China Mechanical Engineering

Analysis on Stress Distribution and Influencing Factors of Planar Double Enveloping Hourglass Wom Gears

ZHANG Pan-Qin, ZHANG Guang-Hui

2011, 22(10): 1135-1138.

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Based on the elastoplasticity contact finite element theory,

a multi-group static and dynamic contact stress analysis models suitable for the worm gears were established. The influences of the load and parameters on the coefficient of load sharing among teeth and contact stress distribution were studied. The relationship between the number of teeth in the meshing and the maximum coefficient of load sharing among teeth under different loads was calculated.The results indicate:the load distribution tends to be even along with load enlargement; the contact stress distribution along the contact line like “L” or “U”;the influence of parameters on the stress can not be neglected,it is feasible that parameter optimized aimed at stress hypodispersion by contrasting the finite element analysis results.Under 0.05~1.5 times the rated torque, the maximum coefficients of load sharing among the teeth are obtained when the number of meshing teeth is 3,5,7 respectively.

The Development of Transmission Error Dynamic Measurement System Based on Time Grating Displacement Sensors

BANG Dong-Lin-1, 2, ZHENG Yong-1, CHEN Zi-Ran-1, GAO Zhong-Hua-2, ZHENG Fang-Yan-2

2011, 22(10): 1138-1142.

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Optical gratings are applied to traditional transmission error dynamic measurement system as angle detecting sensors, but high-precision optical gratings are expensive and imported restrictedly.In view of this situation, a time grating, the novel displacement sensor of proprietary intellectual property rights, is invented. Absolute displacement signal of time grating is converted into incremental pulse signal with time series models. and the experiment results prove that accuracy of measurement can achieve

0.137% by using sophisticated FMT test transmission error of gear-hobbing machine, so the desired schematic design has been obtained.

Study on Fault Tolerance and Fault Rectification Strategy and Approach for Singularities of a 4-DOF Spatial Parallel Mechanism

CHEN Shi, FAN Shou-Wen

2011, 22(10): 1143-1148.

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Based on singularity classification approach of Gosselin, singularities of type Ⅱ were treated as a kind of mechanical system faults, a fault-tolerance and fault-

rectification strategy framework for eliminating singularities was presented based on actuation redundancy herein. Basic idea and implementation process of this framework

were expatiated, the essence of singularity occurring and singularity being removed

were interpreted by solutions of linear equations and matrix condition number. Degree of singularity fault-tolerance was defined as an index for describing the performance of singularities being eliminated. Based on this index, an optimization algorithm was proposed

to determine optimal structural parameters for the redundant actuation, which enabled parallel manipulators to possess maximum singularity fault-tolerance ability. A typical singularity loci for 2RPS&2TPS parallel mechanism was obtained, three fault-tolerance and fault-rectification strategies were presented and compared in details. Simulation researches for above three fault-tolerance and fault-rectification strategies were conducted.Simulation results show that the fault-tolerance and fault-rectification strategy based on degree of singularity fault-tolerance can eliminate side effect of singularities in parallel mechanisms effectively.

Gaining of Geometric Characteristics for Incisor Teeth and Its Analysis of Biologic Mechanics Property

XIE Feng, CHEN Wei-Lei, ZHANG Ye, LIU Guo-Lin

2011, 22(10): 1149-1153.

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The paper was based on the bionic research of the incisor teeth of beaver.The point cloud of geometric shape and three dimentional curved surface model for the incisor teeth was obtained by reverse engineering(RE) technology.Its fittng equations were also gained by picking up the characteristic line of the built surfaces and the points’ coordinates.And then the analysis of its characteristics was carried out.All of those will supply the foundation of bionic design for the

optimization of the geometric shape and mechanics property of cutting tools.

Optimization Design of Cushion Instrument of Honeycomb Structure

YIN Han-Feng-1, 2, WEN Gui-Lin-1, 2, MA Chuan-Shuai-1, 2, HAN Hong-Li-1, 2

2011, 22(10): 1153-1158.

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After simplifying the crushing strain-stress curve of honeycomb structure under axial loading,an ideal crushing strain-stress curve was obtained. Based on the ideal crushing strain-stress curve, the energy absorbed by the cushion instrument of honeycomb structure and the peak crushing force were calculated. In order to design a cushion instrument of honeycomb structure that has the biggest energy absorption capacity per unit mass and has the minimum cushion overload,a cell wall thickness and width of the honeycomb structure were optimized by using multi-objective optimization method. According to the optimization results, the minimum axial length of the honeycomb structure can be calculated. Then, the honeycomb cushion instrument installed in the four legged lander was optimized using this method. The optimization results were verified by employing the multi-body dynamics model established in Adams

software.The simulation results indicate that this optimization method can direct the design of the landing instrument very well. This method can reduce the times and the cost of

the tests,and meets the cushion demands of different overloads. 

Design of Timing Chain Parameters Based on Chain Transmission Meshing Characteristics

LI Bao-Lin, TANG Li, CHU Xiao-Liang, FAN Shuai

2011, 22(10): 1159-1164.

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The chain transmission characteristics in different initial phase angles of chain were analyzed from the perspective of geometry and the principles of virtual displacement.In addition,the effects of driven wheel angular velocity and angular inequality coefficient were analyzed with different central distances of two sprockets.

The influences of initial phase angle geometry characteristic parameters of the chain transmission on driven wheel angular velocity and angular inequality coefficient degree were analyzed and the fluctuation trend of driven wheel angular velocity was found out at the same time.It is found out when the other parameters are certain,how the damper of timing chain system guides the plate pressure degree and radius curvature in order to obtain the minimum angular velocity changes and angular inequality coefficient of driven wheel. Hence the assistant formula and the validation constraint equation were provided and the ideas, as well as, the methods for the design of engine timing chain system were put forward.

Model Identification Based on Multi-objective Optimization for AGV Driving Systems

WU Xing, LOU Pei-Huang, TANG Dui-Bing

2011, 22(10): 1164-1168.

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A novel model identification approach based on least square method and multi-objective genetic algorithm was presented for the driving system of AGV. The model identified by least square method was adopted by multi-objective genetic algorithm as an evolution tutor who selected these individuals having a balance among a set of objective performances as elitists. Lossless finite precision method was used to keep the population diversity, and a multi-objective combined function was designed for a quick search for Pareto optimal solutions. The model identification experiments of AGV driving system demonstrate that the response curve of the model identified by the novel approach is much consistent with the object response curve both in amplitude and phase, which will provide a precise system model for AGV servo control system design.

Force and Deformation Analyses for Flexspline of an Electromechanical Integrated Electromagnetic Harmonic Friction Drive

LIN Yu-Bei-1, HU Li-Zhong-1, LIANG Yong-Li-1, 2

2011, 22(10): 1169-1172.

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In view of the phenomenon that an electromagnetic harmonic friction driving flexspline will deform in a magnetic field, this deformation will change the airgap at any moment,a concept of airgap function was introduced.And based on thin-shelled elastic deformation theory, simplifying the driven flexspline to a column shell，a model was built and used to analyse the static force of flexspline affected by electromagnetism.Due to this method has considered flux density change caused by flexspline formation, it can precisely describe the characteristics of the radial electromagnetic force,the force and deformation rule of flexspline.It provides a more reliable theoretical basis for harmonic electromagnetic motor structure design and strength check.

Reactive Scheduling for Multiple Mould and Die Projects Based on Improved Multi-objective Particle Swarm Optimization

ZHANG Sha-Qing, CHEN Xin-Du, CHEN Qiang-Xin, CHEN Xin

2011, 22(10): 1173-1179.

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This paper proposed a reactive scheduling algorithm for multiple mould and die projects to deal with multiple stochastic disruptions during projects execution including uncertain renewable resources infeasibilities due to breakdowns, multiple tasks taking longer time than planning and random arrivals of new projects. Firstly, uncertain renewable resources availabilities were analyzed with the theory of birthdead process, and an initial schedule was constructed by using topological sorting method based on priority rules. Then, a multi-objective reactive scheduling model with the optimization objects of minimizing the weighted sum duration of projects and the disruptions cost, defined as the weighted sum of the deviations between the executing schedule before reactive scheduling and a new schedule after reactive scheduling was built, and an improved multi-objective particle swarm optimization was proposed to solve it. Finally, the feasibility and reliability of the reactive scheduling algorithm were analyzed by simulations.

Factory Planning and Workshop Layout Based on Interactive Virtual Environment

DAI Da-Meng

2011, 22(10): 1180-1184.

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A new approach to factory planning was proposed herein.An equipment resource database was built,which contained physical models, logical models and motion models, thus enabled to create virtual factories and workshops quickly using virtual reality techniques. We also applied genetic algorithm to optimize the workshop layouts in the creation of the virtual workshops.Furthermore, we developed a prototype system based on a 3D virtual environment to support interactive simulation and design.The design platform proposed is highly efficient and cheap to be implemented,thus it is significant in promoting the rationality of factory planning. 

Research on Knowledge Description Method of Knowledge Template Five Factors Based on Pattern Language

GUAN Qing-Gui, YAN Guo-Fu, HU Xiao-Bing, YIN Xiang-Yun

2011, 22(10): 1185-1188.

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Faced on mass design knowledge which hides in a product design example,how to describe effectively all kinds of design process knowledge under the web-based product design,establishing a support knowledge base for intelligence design,discovering and accumulating all sorts of knowledge in design process,providing the method for knowledge reuse,were the important technology problems for constructing and realizing in intelligence design.A method of applying pattern language to describe these knowledge was put forwarded.A die design resource data and knowledge base system was developed successfully for verification of the architecture, key technologies and implement methods.

Application of Human Visual Attention Mechanism in Surface Defect Inspection of Steel Strip

CONG Jia-Hui, YA Yun-Hui

2011, 22(10): 1189-1192,1221.

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It is difficult to judge the defects if only based on gray information. In response to the low contrast and small defects, a novel algorithm based on human visual attention mechanism was proposed. According to biological structure and function of human visual system, a detection model was built combining multiple scales and frequencies of Gabor filter with multichannel and multifreqency of human visual system.

The experimental results show that this method is effective to detect the surface defects and establish the coordinate position of defect region. The inspection speed is fast,which can satisfy the real-time detection system’s demands. 

Blind Signal Processing Based on Negentropy for Rotating Machines

MOU Wen-Feng, CHEN Xiao-Hu, SU Xun-Jia, TAO Chun-Jiang, WANG Xu-Beng

2011, 22(10): 1193-1197.

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In blind signal processing of mechanical equipment,it is common that mechanical source number is more than that of multi-channel observation signals. This was called underdetermined blind signal processing. Then negentropy and empirical mode decomposition(EMD) was introduced into feature abstraction of mechanical equipment to deal with their single channel blind signal processing.This algorithm was composed of three steps. Step 1 was to decompose single channel mechanical observation signals with empirical mode decomposition and get intrinsic mode functions(IMFs).Step 2 was to compute negentropy values of IMFs and form a negentropy eigenvector according to IMFs sequence. Step 3 was to recognize different working patterns and diagnose different faults with LS-SVM. Its applications in blind signal processing of hydraulic gear pumps show that, its fault diagnosis rate is up to 93% on the whole. This indicates that this algorithm can be applied to mechanical blind signal processing.

Contact Reliability Assessment of Aerospace Electrical Connector Based on Step-up-stress Accelerated Degradation Testing

BO Jun-1, LIU Gong-Jie-1, CHEN Wen-Hua-1, 2, JIAN Ping-1, LIU Juan-2

2011, 22(10): 1197-1200.

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In order to evaluate the contact reliability for aerospace electrical connector with high reliability and long life quickly,this paper analyzed the failure mechanism of aerospace electrical connector,then established the corresponding accelerated degradation model.On this basis,a step-up-stress accelerated degradation reliability

assessment algorithm based on pseudo-failure lifetime was proposed.Finally,the step-up-stress accelerated degradation testing for an aerospace electrical connector was completed.

The exprimental data shows that this method to achieve the reliability assessment is compared with the accelerated life test,step-up-stress accelerated degradation testing can decrease testing time.

Networked Collaborative Development Mode and Support Platform Based on Life Cycle of Art Ceramic Products

DAO Xue-Fei, CAO Hua-Jun, CHEN Yong-Feng, LIU Fei

2011, 22(10): 1201-1205.

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Considerting the current challenge of globalization of markets,individual requirements of customers and sustainable development faced by China’s ceramic industry, in view of the cureent problem faced by the conventional development process of art ceramics,a concept of networked collaborative development mode was proposed based on the lifecycle. The operation mode of collaberative development system

was introduced. On the basis of characteristics of product development of art ceramics, the networked collaborative development process of art ceramics and the architecture of networked collaborative development platform for art ceramics was established. The support system, key technologies and ultimate goal to implement networked collaborative development were elaborated. Moreover,a support platform for collaberative development of art ceramics was developed. Finally, the application of this support paltform was demostrated by a specific case study.

Method of Design Knowledge Acquisition Based on Co-evolution Model of Problem & Solution

LIU Zheng-1, LU Na-2

2011, 22(10): 1207-1213.

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In the industrial design areas,a method for information translation based on the co-evolution model of problem & solution was put forward to acquire the dynamic knowledge from design process.The basic concepts of industrial design knowledge were discussed;the characteristics in this area were pointed out,which had a great deal of tacit knowledge and expanding spaces of innovation knowledge.The information of design process was collected by the oral report from the cases of concept design.After the knowledge resource was identified,the high value information was defined by the existing system of concepts.Facing the ill-defined design problems,a co-evolution model of problem & solution was formed to describe the innovation process by distinguishing the problem

space and solution space.At the same time,the general frameworks of ontology for design requirements and solutions were also built up.The important nodes were determined

by the above model.And the industrial design knowledge of the nodes was captured by adopting the relevant ontology,and signing the relationships among the ontologies.

The format of output was of level structure of frameworks.In the end,the system of knowledge acquisition & management was established to test the above methods by the cases of

flash disc form design knowledge acquisition & translation.

Study on Mechanical Behavior of Composites Stitched Foam Sandwich Panels under Flatwise Compression and Shear

LIU Hua-Feng-1, DIAO Kai-Hui-2, WANG Pei-Yan-1, YUE Zhu-Feng-１

2011, 22(10): 1213-1215.

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Experiments on three kinds of composite foam core sandwich structures under flatwise compression and shear were present herein.Unstitch foam,lock-stitch

foam and Tufting stitch foam sandwich structures were produced using the same face

materials in order to study the stitch methods how to influence the mechanical property and failure modes.The experimental results show the significant increase in the strength and modulus of flatwise compression and shear of the stitched foam sandwich structures.Different stitch methods brought the different extent increases of the stitched structures.Tufting stitch is better than lock-stitch in the increasing of the strength and modulus.The results can be used in structural design and theoretical analysis.

Study on Dynamic Characteristics of Deep-sea Fluid Control System Based on Power Bond Graph

TUN Fu-Chao-1, CHEN Ying-2, JIN Bei-2, YANG Can-Jun-2

2011, 22(10): 1216-1221.

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A kind of fluid control system was designed using pressure compensation method for in-situ pH exploration of deep-sea hydrothermal fluid. In order to disclose dynamic characteristics of the fluid control system adopted pressure compensation method, power bond graphs were drawn by means of bond graph theory, and on this basis, mathematic models of the fluid control system were built, thus, the foundation for simulation was laid. The fluid control system was simulated by MATLAB/Simulink,and the simulation results show that dynamic process of the fluid control system is generally smooth when sucking in atmospheric pressure; pressure occurs sudden change when sucking in high pressure; pressure occurs slight fluctuation when draining in atmospheric pressure and high pressure. All of these explains that the system will occur sudden pressure changes and vibrations in high pressure environment in despite of the fluid control system can apply in deep-sea high pressure environment by means of pressure compensation method. Therefore,the solutions of avoiding open and close frequently in high pressure environment were put forward. The sea trial experiments indicate the fluid control system can work normally in high pressure environment on the seafloor. 

A Cellular Automaton Model for Friction Process Dynamic Characteristics of Gland Self-lubricating Composite

YAN Song-Shan, LIU Zuo-Min

2011, 22(10): 1222-1225,1231.

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The dynamic evolution mechanism on a friction surface of high temperature gland self-lubricating composite was analyzed based on the micro-structure characteristics of the materials and its tribological experimental results in the pin-disk test. A cellular automaton model to describe the dynamic characteristics of the friction process was developed and used to study the friction coefficient and the topography as well the lubricants distribution on the worn surface in the sliding. The agreement between the simulation and experimental results show the model is available and can be used to optimal design of the materials. 

Spot Weld Simulation Using Solid Element Assemblies Based on Crashworthiness of Automotives

XIE Bin, CHENG Ai-Guo, CHEN Chao, DONG Li-Jiang

2011, 22(10): 1226-1231.

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Several commonly used methods of spot weld simulation were summarized and a new solid spot weld elements model was proposed, according to the efficiency and simulation accuracy of the spot weld elements in vehicle crash model. Spot weld elements using solid element assemblies and beam elements were built in detail and their accuracy was systematically compared, based on the crash tests of thin-walled rail. And the most accurate results were gained by using HEX8 elements. The whole car simulation analysis of crashworthiness using spot weld failure parameters obtained by specimen test and the new HEX 8 elements model gave more accurate results. The vehicle tests demonstrated that this solid elements assemblies spot weld model has higher precision and stronger project practicability.

Investigation on Forming Limit Diagram Characteristics for Tailor Welded Blanks

HU Qiao-Qing-1, 2, NI Feng-2, 3, LIN Jian-Beng-1

2011, 22(10): 1232-1235.

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Through the investigation of FLD characteristics for TWB under

different conditions, the cracking in TWB forming process were explained by that the weak-side base material was up to its forming limit in advance. The position of FLD critical

curve was determined only by material property in cracking regions(material performance and thickness), and different factors mainly affect the range of limit forming state when cracking occurs.

Analysis of Specific Energy Consumption and Ratio Optimization of BEV Based on Running Schedule

ZHOU Bing, JIANG Qing-Hua, YANG Yi, WANG Ji-Sheng

2011, 22(10): 1236-1241.

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Through the analysis of running schedule of Changsha,according to the automobile running equation,the minimal energy under the sampling points were analyzed, and the recycle of braking energy of motor was analyzed,the expression of specific energy consumption was derived.The objective function of optimization was established with the specific energy consumption under the loop and main-road running cycle and the dynamic factor,the boundary constraints of ratio optimization were established with the maximum speed and peak torque of the motor and traction.In order to assure the dynamic performance of the designed car under the lower state of charge of the battery,the boundary constraints were introduced in the optimization.A particle swarm optimization based on the simulated annealing was used in the optimization,the weighting coefficient was also introduced in the optimization.The optimization results

increase the dynamic factor and reduce the specific energy of the designed car under a group of weighting coefficients.

Simulation and Experiment on Heat Balance Process in Lubrication System of a Heavy-duty Automobile Transmission

RUAN De-Fang-1, LIU Bei-1, CHEN Zhi-Di-2, ZHANG Xu-Yong-2, ZHANG Yong-2

2011, 22(10): 1242-1246.

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On the basis of analyses on the power losses and the heat transfer in lubrication system of a heavy-duty automobile transmission,a heat balance simulation model for the lubrication system was established with the software AMEsim and then the simulations were completed under several operation conditions.In order to verify the simulation model, an experiment was conducted at no-load and in direct drive.

The results show that the balance temperature at high-speed and light-load or high-speed and high-load is much lower than the highest temperature at which the transmission can operate normally; the temperature of the lubricating oil goes up very quickly and reaches the limiting value in about 30 minutes at high load and in first gear; the simulation results of the balance temperature are coincide well with the experimental ones at no-load and in direct drive, and the relative error is less than 2%.

Development Trends of High-end NC Equipment

WANG Ta-Yong-1, JIAO Zhi-Feng-1, HAN Zhi-Guo-2, DONG Jing-Chuan-1, QI Jin-Zhang-1

2011, 22(10): 1247-1252,1259.

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This paper introduced the key technology’s development trend of a modern high grade NC equipment. Firstly, according with the development of the key functional units in a machine tool,the paper discussed the mainstream development of the NC machine tool in the aspect of high speed,high precision,high efficiency and high reliability, and further pointed out the reliability of machine tool was the key factor that affected the market competitiveness of China machine tool companies. Secondly, with the continuous development of high-grade NC system in intelligence, open, networking and other aspects, the future development direction and important impact on the CNC technology of the latest digital control technology were described and the latest research results both at home and abroad were also introduced. Finally, combining with the current development situation of domestic NC industry, the relevant individual recommendations about the development of high-grade digital equipment were proposed.

Research on Key Technologies of Self-adaptive Immune Monitoring of Bio-inspired Manufacturing System

TANG Dui-Bing, ZHENG Kun, GU Wen-Bin, SHANG Ding-Shan

2011, 22(10): 1253-1259.

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Combining the control model of bio-inspired manufacturing system(BIMS) with the algorithms of artificial immune system(AIS), this paper established an immune monitoring system(IMS). Besides, this paper proposed the strategies of health assessment of manufacturing system with the help of analytic hierarchy

process(AHP) model.Finally,a simulation experiment was carried out based on the IMS

proposed herein, and the results show that the system has a good adaptability for the changes of internal and external environments of manufacturing system.It can also give a reasonable evaluation of the manufacturing system which can match the actual state very well. Therefore, the proposed IMS has good effectiveness and reliability.

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