Table of Content

25 May 2016, Volume 27 Issue 10

Previous Issue    Next Issue

Experimental Research on HVOF Sprayed WC-17Co Coating at High Speed Grinding Mechanism

Guo Li, Jiang Zhishun, Shang Zhentao

2016, 27(10):  1279-1286. 

Asbtract ( )   PDF (746KB) ( )  

References | Related Articles | Metrics

By studying the effects of diamond grinding wheels and grinding process parameters on grinding force, grinding temperature, residual stress, surface microscopic morphology and surface roughness, the relationship between the maximum undeformed chip thickness and the specific grinding energy was researched and grinding removal mechanism of the HVOF sprayed WC-17Co coating was revealed under the conditions of high speed grinding. The influences of grinding temperature on residual stress in the WC-17Co coating workpiece were analyzed. The normal grinding force was discussed on the effects of the subsurface damage in the WC-17Co coating workpiece. The research results show that grinding removal mode of the HVOF sprayed WC-17Co coating is both of ductile and brittle. When the grinding wheel velocity is increased, the grinding forces decrease quickly before rising slowly，and the grinding temperatures are continued to rise, and the residual stress state changes from compressive stress to tensile stress, and the coating removal mode transforms from brittle fracture to ductile removal by degrees, the plastic deformation of the coating caused by high grinding temperature is the main cause of the transition of residual stress state. With the normal grinding force increases, average depth of subsurface damage layer of the coating becomes bigger. Increasing grinding wheel speed, reducing workspeed and depth of cut, the proportion of plastic removal of the coating may increase.

Design and Simulation of a Single Amplification Electromechanical Integrated Harmonic Piezoelectric Motor

Gao Lichao, Xu Lizhong, Li Chong

2016, 27(10):  1287-1293. 

Asbtract ( )   PDF (704KB) ( )  

References | Related Articles | Metrics

A single amplification electromechanical integrated harmonic piezoelectric motor was designed, and the working principles were illustrated. Besides, the design procedure, continuous transmission conditions and principles of parameter selection were given. For the failure regions existed in the motor, the maximum stress equation was deduced and was verified by comparing with FEM results. In addition, the natural frequencies, modal shape and displacement and stress response under excitation were analyzed. Results show, the maximum stress is as 45.54MPa, and the difference is only 4.04% comparing with FEM results. Under the action of incentive, the vibration displacement of movable tooth is largest, and stress concentration on tooth carrier is most serious.

Study on Contact Stiffness and Natural Frequency in Cylindrical Plunge Grinding

Chi Yulun, Li Haolin

2016, 27(10):  1294-1298,1326. 

Asbtract ( )   PDF (590KB) ( )  

References | Related Articles | Metrics

Based on the cylindrical plunge grinding system simplified dynamics model, a new method was provided to determine the contact stiffness accurately by using the time constant of material removal model. And, a dynamics model was established to analyze the relationship between the contact stiffness and the system natural frequency. At last, the changing rules of contact stiffness, system natural frequency (or chatter frequency) with different parameters were verified by experiments. The research results provide important experimental data and theoretic method for avoiding or controlling grinding chatters and optimizing the grinding parameters in future.

Dynamic Analyses for Two-way Pneumatic Fast Swiching Valve

Wang Chenggang, He Fan, Liu Jun, Yan Fureng

2016, 27(10):  1299-1303. 

Asbtract ( )   PDF (576KB) ( )  

References | Related Articles | Metrics

A dynamic simulation for opening and closing processes of a high-speed switch valve was set up herein. At the same time, using AMESim simulation pneumatic buffer device to simulate the optimal installation location, a two-way pneumatic high-speed switch valve was designed with the power of self-developed two-way impact cylinder. Analysis results show that, under the air pressure 0.7MPa, the two-way moving high-speed switch valve's opening and closing times are in consistent, they are all 0.038 seconds. If the valve plate impacts valve seat too fast, the components will be damaged. The distance between the pneumatic cushioning device and the front end of the piston rod should be as 20.5mm,both devices are connected by the power conversion device. It is worth mentioned that the speed of valve shaft too fast during the process of switch opening and closing can cause axial displacement. The results provide a reference for design of vertical plate type butterfly valve used in flammable and explosive medium.

Study on Dynamic Characteristics of Unsteady Pneumatic Weight Drop Seismic Source

Jiang Faguang, Liu Xiaoning, Li Jinfu, Liang Zheng,

2016, 27(10):  1303-1307. 

Asbtract ( )   PDF (569KB) ( )  

References | Related Articles | Metrics

Based on the theory of gas dynamics and the discretization of continuous attributes, a dynamic numerical model was established. As a result, the critical impact velocity and the shot energy were got. Then, the paper separately studied the relationships among diameter of trachea, impact stroke and shot energy. It shows that the shot energy increases first and then decreases with the increase of the diameter of trachea, and increases linearly with the increase of the stroke. The method provides a reference for shot energy calculation, diameter of trachea and stroke determination.

Research on LQG Control of Spindle Vibration Based on Voice Coil Motor Actuator

Shi Zhongquan , Ye Wenhua

2016, 27(10):  1308-1314. 

Asbtract ( )   PDF (693KB) ( )  

References | Related Articles | Metrics

In order to overcome the serious shortcomings of vibration suppression effects while the passive dynamic vibration absorber deviated from its optimal state, for vibration control of spindle on low dynamic stiffness milling machine, an active control system of hybrid dynamic vibration absorber was designed. By taking the voice coil motor as the actuator, the displacements and velocities as feedback signals, the absorber suppressed spindle vibration by applying forces on cutting tool directly so as to suppress vibration of the spindle. Considering the drive characteristics of the voice coil motor, a dynamics model of cutter and spindle vibration of two degree of freedoms(DOFs) was established, the equations of system states were derived, and the vibration control model was simulated by using linear-quadratic-Gaussian(LQG) control methods. Finally, experiments were carried out in milling processes to control the spindle vibration in a CNC engraving and milling machine. Results show that the hybrid dynamic vibration absorber based on voice coil motor can effectively reduce spindle vibration by active LQG control. The vibration suppression effects based on velocity feedback are better than that based on displacement feedback. But the vibration velocity feedback can effectively reduce the resonance peak of high frequency, the system should real-time adjust active control parameters according to actual vibration feedback signals.

A Processing Method to Weaken End Effects of LMD Based on Difference Performance of Time Series

Du Dongmei, Zhang Zhao, He Qing, Li Hong

2016, 27(10):  1314-1319. 

Asbtract ( )   PDF (708KB) ( )  

References | Related Articles | Metrics

End effects occured at the ends of signals after calculating their envelope and mean value estimation with LMD algorithm. In order to weaken the influences, a continuation approach was proposed based on the difference performance of time series. It considered the signals as a discrete function, and judged the signal tendency by the signs of their first-order difference and second-order difference, determining the value of extreme points of continuation according to the specific situation.This new method was used to decompose the synthetic signals and test signals of rolling bearings with outer raceway faults and inner raceway faults, their results were compared with those decomposed by the LMD improved by mirror extension. Its good performance in decomposition validates the effectiveness of this new approach in signal analysis.

Data Model of Bearings for CNC Machine Based on Life-cycle

Yang Xiaoying, Xu Yandong, Sui Xin, Ma Wei

2016, 27(10):  1320-1326. 

Asbtract ( )   PDF (786KB) ( )  

References | Related Articles | Metrics

In view of a unified mode absent of the CNC machine bearing life-cycle date management, the demands for data relationships and integrated management of the CNC machine bearing life-cycle were analyzed herein, and the life-cycle data management mode was established. Using the method of multidimensional modeling, three stages of multidimensional data model about the bearings integrated design, manufacturing and operations were set up from aspects of data attributes, data structure, organizational constraints and the operation mechanism. Combined with the application examples, the CNC machine bearing life data management system was designed and the expected effectivenesses were achieved, which lays a theoretical foundation for data integration management of life-cycle of the CNC machine bearings.

Two-stage Multi-objective Ant Colony Optimization for Solving Logistics Web Service Composition

Fang Qinghua, Ni Liping, Li Yiming

2016, 27(10):  1327-1336. 

Asbtract ( )   PDF (866KB) ( )  

References | Related Articles | Metrics

A two-stage multi-objective ACO(TMACO) was proposed to solve logistics Web services composition optimization problems. First, to solve the time increases rised by candidate services which was dominated in the raw data, a pre-optimization strategy was proposed based on Pareto dominated ideology; secondly, since the weights of each attribute were difficult to determine, a non-dependent weight pheromone update strategy and inspiration information policy were included in the TMACO; and finally, the basic ACO was easy to fall into local optimum problem, a lazy ant strategy was proposed to solve this problem. The experimental results show that TMACO algorithm has good performance. Its optimization capability is better than that of the basic ACO,the improved ACO which used the distance of the solution and the ideal solution to update the pheromone,the basic genetic algorithm and improved genetic algorithm which applied the dominant factor to evaluate a solution, TMACO optimization algorithm has a higher ability to find more and better Pareto solutions.

Research on Optimization of FJSP Based on Maintenance Time Window

Zhu Chuanjun, Song Wenjia, Zhang Chaoyong , Cao Jing, Zhu Mengzhou

2016, 27(10):  1337-1343. 

Asbtract ( )   PDF (645KB) ( )  

References | Related Articles | Metrics

An optimization model was proposed to minimize the makespan in FJSP based on maintenance time window， which integrated the preventive maintenance. A hybrid algorithm was presented to deal with the model based on TLBO. A new machine sequence initializing strategy was investigated to optimize partial initial population based on “shortest processing time for operation”,  which might improve the quality of the initial solutions, so the computing process might convergence in a relatively short time. By calculating and comparing the results of FJSP benchmark problems with other literatures, the feasibility of the hybrid algorithm was proved on the whole. In view of flexible job-shop schedule optimization model which integrated maintenance time window, the data from the literatures was modified for the model and calculated by the hybrid algorithm. By comparing the results with other algorithms, the effectiveness of the hybrid TLBO algorithm was validated.

Topology Optimization of Large Crossbeam Based on Decomposition of Functional Sections

Wu Fenghe, Shi Hongliang, Xu Xiaopeng, Fan Junwei

2016, 27(10):  1344-1352. 

Asbtract ( )   PDF (866KB) ( )  

References | Related Articles | Metrics

According to the poor readability of a three-dimensional structural topology optimization model for crossbeam with complex load conditions and the difficulty to get an effective guidance on structure optimization, a decomposition of the functional sections topology optimization method was proposed. Based on the principles of decomposition and equivalence of forces, the three-dimensional solid was decomposed into two-dimensional functional sections in three planes. The properties of resistance to bend or torsion were determined according the stress modes of each functional section; then the two-dimensional topology optimization of each of the two main functional sections was analyzed. The topology optimization of the three-dimensional solid might be accomplished by integrating the results of the analysis. At last, the goal that converting 3D topology optimization into 2D topology optimization might be completed. The crossbeam of turning-milling machining center CXK5463 was used as an example to verify the effect of the proposed method. The simulation results show that: a clear stress transfer path may be got, keeping the static and a dynamic characteristics of the crossbeam stable. The total weight is reduced by 12.67%. The results of the topology optimization are obvious and the helpful instruction and reference may be provided for the topology optimization of large-heavy complex machinery by this method.

Study on Variation Regulation of Cutting Forces in Multi-edge Cutting with Flat End Mills

Liu Can, Wu Jingquan, Liu Huanlao, Tan Guangyu

2016, 27(10):  1352-1357. 

Asbtract ( )   PDF (556KB) ( )  

References | Related Articles | Metrics

For revealing the regularity of cutting force varying in multi-edge milling with flat end mills, the mathematical expressions of nominal cutting forces in horizontal directions were deduced, and these cutting forces were found to be harmonic functions of rotational angle, their constants were in proportion to the numbers of simultaneously cutting edges. With normalizing the coefficients of cutting force expressions, and applying simulation method, the dimensionless means and amplitudes at tooth frequency of nominal cutting forces for flat end mills with common flute were obtained. The simulation results show that: in multi-edge cutting, the means of nominal cutting force in radial depth direction prominently increases, while its amplitudes at tooth frequency either increase or decrease. Experiments of cutting and force measuring for 4-flute flat end mill were done, the results agree with those of mathematically deduction and simulation. Research results imply that, comparing with single-flute continuous cutting, the static cutting force in radial depth direction of multi-edge cutting will prominently increase; in horizontal directions, multi-edge cutting may be more or less stable; the multi-edge cutting with even-flute mills may be especially stable. Research results can be used in milling for selecting immersion angle optimally.

A Bionic Approach of Topology Optimization to Low Noise for Thin Plates

Teng Xiaoyan, Jiang Xudong, Shi Dongyan

2016, 27(10):  1358-1364. 

Asbtract ( )   PDF (713KB) ( )  

References | Related Articles | Metrics

Aimed at minimizing the acoustic radiation power of thin plates for noise reduction, a bionic approach of topology optimization was presented to address stiffeners layout of thin plates by co-opting the characteristic configuration of botanic venation branched structures. A primary vein growth of stiffeners was governed by minimal strain energy while a secondary vein growth of ones by releasing maximal shear stress. At each junctions, leaf veins were adjusted according to the general Murray criterion. Consequently an adaptive growth algorithm of stiffeners was established featured with hierarchical structure like leaf vein. Exemplifying the transverse bending vibration and resulting acoustic radiation for clamped thin plates, the acoustic radiation power and the distribution of vibrational power flow were analysed respectively for thin plates with stiffeners layout imitating botanic venation. The numerical results show that the stiffeners layout method to imitating botanic venation is superior to the orthogonal stiffeners layout method in vibro-acoustic characteristics subjected to the same volume constraints for stiffeners. Therefore the bionic layout method of stiffeners to noise reduction is valid or feasible for thin plates.

Numerical Research of Micro-pit ECM Based on Coupling Electric and Flow Fields

He Yafeng, Lu Wenzhuang, Gan Weiming, Yin Feihong, Wu Xiaofeng

2016, 27(10):  1365-1370. 

Asbtract ( )   PDF (804KB) ( )  

References | Related Articles | Metrics

Texture technology might reduce surface friction and wear of friction pair. A square micro-pit ectrochemical machining（ECM） as an object, the theoretical model of coupled field was established herein taking into account the mutual relationship of electric and flow fields in process. The distribution of coupling field potential, current density and volume fraction was obtained by using numerical methods, the relationship of inlet pressure and outlet maximum hydrogen volume fraction was discussed, thus it provides a theoretical basis for a square micro-pit ECM, At the same time, the square micro-pit ECM tests were done to obtain better test pieces.

View Planning in Line Laser Measurement for Self-occlusion Objects

Chen Tianfan, Gao Chenghui, He Bingwei

2016, 27(10):  1370-1376. 

Asbtract ( )   PDF (610KB) ( )  

References | Related Articles | Metrics

Focusing on measurement and 3D reconstruction of unknown self-occlusion objects, a new view planning method was proposed combining with fast reconstruction using Kinect Fusion technology and line laser precision measurement. Firstly, the surface depth information model of unknown self-occlusion object was obtained quickly with Kinect Fusion technology, and then the cross section shape of the object was analyzed. According to measuring visibility judgment of the five degrees-of-freedom line laser measurement system about left-right direction and upper-lower direction, the global view planning was carried out based on the best measurement range,the self-occlusion and point cloud holes were eliminated accurately and quickly. Finally, the 3D object surface reconstruction with high precision was obtained.The reconstruction experiments of self-occlusion object show that the method is feasibility and effective.

Analysis of a Novel Fully-isotropy 3T Parallel Mechanism

Cao Haofeng, Cao Yi, Qin Youlei, Ding Rui

2016, 27(10):  1377-1381. 

Asbtract ( )   PDF (528KB) ( )  

References | Related Articles | Metrics

To avoid the difficulties in the kinematics analysis and control brought by the existence of coupling in a PM, a novel kind of fully isotropic PM with three translational degrees of freedom was presented. This PM was connected by three limb chains between the moving platform and the fixed base. The first prismatic pairs of three limb chains were in orthogonal distribution, which made the moving platform of the mechanism have three translational degrees of freedom, and there existed a one-to-one correspondence between the input and output displacements. The mechanism’s most prominent advantages are simple kinematic pairs, three translations decoupled, simple kinematics analysis and to facilitate the mechanism motion control design. Using screw theory the degree of freedom and properties were analyzed and the active pair of the mechanism was determined. It also gave out the mechanism's forward and inverse position and velocity analysis, workspace and movement performance. According to the relationship of input and output, Jacobi matrix was solved and fully isotropic of mechanism was verified. Thus it provides a theoretical guidance to the further applications, and also has good application prospects.

A General Method for Multi-tooth Contact Analysis of Cycloid-pin Gear Transmission

Xu Lixin, Yang Yuhu

2016, 27(10):  1382-1388. 

Asbtract ( )   PDF (702KB) ( )  

References | Related Articles | Metrics

In order to effectively reveal the influences of tooth profile modification, elastic contact deformation and load variation on multi-tooth meshing contact dynamic characteristics of cycloid-pin gear transmission, a general dynamics analysis method was proposed based on the multi-body dynamics theory and elastic contact theory, which might be used to exactly predict the engagement number in cycloid-pin gear transmission, locate the contact point and get the contact load. A multi-rigid-body system of cycloid-pin gear transmission was modeled firstly. Secondly, at any moment of numerical calculation, the contact conditions between the discrete points on cycloid gear profile and pins were checked to meet the requirements or not. Then, the maximum contact depth was determined and the normal contact force was calculated. Finally, the contact force was converted to the generalized force, and the dynamics equations of the cycloid-pin gear transmission system with multi-tooth meshing contacts were formulated. The effects of profile modification, elastic contact deformation and load variation on multi-tooth meshing contact dynamics characteristics of a specific cycloid-pin gear transmission system were analyzed. The results indicate that the real numbers of pins to transmit load are determined by the characteristics of tooth profile modification and external torque. For the cycloid-pin gear systems with different transmission ratios, the estimation of the numbers of pins to transmit load and the calculation of contact force can be finished efficiently and accurately by this approach.

Fatigue Limit Test of Fusion-mouth Material of Extruded Aluminum Alloy Profile

Bai Xin, Xie Liyang, Tong Anshi, Li Ming, Tan Xiufeng

2016, 27(10):  1388-1392. 

Asbtract ( )   PDF (577KB) ( )  

References | Related Articles | Metrics

In order to determine fatigue limit of fusion-mouth material of extruded aluminum alloy, the L-shaped notched specimens and their fixture were designed under the circumstance that those materials might not be designed as the normal standard fatigue specimens due to their special positions and sizes. Firstly, stresses on different locations of the tested L-shaped notched specimens were solved using finite element method. Then, the maximum stresses were approximated by means of the numerical regression method. Thus, the relationship between test load and fatigue stress might be explained by an equation. In order to determine the fatigue limit of the located-in-fused-mouth materials of a kind of extruded aluminium alloy profiles, an up-and-down program was also tested for the designed L-shaped notched specimen by designed fixture, and the fracture samples were also analysed.

A Damage Model for Fatigue-creep Interaction Based on Entropy Increase Theory and Its Experimental Verification

Chen Ling, , Zhang Xianming, Liu Fei, Ouyang Ping, Liu Xianbin

2016, 27(10):  1393-1398. 

Asbtract ( )   PDF (597KB) ( )  

References | Related Articles | Metrics

According to the classical theory of thermodynamics, the fatigue-creep interaction damage of the material might be regarded as the accumulation of the entropy increase. When this accumulation reached to the critical point, the failure occured. From this theory, using the change of the entropy increase to describe the material damage, a damage model for fatigue-creep interaction was developed herein based on CDM and the law of energy conservation. To verify this damage model, the fatigue-creep interaction tests of 1.25Cr0.5Mo steel were conducted with the trapezoidal wave loading under stress control at 540℃ and 520℃. According to the tests, the change of the residual strain, which might reflect the accumulation of the entropy increase of the material, was defined as the damage variable. With this definition, the damage curves of different loading conditions were obtained by the above fatigue-creep interaction damage model. Results show that the damage values measured from experiments are in good agreement with these damage curves, which means that the damage model presented herein may describe the fatigue-creep interaction damage evolution well.

Effects of Different Arc Rates on Interface Behavior of Ni201 Repaired Layers by Electro-spark Deposition

Zhao Yuncai, Liu Zongyang, Yang Leilei

2016, 27(10):  1399-1403. 

Asbtract ( )   PDF (630KB) ( )  

References | Related Articles | Metrics

The key factor affected on the quality of the repaired layers was determined by the processing parameter selection of remanufacturing equipment. Ni201 repaired layers on Q235 steel surface were prepared by electro-spark deposition technology, the effects of different arc rates on the quality repaired layers were analyzed. The microstructure, chemical elements distribution and phase composition of the bonding interface between repaired layer and substrate were investigated by means of scanning electron microscopy and energy dispersive spectrometer, and X-ray diffraction. The results show that the value of arc rate is between 35%～45%, the microstructure of the repaired layers is uniform and dense, the interdiffusion of elements demonstrates that the repaired layer is bonded metallurgically with the base, the main phase of the layer is composed of Fe19Ni， Co3Fe7， Fe0.9Si0.1 and C0.055Fe1.945 .

Control of Hydraulic Steer-by-wire System Based on Torque Feedback and Positional Error

Diao Xiuyong, Lu Zhixiong, Jiang Chunxia, Zhong Wenjun, Zhang Peiyou

2016, 27(10):  1404-1407,1419. 

Asbtract ( )   PDF (585KB) ( )  

References | Related Articles | Metrics

Hydraulic steer-by-wire system included steering control and road-feeling generation control, the coordination of the system was very important. The paper analyzed the coupling connection of the two control parts, also the theory of bilateral control system, then a kind control method called torque feedback-positional difference  type control method was proposed, which combined position and torque informations. In this control method, the control signals of road-feeling motor were determined by differences between target road wheel angles and practical road wheel angles. Steering wheel angle divided by transmission ratio was target road wheel angle. In addition, the control signals of electron hydraulic proportional servo valve were determined by drivers' torque, and the bench tests were finished. The results show that the steering reversal time is as 0.5s, the difference of step response is as 0.231° and response time is as 2.265s, the sine response difference is below 1.401°, and random input difference is smaller than 4.492°, but when steering orientation changes, the difference is up to 12.376° with continuous time of 0.15s.

Analyses of Radial Stiffness and Damping Model for Mechanical Elastic Wheel

Wang Qiang, Zhao Youqun, Du Xianbin, Fu Hongxun

2016, 27(10):  1408-1413. 

Asbtract ( )   PDF (556KB) ( )  

References | Related Articles | Metrics

In view of the stiffness characteristics of the new mechanical elastic wheel, an elastic foundation closed circle curved beam model was established by curved beam theory. The relationships among the wheel stiffness and the elastic foundation stiffness of hinge group, bending stiffness of elastic wheel and excitation frequency were analyzed. Based on the static and dynamic test analysis results of wheel, the correctness of the curved beam model was validated, the numerical analytical relations among the wheel stiffness and deformation, deformation rate, excitation frequency were analyzed. The nonlinear analytical model for wheel stiffness and damping was established, and it could reflect the nonlinear effects of the wheel deformation, deformation rate and excitation frequency on the stiffness and damping. It provides a grounds for the further studies of vibration of the wheel structure.

Dynamic Sliding Mode Control of AMT Gear-selection and Shifting Electric Motors

He Xiong, Zhang Nong, Kong Guoling

2016, 27(10):  1414-1419. 

Asbtract ( )   PDF (576KB) ( )  

References | Related Articles | Metrics

Modeling and analyses were carried out on a electric AMT, in order to assuage the long gear selection and shifting time problem of AMT. Based on the theory of sliding mode control, gear selection and shifting dynamic sliding model control was initiated, which was applied in the position track of gear selection and shifting mechanism. Both of the simulation and experimental results reveal that compared to the general PID controller and sliding model controller, dynamic sliding model controller has faster response, better robust, higher track accuracy, which improves the shifting quality of electrical AMT.