Table of Content

10 March 2010, Volume 21 Issue 05

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Applications of Robust Probabilistic Optimization in Occupant Restraint System Development

ZHANG Jia-Hong, LI Guang-Yao, GAO Hui, CHEN Chao

2010, 21(05):  505-509. 

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A mathematical model of occupant restraint system of a mini-bus van in frontal impact based on software MADYMO was established. Based on that, the optimization process was conducted by conjuncting design of experiments, response surface method and robust probabilistic optimization design. The chosen design variables during this optimization were webbing stiffness, upper slipping position of the seat belt, the tearing force and the adding length. By applying the robust design, this method can reduce the sensitivity of design point and control the fluctuation of the design objects. Consequently, this will conduce to improve the quality of the products. The analysis results indicate that this method realizes the optimization of the design object, and enhances the reliability of the design parameters and the robustness of the objective function, which will make significant improvement in the engineering applications. 

Analysis of Friction Torque of Sensitive Ball Bearing under Low Speed

JIANG Chao-Na, CHEN Xiao-Yang, GU Jia-Ming, SHU Li-Ming, CHEN Xue-Jin

2010, 21(05):  510-514. 

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The starting friction torque and dynamics friction torque of a sensitive ball bearing under low-speed are much more important factors for the attitude control of navigation system. Generally, its operating condition is under the low-speed and thin oil lubrication, so the viscous friction was usually neglected and the friction torque caused by main influencing factors of elastic hysteresis in rolling, spin of rolling element and sliding friction on contact zone were considered. Based on the models of imitating statics，the location of pure rolling lines on the contact ellipse was calculated to estimate the friction torque of sensitive ball bearing. By comparison of theoretical results with both of the other theory analysis and test study, the feasibility of this model was qualified and structure parameters, such as the cofficients of inner and outer race curvature were discussed, which have influences on the friction torque. 

Optimization of Thickness Distribution of Unconstrained Damping Layer Based on Mode Shapes

CANG Xian-Guo, XU De-Ge, TAO Ling-Yun, YAN Re-Lei

2010, 21(05):  515-518. 

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Placement location and thickness distribution of unconstrained damping material affect the amplitude of vibration response of the base structure significantly, aiming at the problem of optimum thickness distribution of unconstrained damping material, a thickness distribution optimization method was presented based on mode shapes. In this method, the thickness distribution function was defined using a linear combination of a group of mode shapes absolute values, and the thickness distribution of unconstrained damping material is optimized by changing the mode shapes contribution factors. Optimization of thickness distribution of unconstrained damping material was studied under constant damping material volume. The numerical example shows that in contrast to uniform distribution of damping material, the optimal thickness distribution of unconstrained damping material controls the structural vibration more effectively and improves the utilization of damping material.

Study on Surface Morphology and Chip Formation by High-speed Milling of High Volume Fraction SiCp/Al Composites

XU Xiao-Lin, HUANG Shu-Chao, DIAO Wen-Zhen, ZHOU Li, ZHOU Jia-Lin

2010, 21(05):  519-524. 

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In order to study the cutting mechanism and workpiece surface morphology,high-speed milling tests were carried out on the SiCp/Al composites with higher volume fraction and larger particles by using PCD tool at dry and wet machining conditions. The results show that the dry machining condition is slightly better than that of the wet, whether the machined surface topography and microstructure of workpiece, or the chip formation and shape. Under the two kinds of cutting conditions, better surface roughness can be obtained.

Research on Method of Topology Optimization Design of Continuum Structures for Manufacturing

WANG Meng-Jiang, LI Chi-Che

2010, 21(05):  524-528. 

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In order to solve the engineering application problems of topology optimization, a method of the classification topology optimization for manufacture was presented, in which topology results for requirements of design and manufacturing can be also guaranteed. Meanwhile, for removing the instability coefficient, a hybrid density and sensitivity with Gaussian function filtering algorithms was proposed. The new filtering algorithm is easy to implement and has a good universality, which can solve numerical instabilities well and obtain good results of the optimization. Utilization of hierarchical topology optimization methods and related algorithms, the classical examples were calculated and compared the results of solution to verify the feasibility and effectiveness of the proposed method.

Design of Parameters and Analysis of Torque for Permanent Magnetic Epicyclic Gear Drive

SHU Hua-Jun, HU Li-Zhong

2010, 21(05):  529-535. 

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A permanent magnetic epicyclic gear drive was presented, and its geometry and kinematics were analysed by applying the principles of epicyclic gear drive and electromagnetics integratively. The torque equations between the sun gear and the epicyclic gear and that between ring gear and epicyclic gear were deduced using equivalent current model. The calculation and analysis of driving torque was achieved. Changes of the driving torque along with the number of pole-pairs on magnetic gear, center distance, axial thickenss, radial thickenss were discussed. Based on the results analysed above, the parameters of this permanent magnetic epicyclic gear drive were selected rationally.

A New Dynamics Modeling and Simulation for Eccentric Cam Mechanism

ZHANG Jin-Fu, ZHANG Dun-Long

2010, 21(05):  535-539. 

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 In order to investigate dynamics characteristics of eccentric cam mechanism more exactly, establishing dynamics model of the mechanism with considering some practical factors is needed. A new dynamics equation for eccentric cam mechanism with considering the friction between the cam and the follower and flexibility of the camshaft was established by using the finite element method and Lagrange approach. Taking this equation as mathematics model, the motion response of the mechanism was studied by using numerical method. According to the motion response obtained, the effects of the friction between the cam and the follower with the flexibility of the camshaft on the motion of mechanism were analyzed, and some correlative conclusions were obtained. It is shown from the conclusions that considering the factors of the friction between the cam and the follower with the flexibility of the camshaft is needed.

Research on Layered Network Planning Model Based on Large-scale and Complex Products

XU Jian-Ping, GUO,GANG,LUO Yu, LI Gao

2010, 21(05):  540-544. 

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Based on deep analysis of the characteristics in the assembly process of large-scale and complex products, this paper proposed a way of optimizing assembly bill of material(ABOM) by assembly cell. On this basis a mode of extensible layered network planning for assembly cell and assembly sequence was provided. The mode can supervise the production arrangement of components based on assembly cell, and supervised complete set of components of under assembly operation entrance. Through layered network planning the stability of upper production planning can be enhanced, at the same time the flexibility of performance and adjustment for underlying assembly sequence schedule can be advanced. Now the layered planning mode has implemented under software platform of project management.

Research on Intelligent Assembly System for Spacecraft Cabin

BANG Chao, LI Shi-Ji, XU Chi, LIU Xiang

2010, 21(05):  545-549. 

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An intelligent assembly system was proposed by means of computational intelligence, human intelligence and machine intelligence to solve the assembly problems of spacecraft cabin. Assembly sequence of the inner parts was programmed and optimized by ant colony intelligence algorithm, which simplified the difficulty of the assembly planning of complex structures. A virtual assembly certification and training solution was presented by the mixed reality technology, from three aspects of vision, information and operations to improve the efficiency of human-computer interaction. Moreover, the combination of human-computer intelligence carried out virtual verification for the assembly process of the module. Method of visual assembly quality inspection provides an effective guidance for the inspectors and helps them find remainders quickly, reduces the chance of missing reminders. 

Simulation and Experimental Analysis for High-speed Spindle with Water-cooling System

CHEN Wen-Hua, HE Jing-Chuan, HE Jiang, LIU Hong-Zhao, XIE Jun, NIU Jing-Po

2010, 21(05):  550-555. 

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A general applicable method for simulation of the fluid state and the thermal distribution was applied based on the software of ANSYS CFX. By changing the boundary conditions in FE mode of water-cooling system, temperature-rise was analyzed and compared according to different flux for cooling water, operation conditions, ambient temperature conditions. The research indicates that when the flow model is intense turbulent-flow, the k-ε dominated equation used to solve the conjugate heat transfer equation is an effective method, the greater the flux of cooling water and the smaller the temperature-rise; when the cooling water velocity increases to a critical value, the temperature rise is unable to be effectively controlled by increasing the flux of cooling water, the ambient temperature has little influence on temperature rise. 

 

Machining Feature Recognition of Complicated Part Based on Modeling Process

LI Wei-Beng, ZHENG Lin, GONG Zhi-Hui

2010, 21(05):  556-562. 

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There exist problems of complicated topology analysis and difficulty in intersection features recognition for complicated parts. A novel feature recognition method based on part modeling process which was recorded by way of macro command in CAD systems was proposed herein: geometry and topology entities which produced by single modeling process were analyzed in the single feature recognition process and all features in part were recognized based on step by step strategy.The limitation which the entirely geometry and topology entities should be analyzed in traditional method can be avoided. In order to offer a novel design method for intelligent interface for CAD/CAPP, the algorithm for input data acquirement and arrangement, feature hint recognition based on two-dimensional sketch, and feature parameter acquirement were mainly discussed.

Research on Territory Classification Method for Strip Surface Defect Recognition

WANG Yong-Hui, YA Yun-Hui, DIAO Da-Xin, DIAO Jiu-Liang

2010, 21(05):  562-566. 

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In response to the dilemma for pattern recognition by single classifier toward strip surface defects, a novel classification algorithm territory method was proposed.This method is simple, less time consuming, higher recognition accuracy and adaptability. The experimental study on classifying strip surface defects was presented, and the results show that the defect classes are with complex features, even the overlapping class border. The classification results are satisfactory.

An Algorithm of Sampled-data Linear and S shape Acceleration and Deceleration for CNC Controller

CHEN You-Dong, WEI Hong-Xin, WANG Qi-Kuai

2010, 21(05):  567-570. 

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A new method of sampled-data linear and S-shape acceleration/deceleration for industrial robots and CNC machine tools were put forward, which eliminated the running stage at low speed for a long time after deceleration because the actual deceleration point did not overlap the theoretical deceleration point. The velocity of iterative formula for acceleration/deceleration was proposed. The velocity was recalculated based on the acceleration so that the distance was exactly the integral times of the velocity. The acceleration and jerk was recalculated based on the velocity. It avoided the prediction of the deceleration point by every sampled time. The simulation and experimental results demonstrate that the proposed method can eliminate the running stage at low speed for a long time and significantly improve the productivity by avoiding the prediction of decelerating point.

 

Adaptive Edge Enhancement Method for Steel Strip Surface Defect Image

WEI Yu-Lan, YA Feng, YA Yun-Hui, LI Bing

2010, 21(05):  571-574. 

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According to neighborhood information an adaptive double-reciprocal filter was proposed to improve the edges which were degraded by denoising. In this method, geometric vicinity and photometric similarity were combined to filtering. In order to improve the effect, an edge related gradient coefficient was also chosen, which adaptively adjusted the original distance variance and brought a big weight in the background to remove the noises and enhanced the smoothness. On the contrary, a small weight was brought in the edge area. The blurriness of the edge can be obviously avoided by the proposed method. The experimental results show that this method is effective to eliminate the noises, and the edge detection is significantly improved.

Dynamics Analysis of Vacuum-pressure Infiltration Process of High Temperature Self-lubrication Composites with Sweat Gland Structure

WANG Yan-Jun, LIU Zuo-Min, YANG Li-Ying, WANG Shou-Ren

2010, 21(05):  575-580. 

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Principles of molten solid lubricants infiltrating micro-porous preforms were analyzed. The infiltrating saturation expressions and the infiltrating pressure expressions were educed by statistical analyzing the pore characteristics of micro-porous preforms and dynamics analysis of vacuum infiltrating process. Main influence factors on infiltrating quality and infiltrating process were discussed. And some problems for instruction and foundation of future experiments were studied. Based on the dynamics analysis of molten solid lubricant infiltrating micro-porous preforms, the infiltration technology parameters were ascertained reasonably. The detailed experimental results demonstrate that a new type self-lubrication composite with sweat gland structure can be fabricated by infiltrating TiC-Fe-Cr-W-Mo-V preforms with 60Sn40Pb-10Ag-0.3RE lubricants.

Tolerance Design and Application for Machine Tool Based on Geometry Error Source Compensation Each Other

HUANG Jiang, ZHANG Gen-Bao, LIN Xian-Lin

2010, 21(05):  580-584. 

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According to the phenomenon where the final results caused by geometry error sources of machine tool system should counteract each other, a new method to tolerance the machine tool was proposed, by which the geometry error sources should counteract reciprocally. This method took the economical machining precision as the original cost ambit, and realized the transform from the tolerances of geometry error sources to the final output precision on the machine tool by error modelling. According to the changed results on value and direction, the directions and values of some error source tolerances were adjusted purposefully to achieve a good effect which the geometry error sources counteracted each other in the sensitive direction of machining errors. Taking the YK3610 gear hobbing machine as an example, its basic steps and key problems in application was introduced.

Topology Optimization for Structural Design of Airplane Flutter Model

YANG Rui, YANG Xu-Yi, ZHANG Ying-Ying, LIN Chi

2010, 21(05):  585-588,594. 

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Optimal structural design was presented for airplane flutter models.It is a reverse problem for proper natural frequencies as well as structural similarity.The difficulty lies in the achievement of structural similarity,as the holes in optimal structures are irregular.Therefore,regular geometrical constraints were introduced.Then,BESO combined with element’s properties changing method(EPCM) and sensitivity

redistribution method(SRM) were used.An optimal structure with regular holes was obtained.Checkerboard pattern and local mode were significantly suppressed.An example of an airplane construction panel was provided.It is showed that the proposed approach is feasible for the design of structures with given natural frequencies.In addition,the optimal structure is similar to the original fuselage.

Study on Mechanics Properties and Size Effect of Monocrystalle Silicon Using Discrete Element Method

JIANG Qing-Jiang, TAN Huan-Jiang, LI Cai, YANG Dong-Min

2010, 21(05):  589-594. 

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The mechanics models formed by packed circular discrete elements and randomly distributed in a specified region were used to investigate the mechanics properties of monocrystalle-silicon, and some different sizes of discrete element model were carried out to study the size effect of mechanics properties. The simulation results suggest that there is no obvious size effect for Poisson's ratio, compressive strength and Young's modulus and fracture toughness. However, the value of flexural strength decreases with the increasing of the model size.The discrete element model of classical continuum fracture mechanics was used to simulate the fracture process of single edge vertical crack plate with finite-width under tensile stress in infinite distance. The simulation results which obtained by changing the initiate crack length of model are just the same with the simulation results of single edge notched bending(SENB) and the experimental values reported in other literatures.

Task Sequencing for Single Product Collaborative Designer Based on Dependency Logic

LIANG Hua-Dong, YANG Yo, LIU Ai-Jun, HONG Jun, WANG Ying-Dong

2010, 21(05):  595-598,623. 

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 Coordination difficulty and single sequencing standard in complicated and crossing collaborative design surroundings claim for the ‘human-task-resource’ effective sequencing. Business rules and task-resource dependence logic based on coordination theory were presented previous to improved tabu algorithm model for task sequencing of single product collaborative designer, which provided effective optimized sequencing and sort the same ‘task-resource’ dependency logic. Case study is demonstrated to illustrate the feasibility and applicability by comparing the outputs of LEKIN simulation tools. 

Calculation of Tube Mechanical Expanding Force with Conical Die and Analysis of Main Influence Factors

CA Jin-Da, CHENG Xi, FU Xiang, GAN Han-Jing

2010, 21(05):  599-602. 

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Mechanical expanding of tube with conical die was investigated, stress state of unit in deformation zone was analyzed, unit model of deformation zone was established, slab method to solve deforming force on metal plastic forming was adopted, according to Mises yield criterion, considering effects of work hardening and bending stress, analytic formula of the mechanical expanding was derived. Moreover, the formula was amended by taking account of effect of fixing-diameter zone.The amended formula indicate that expanding force is related to die semi-cone angle, friction coefficient between die and tube internal surface, original diameter of tube, tube thickness, expanding coefficient and length of die’s fixing-diameter district. The rationality and correctness of expanding force formula were proved by expanding tests.

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LIU Xin, ZHONG Di-Xian, MA Qiang-Xian, YUAN Chao-Long-

2010, 21(05):  603-606. 

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 Based on the thermodynamics research, which was conducted in the temperature range 850～1200℃ and the strain rate 0.01～1s-1, the flow stress curves of low-pressure rotor steel 30Cr2Ni4MoV under the common production conditions of heavy forging was investigated. Then the critical conditions of dynamic recrystallization and the microstructure were studied, and the dynamic recrystallization model of 30Cr2Ni4MoV was established, from which the optimized range of forging parameters was suggested with the order of refining the grain by dynamic recrystallization.

 

Post-buckling Test and Numerical Analysis of Multi-spar Wing Box

LIU Hua-Feng, YUE Zhu-Feng

2010, 21(05):  607-610. 

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The bending static experiments and FEM were used to study the post-buckling performance of a composite thick-skin multi-spar wing box. The well agreements of the load-displacement curves between experiment and FEM show the FEM modeling is credible. Based on this FEM model, the post-buckling behaviors of the wing box under two different loads: concentrate and press load, were investigated. The buckling behaviors were determined by tracing the load-deflection curves using non-linear arc-length method. Numerical results present the critical load,buckling deformation behaviors,the stress distribution and the destroy process. 

Strip Layout Design of Progressive Die Based on Fast Numerical Simulation

ZHANG Zhi-Bing, LIU Yu-Qi, DU Ting, HU Heng-Jian

2010, 21(05):  611-614. 

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The strip layout of automotive structural parts in the process design of progressive die is the major difficulty and the bottleneck problem to be solved urgently. However, the strip layout is designed mainly based on experience at present. A strip unfolding method for progressive die stamping parts was developed, which was according to the process features and based on the inverse approach. In the method, the stamping processes, such as connection, blank-holder force and the friction were considered, and the intermediate shapes and the formability can be calculated with high efficiency. The details of the method were illustrated with a complicated stamping part.

Vehicle State Estimation Based on Unscented Kalman Filter Algorithm

DIAO You-Qun, LIN Fen

2010, 21(05):  615-619,629. 

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A critical component of vehicle dynamic control systems is as accurate and real time knowledge of vehicle key states when running on road. UKF algorithm was used in vehicle state estimation. The nonlinear vehicle dynamics system which contained constant noise and nonlinear tire model was established. Several vehicle key states were estimated using UKF with symmetrical sampling strategy and proportional correction. The estimator based on UKF is compared with the estimator based on extended Kalman filter (EKF). The results of virtual experiments based on ADAMS/Car and real vehicle experiments demonstrate that UKF is available in vehicle state estimation. 

Research on Fine-simulation for Auto-door Stiffness Based on Forming

LIU Rui-Jun, HU Beng, ZHANG Jie

2010, 21(05):  620-623. 

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In order to improve CAE simulation precision of auto-door stiffness，a method of fine-simulation for auto-door stiffness was proposed，in which the forming results (thickness，stress，strain) were as initial data before analysis of auto door stiffness. Forming result file(*.nas) of KMAS/one-step had been converted into a file (*.inp) which can be recognized by ABAQUS by means of mesh model converting rules before the file was imported. Simulation results show that the fine-simulation can improve simulation precision for auto-door stiffness, and give a feasible & effective method for panel(s) and structure part(s) to improve simulation precision.

Study on Differential and Independent Steering Performance Simulation for Hydrostatic Drive Tracked Vehicle

YANG Lei, MA Biao, LI He-Yan, SHU Ya

2010, 21(05):  624-629. 

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The steering simulation was conducted by using MATLAB/Simulink on the basis of analyzing the steering process of a hydrostatic drive tracked vehicle. Total power the vehicle consumes, motor load torque and system pressure in in-situ steering are all the maximal in three steering conditions.Independent steering is to be adopted in small radius steering, which can make the driver step accelerator pedal to increase average speed and improve vehicle mobility in the case of completing the steering. Differential steering is to be adopted in modified steering, which provides excellent system dynamic characteristics.