Table of Content

10 August 2010, Volume 21 Issue 15

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Analysis of Shell Structural-acoustic Coupling Based on Smoothed Finite Element and Finite Element Method

TAO Ling-Yun, XU De-Ge, CANG Xian-Guo

2010, 21(15):  1765-1770. 

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In order to improve the accuracy of simulation analysis on shell structural-acoustic coupled systems, a smoothed finite element method (SFEM) was extended to solve the shell structural-acoustic coupled problems, and the formulation of coupled SFEM/FEM was presented for the shell structural-acoustic coupled systems. The governing equations of a structural-acoustic system were expressed in displacement formulation for the structure and in pressure formulation for the fluid. The cell-based strain smoothing technique was performed for structure domain, and the bending stiffness matrix and membrane stiffness matrix were obtained accurately and rapidly, and the standard FEM model was used for acoustic domain. Numerical examples of a box structural-acoustic coupled model and a simple micro-car structural-acoustic coupled model were presented to show that SFEM/FEM achieves higher accuracy as compared with FEM/FEM for structural-acoustic problems. 

Research on Pulley Deformation of Metal Belt CVT

ZHANG Wu, ZHOU Chun-Guo, LIU Kai

2010, 21(15):  1771-1774. 

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Pulley deformation is one of the factors affecting transmission efficiency of metal belt CVT. It leads to the cause of the metal belt deflection, intensifies whole-part abrasion and reduces the life-span of the CVT. The pulley deformation was analyzed by finite element software ANSYS herein, determined the mesh partition mode when NDIV No. of element division is 20, the results indicate that with the increase of transmission ratio, the driving pulley deformation decreases, stress is increases after reduces for a while, and the driven pulley deformation and stress increase. The results from finite element analysis are in agreement with those from other’s experimental data, whereby demonstrating that the established finite element model is rational and that the analysis results are reliable.

Path Checking in Curved Component Ultrasonic Inspection

LI Xiong-Bing, YANG Yue, HU Hong-Wei, NI Pei-Jun, YANG Cheng

2010, 21(15):  1775-1779. 

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component with curved surface; ultrasonic inspection; path checking; projection

Development of Control System for Multi-wire Saw

JIANG Jin, DAI Yu-Xin, BANG Sai-Ji

2010, 21(15):  1780-1784. 

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The overall structure of multi-wire saw was analyzed and its work principle was explained. The realization diagram of hardware and software was given for control system. Two difficult problems which were tension control and multi-motor synchronization were mainly studied. A electromechanical integration of tension control scheme was designed. Tension was exerted by means of a servo motor instead of a heavy hammer. The real-time position was feedbacked by absolute value encoder of the servo motor. The speed of supply/collect spool motor was adjusted for keepping wire tension stable. The multi-motor control structure was analyzed. A multi-motor synchronization motion model was established. Synchronization motion was achieved by using virtual main axis and model-free adaptive control. Experimental results indicate that multi-motor synchronization control is good and tension control is stable. It shows that the proposed scheme is correct and feasible.

Optimal Design of Flywheel Hub Structure for High-temperature Superconducting Magnetic Energy Storage Flywheel

WEI Hua-Min, SHANG Ji-Jiang

2010, 21(15):  1784-1787. 

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This paper introduced an optimal design method of a high-temperature superconducting magnetic energy storage flywheel hub. The finite element models for the flywheel hub were established based on the finite element theory. Then the optimal design was done through topological optimization, material selection, shape optimization etc. The results show that the optimal energy storage density of hub is increased by 7.6%.The method improves the design efficiency of the rotor, and has important values in optimal design of the flywheel.

Mathematic Model of Elliptic Curve to Grind Stone Sculpture with Multi-axis Control

CHEN Wei-Xu, ZHANG Ji-Yu

2010, 21(15):  1788-1793. 

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The complex surfaces on a sculpture was fitted with elliptic curves in sets based on the surface nodal points and the elliptic fitting algorithm was presented. By controlling the rotating angle of the grinding disc so as to make the effective grinding surface in elliptic trace, the elliptic surfaces on the sculpture were ground in 5-aixs control rapidly and accurately. The control trace in 5-axis movement for the grinding point was designed, and the mathematic model for the multi-axis control was deduced and established and the control mode was also proposed. The actual grinding test indicates that the proposed elliptic fitting algorithm and the mathematic model for the multi-axis control and the control mode are feasible to grind complex surface on stone sculpture automatically.

Design and Optimization of Balancing Mechanism for a Parallel Machine Tool

MENG Xiang-Zhi, LI Shu-Jun

2010, 21(15):  1794-1797,1839. 

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The distribution law of a parallel machine’s potential energy was simulated and calculated.According to this,a balancing mechanism of the machine was designed.The structure parameters of the balancing mechanism were optimized.The max force of driving chains remains only 13.7% after balancing.So the balancing effect can be considered as good.This balancing mechanism is very simply,easy to actualize and effect well.It can be as a reference to other similar machines’ balancing.

Design Principles and Practical Applications of Sensor Used to Measure Instantaneous Angle Velocity Based on One Tooth Difference

HAN Shao-Jun, ZHANG Bing-Wei

2010, 21(15):  1798-1800. 

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A method using the principle of one tooth difference was used to measure cycling instantaneous angular velocity herein.The measurement method can extend the computer reading time interval, reduce the required encoder resolution, reduce manufacturing cost of sensors and increase the measurement accuracy. A practical example to measure the instantaneous angle velocity in the chain transmission was given to prove the theory.

Research on Vertical Vibration of Hot Rolling Mill

FAN Xiao-Ban, CANG Yong, WANG Hui-Gang

2010, 21(15):  1801-1804. 

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The nonlinear dynamic model of rolling mill vertical vibration was established by introduction to Duffing oscillator and the parametrically excited stiffness. A cubic function hysteresis model of strip was choosen by contrasting the simulation and the measured results. From the simulation results, it shows that the roll amplitude appears bifurcated under certain conditions, and the vibration presents chaos. Through the time-frequency analysis of measured data, it shows that the value of vibration frequency and its spectrum have significant changes over time. And there are harmonic resonance or combination resonance. It also shows that the vertical vibration system has non-stationary and chaotic characteristics by correlation dimension and largest Lyapunov exponent calculation.

Virtual NC Machine Tool Technology Based on Constrain and Dimension Driven

WANG Fu-Yuan, XU Jia-Wen

2010, 21(15):  1805-1808,1819. 

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Real-time Scheduling Algorithm with Fault-tolerance in Numerical Control Systems

DING Mo-Fu, GUO Dui-Feng, QIN Cheng-Gang

2010, 21(15):  1809-1815. 

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According to the characteristics of hybrid task set and high dependability of numerical control systems, a fault tolerant real time scheduling algorithm based on software fault-tolerant model was proposed to dispose of system transient faults. In order to provide the maximal execution time for the primaries, the FT-MT algorithm reserves time intervals as late as possible for all the alternates before their deadlines. At the same time, for the sake of preventing early failures in execution from giving rise to failures in the subsequent tasks, an executive rule for primaries was added into the FT-MT algorithm which improved the predictive quality of the primaries remarkably. The simulation experiments show that the FT-MT algorithm has much better fault resilience than that of the well-known algorithms so far.

Research on Method of Regionalization Design in Context for Helicopter Digital Mock-up

CHEN Yang-Beng, GAO Liang, WANG Chen, XIE Jiang, DING Qiu-Lin

2010, 21(15):  1815-1819. 

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In order to improve helicopter collaborative design, a method of regionalization design in context for DMU was proposed and the system frame for implementation of the method was designed. Based on the characteristics of helicopter development, the expression model of DMU regionalization based on hierarchical tree of axis aligned bounding box (AABB) was proposed to search the DMU region; the relationship graphic of model link (RGML) was proposed to express the relationship of model link (RML) in DMU, and the impacts of correlative models in context can be analyzed effectively. The method was used to develop some helicopters, the accuracy rate of models search and the efficiency of models loading from whole helicopter DMU are improved, and the cycle of sub-system optimization and part change is shortened. 

Parameter-driven Configuration Design Method in Mass Customization

AI Hui, MO Li, XIONG Ben-Fan, CHEN Li-Beng

2010, 21(15):  1820-1824. 

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In order to improve the efficiency of product configuration design in mass customization, a parameter-driven product configuration design method was put forward. In the presented method, parametric configuration unit (PCU) encapsulating all components that are similar to each orther in function, performance, structure, geometry and other characteristics expressed by parameters was as the basic element for building a product structure model, and the parameter-drive rules that represented the product configuration knowledge as constraint relations between characteristic parameters was defined. Then, a rapid configuration process based on recursive algorithm was illustrated. Finally, a fire door product case was given to verify the feasibility of the method.

Optimization of Secondary Structure of Linear Induction Motor in Urban Rail Transit Based on Response Surface Methodology

WANG Li-Jiang, LEI Qin-Fen, XIE Yun-Yue

2010, 21(15):  1825-1830. 

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A 3D finite element model (FEM) of SLIM in urban rail transit was built. The influence between the secondary structural parameters and starting force characteristics of SLIM was analyzed by parametric analysis of secondary structural parameters. Two parameters, secondary aluminum thickness and secondary width, were selected, which greatly influenced on the starting force characteristics of SLIM. The RSM of starting force characteristics was built based on NN, which only needed few parametric analysis of 3D FEM. Based on the RSM of SLIM, a multi-objective optimization of secondary structural parameters was carried out via multi-objective genetic algorithm (MOGA), which choosen secondary aluminum thickness and secondary width as design variables, and choosen maximum starting thrust force and minimum normal force as optimization goals. Then the selection method of the secondary structural parameters was proposed. The effectiveness of the method was verified by simulations and experiments.

Development of Underwater Intelligent Cleaning Robot for Large Condenser

SHU Jiang, WANG Yao-Na, TU Hong-Shan, HU Hai-Xia, LIU Li

2010, 21(15):  1830-1835. 

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Aiming at online efficient cleaning for condensers used in units whose power capacities are above 120MW , a underwater intelligent cleaning robot was proposed. Based on the working environment of the condensers, the robot system structure was designed, which consisted of traveling mechanism, the pipe for water supply and wire, and drive mechanism for robotic arm. Then the physical prototype was developed. Visual serving arithmetic was adopted to achieve the automotive localization condenser tube control. The experimental results demonstrate that the robot can approximately satisfy the basic requirements of automatically cleaning condenser. It can also be widely applied in many fields such as power industry, chemical plant, pharmacy, etc. Besides, it has great effect on promoting large-scale and safe production, energy saving as well as consumption reduction.

Research on Topology Optimization Design for Support Structure

FANG Zi-Fan, YANG Lei, DU Dao-Jia, HE Kong-De, ZHANG Ge

2010, 21(15):  1836-1839. 

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Taking support structure as the object, multi-objective optimization for optimun layout of structural materials and for natural frequency maxinaization under multiple load cases was studied. Based on the SIMP (solid isotropic material with penalization) method, a compromise programming method was adopted to define objectives of multi-objective topology optimization.With the support structure for the study,a topology optimization model was established, using the analytic hierarchy method to determine the weight of each sub-goal, the multi-objective topology optimization was conducted,the layout was optimized,and the natural frequency was raised.The results of analysis show that the topology optimization process is a suitable solution to the optimization of plate and shell structures.

Film Pressure Characteristic Analysis of Squeezed Film Damper

ZHANG Juan-Hua, SHANG Jun-Lang, XIONG Zhi-Wen, HU Ying

2010, 21(15):  1840-1843. 

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It set up the kinematical equation of a new type metal rubber squeezed film damper's rotor system based on the D’alembert principle herein. From the equation, it deduced the mathematical expression of the relative eccentricity of the rotor system. By contrast the film damper pressure distributing characteristics were analyzed between the traditional squeezed film damper and the new type metal rubber squeezed film damper. It proves the new type metal rubber squeezed film damper presents characteristics as film stiffness changing with linearity even under the large eccentricity ratio range, which can effectively improve the nonlinearity characteristics of the film stiffness of the traditional squeezed film damper.

Investigations of Grinding Forces for Grinding Cemented Carbide with Brazed Diamond Wheels

DAN You-Ji, LI Yuan, HUANG Hui, XU Xi-Feng

2010, 21(15):  1844-1849. 

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Grinding forces were measured in the grinding of two typical cemented carbides with a vacuum brazing diamond wheel. The specific normal force, tangential force and the grinding force ratio acted on the grinding wheel were investigated based on the measurement data. The theoretical models of the forces per grain with the grinding process parameters were established, which were verified by experimental data. The different influences of depth of grinding, feed rate and circular velocity of the grinding wheel on the specific grinding forces, the forces per grain and grinding force ratio were explained theoretically.

Experimental Study on Characteristics of Spatial Distribution of Airborne Dust in Machining

LIN Fan, LIU Fei

2010, 21(15):  1849-1854. 

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After analyzing the mechanism and influence factors of generation and dispersion of the machining dust, the present work proposed to use relative indexes to describe the characteristics of spatial distribution of the dust. Experiments were designed and conducted to measure the dust concentrations at several different spatial spots during machining processes at different cutting speeds near the machine tool. The intuitive contour lines of the concentrations were acquired through the data processing by cubic interpolation. And the CV(coefficient of variation) for the data at different direction or at the individual direction but different distance away from the cutting spot were calculated. The numerical analysis shows that the spatial concentration distribution of the dust has obvious directivity and gradient when the cutting speeds are low, while the dust concentration is relatively homogeneous at all the direction and the gradient is small when the cutting speeds are high. This finding will be used as a reference for the dust controlling. 

Optimization Study on Influence of Spiral Medical Micro-robot’s Structural Parameters on Injury to Human Intestinal Wall

LIANG Liang, TANG Yong, LONG You-Xia, HU Guan-Yu

2010, 21(15):  1855-1859. 

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A non-invasive spiral medical micro-robot was introduced. When it was driven in the human intestines, dynamics control equations of intestinal fluid were established. By computational fluid dynamics method, the relations between different robotic structural parameters (angle α, the ratio between groove face width and pitch β1, the ratio between groove bottom width and pitch β2, the ratio between groove depth width and radius clearance γ, spiral angle Φ and thread number n) and impact pressures of human intestinal wall produced by the micro-robot were calculated and analyzed in the circumstances of cylindrical forward and reverse rotation. The optimal robotic structural parameters were obtained. The above theoretical analysis results provide an essential theoretical basis for the optimization design of a high-speed rotating spiral medical micro-robot really applied to non-invasive or mini-invasive surgery of human intestines.

Stacking Sequence Optimization Method Based on Cured Deformation of Composites

LONG Jie, JIN Hai-Bei

2010, 21(15):  1859-1863. 

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This paper imported agent model which represented the stacking sequence. Then the stacking sequence parameters, buckling eigenvalue and cured deformation with different stacking sequence were analyzed by numerical experiments. Then, the response surface models of cured deformation vs stacking sequence parameters and buckling eigenvalue vs stacking sequence parameters were constructed separately. Further, the optimization of cured deformation was constructed to find the best stacking sequence parameters. Lastly, the actual stacking sequence was gained by a stacking sequence reverse design on the related stacking sequence parameters. The results show that the optimization method of stacking sequence can reduce the cured deformation subjected to stability constraint, and can improve the efficiency of optimizing the stacking sequence based on the agent model observably.

Experimental Study on Micro-backward Extrusion of a Zr-based Metallic Glass in Its Super-cooled Liquid Region

TUN Xiao, LI Jian-Jun, ZHENG Zhi-Tian, ZHOU Hua-Min

2010, 21(15):  1864-1868. 

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The superplastic micro-forming of Zr55Cu30Ni5Al10 bulk metallic glass in its super-cooled liquid state was studied by employing micro-backward extrusion experiments. Crossover experiments were carried out under different temperatures (705K~735K, at an interval of 5K) and different punching speeds (2~8μm/s, increasing by 1μm/s). The extrusion parameters and the influencing factors of forming process were discussed. The results reveal that the micro backward extrusion process can be divided into four stages. The depth of extruded parts increases with the increase of temperature and the decrease of punching speed, and the depth is more sensitive to temperature at the range of 710~725K. The part will crystallize when formed at low punching speed or high temperature. The best parameters for the extrusion are at the temperature of 725K and the punching speed of about 6μm/s. Micro cup-shaped parts with wall thickness of 0.1mm and 0.05mm are successfully extruded under this condition. The SEM results show that the parts have flat edges and well replicate the mold size.

Design Calculation Method for Autofrettaged External Pressure Cylinders

SHU Rui-Lin, SHU Guo-Lin

2010, 21(15):  1869-1874. 

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The basic theory on autofrettage of external pressure cylinders was established on the basis of the analytic solutions of elastic-plastic stresses of an external pressure cylinders derived herein according to Tresca yield criterion and then proposed a design calculation method for the external pressure vessels. It is also shown that although the elastic and the elastic-plastic stresses of the external pressure cylinders are different from those of the internal pressure cylinders and their residual stresses after removing autofrettage pressure also differ from each other, the equivalent stress of residual stresses, the equivalent stress of the elastic stresses caused by operation pressure, the equivalent stress of the total stresses and the equivalent stress of the elastic-plastic stresses of the external pressure cylinders coincide with those of the internal pressure cylinders.Thus the solutions to the autofrettage of external pressure cylinders are identical with those to the autofrettage of the internal pressure cylinders.

Influence of Die Surface and Punch Style on Forming Effects of SS304 T-shapes by Hydroforming

GUO Xun-Zhong, DAO Jie, LI Ming

2010, 21(15):  1875-1878,1889. 

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The effects of die surface and punch on the forming quality of T-shapes by hydroforming were investigated by means of the numerical simulation. The forming effects of different loading paths in the process were investigated. Subsequently, a practical hydroforming was performed based on the simulation results with the aid of special lubrication coatings. It is obviously indicated that the simulation results agree well with the experimental ones in protrusion height and wall thickness distribution. The results show that the better die face and the punch can improve the quality of T-shapes effectively.

Study on Protection Performance of a New Kind of Safety Belt for Pregnant Occupants

CAO Li-Bei, XIAO Kai-Yan, XIAO Hui-Jing

2010, 21(15):  1879-1884. 

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A new kind of safety belt combined with the traditional 3-point belt for pregnant women was presented. A detailed 30-weeks pregnant uterus was modeled by finite element method. A pregnant occupant model with gestational age of 30-weeks was developed based on the 5th percentile female facet model. The model was validated via abdominal response corridors under rigid bar loading and belt loading. The new kind of safety belt was also modeled by finite element method. In order to study the injury of pregnant occupants, a series of front impact simulations with different impact velocity and configuration of safety belt were conducted using the pregnant model and safety belt model. The results indicate that the new kind of safety belt can prevent the lap-belt from moving upward and reduce the energy of uterus rushing forward, and then decrease the strain at uterus-placental-interface(UPI) significantly. It will not decrease the protective effects of the traditional 3-pt belt on the maternal. In addition, the best protection can be obtained by using the enwrapping fabric whose prolongation ratio was 14.5%. 

Research on Enhancement Coefficient of Automobile Electrical Connector Lab Reliability Test on Vibration

CHEN Jian, XIU Lei, MA Wen-Meng, LIU Bing, LI Jing

2010, 21(15):  1885-1889. 

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In order to study the reliability of electrical connector under combined electrical stress and vibration stress, an automobile electrical connector lab test on vibration was done by time-domain replication’s technology of real vehicle road’s signals.

Because there is not requirements of real vehicle road’s signals in national standards, then the enhancement test’s time can not be determined and the test results can not be appraised. These problems can be solved with enhancement coefficient and evaluation methods of the whole automobile’s quality. According to Miner’s rule of materials, mathematical model of enhancement coefficient K could be obtained,which was expressed with τ. Distribution of amplitude in time-domain can be got by rain-flow counting method. Fatigue index m of electrical connector’s materials can be got by sine test which is requested in national standards, enhancement coefficient obtained herein is identical with that on Proving Ground. Failure’s miles and the time of enhancement test can be got with enhancement coefficient. The results of the test can be appraised by failure’s miles.