inclusion relation was confirmed by the Explorer module of Weka and the inclusion relations of high pressure valves were output.

Early Weak Fault Diagnosis of Gearboxes Based on Energy Aggregation and EWT

WANG Youren, CHEN Wei, SUN Canfei, SUN Quan, HUANG Haian

2017, 28(12):  1484-1490. 

Asbtract ( )   PDF (730KB) ( )  

References | Related Articles | Metrics

For the early faults of gearboxes, the fault features were not obvious, and the vibration signals were nonlinear and non-stationary, a method was proposed based on energy aggregation and EWT (EA-EWT). Vibration signals were decomposed by EA-EWT, and the maximum kurtosis envelope spectrum entropy criterion was used to filter the sensitive signals. For the selected signals, the minimum entropy deconvolution was used to reduce the noise. The Hilbert envelope spectrum of the signals was analyzed after noise reduction, and the fault types were identified by the frequency components in the envelope spectrum to realize the early fault diagnosis. The experimental results show that the new method may significantly enhance the early weak fault characteristics and improve the early fault diagnosis performances.

Research on Bulging Technology of AA6061 Aluminum Alloy Tubes with Square Cross Sections

BI Jiang, , ZHAO Changcai, DU Bing, CHEN Xiaohua, DONG Guojiang

2017, 28(12):  1491-1498. 

Asbtract ( )   PDF (829KB) ( )  

References | Related Articles | Metrics

The AA6061 aluminum alloy extruded tube might not be formed into complex parts for its high strength and poor plasticity at room temperature. This paper put forward a new technological process: including solution treatment+solid granule medium bulging+aging treatment. During the processes, the mechanics properties of the tested alloy could be changed by heat treatments to satisfy the process requirements and the processing method of high strength aluminum alloy also could be realized by solid granule medium bulging technology. The AA6061 extruded tubes were investigated to show the effects of solution treatments on mechanics properties. At a solution temperature of 560℃ and time of 120min, the elongations of AA6061 aluminum alloy tubes increase by 300%, the strength and the hardness decrease dramatically too. Therefore, the AA6061 aluminum alloy tubes meet the requirements of bulging by the improvements of formability. The experiments show that the strengths and hardnesses of AA6061 aluminum alloy workpieces recover to the as-received alloy at an aging temperature of 180℃ and time of 360min. The typical tubes with square cross sections were trial-produced in lab by using the present forming method. The forming tests show that, the percentage elongation of AA6061 aluminum alloy tubes in ring direction may reach 34%.

Hot Stamping Forming Processes and Experiments of 22MnB5 Ultra-high Strength Steels

XUE Kemin, SUN Dazhi, LI Ping, GONG Zitianzong

2017, 28(12):  1498-1503,1511. 

Asbtract ( )   PDF (807KB) ( )  

References | Related Articles | Metrics

Considering the thermal physical property parameters and mechanics performance as the functions of temperature, a thermo-mechanics coupling FEA model of hot stamping processes with 22MnB5 ultra-high strength steel was established using ABAQUS software, and the stress and strain distributions of the blanks during hot stamping forming processes were obtained by the numerical analyses with the appropriate hot stamping processing parameters. The effects of different initial temperatures on the thickness distributions, springbacks and cooling rates of the parts were studied. The hot stamping experiments of 22MnB5 ultra-high strength steel were carried out with initial temperature of 900℃, thickness distributions and springbacks of hot stamping parts show better fitness with the numerical simulation, and the quenched microstructure of each regions is typical acicular martensite. Besides, due to the cooling rate at the bottom of the part is much larger, the martensite microstructure is more uniform and fine.

Micro-mechanism of Galvanic Corrosion Behavior and Its Effects on Materials' Performance

SHI Ping'an, LIU Daoxin, WAN Qiang

2017, 28(12):  1504-1511. 

Asbtract ( )   PDF (969KB) ( )  

References | Related Articles | Metrics

In order to study the effects of the stress and galvanic factors on the corrosion behavior of 2A12 alloy and 45 steel, a special loading device were applied to investigate the galvanic corrosion between 2A12 alloy and 45 steel under applied tensile stress in neutral 3.5% NaCl solution. The morphology changes on the surface of 2A12 alloy was investigated based on electron microscopy (SEM) and X-ray diffraction (XRD), and the effects of galvanic corrosion on the mechanical properties of 2A12 alloy were investigated using the methods of tensile test. The results show that the morphology of corrosion possess characteristics of uniform pitting corrosion macroscopically however that of localize corrosion microscopically without the effects of external stresses. The pitting corrosion develops into larger dimension and the localized corrosion penetrated into the matrix with the external stress increased. The microcosmic structure and corrosion morphology of 2A12 alloy are changed from the external stress, which may evidently accelerate the galvanic corrosion of anode materials 2A12, especially localized corrosion expanded from the surface into the entrails. Based on the characteristics of corrosion metrics and the weight loss ratio of 2A12 in different external stresses and corrosion time, the forecasting model was established to predict the performance and life.