bluuebunny/crossref_metadata_2025 huggingface dataset:
Precision Displacement Measurement of Single Lens Reflex Digital Camera
Authors: Yi Xue Feng , Long Si Chun
Published: September 2011

When the stripes are photographed by digital cameras,Moiré fringes will be in the photograph. With the displacement amplification of Moiré fringes, tiny movement of stripes can be calculated precisely. We expounded its calculating methods in this paper. Experimental data show that high precision can be guaranteed.It is well known that the high rate zoom characteristic of moire fringe technique can be well used in precise measurement of digital Camera’s displacement, and besides, widely used in machining, laboratory and photo-electricity equipment. With the development and popularization of digital cameras, especially the great advancement in image sensor’s performance, it now becomes possible to accurately measure the displacement from far away by taking into account the sensor’s moire effect.
Data Registration Method Based on Three Dimensional Target
Authors: Lou Xiao Ping , Lv Nai Guang , Sun Peng , Lin Yi Min
Published: September 2011

Data registration method using special three dimensional target to track the structured light measurement system is discussed. Optical scanning device, tracking target and stereo vision system are integrated together to fulfill profile inspection of large-scale free-form surface objects without extra mark points. System architecture and processing steps are introduced and layout optimization methods of three dimensional target are illustrated. Experimental results are showed to evaluate the validity of the registration method and suggests are given to improve the accuracy of the system.
Application of Autoregressive Distributed Lag (ADL) Model to Thermal Error Modeling on NC Machine Tools
Authors: Miao En Ming , Wang Xin , Fei Ye Tai , Yan Yan
Published: September 2011

Thermal error modeling method is an important field of thermal error compensation on NC machine tools, it is also a key for improving the machining accuracy of machine tools. The accuracy of the model directly affects the quality of thermal error compensation. On the basis of multiple linear regression (MLR) model, this paper proposes an autoregressive distributed lag (ADL) model of thermal error and establishes an accurate ADL model by stepwise regression analysis. The ADL model of thermal error is established with measured data, it proved the ADL model is available and has a high accuracy on predicting thermal error by comparing with MLR models.
Slider Curvature Control through Dicing Process
Authors: Srisang Chirawat , Siangchaew Krisda , Kaewkhao Jakrapong , Pokaipisit Artorn , Limsuwan Pichet
Published: September 2011

In the manufacturing of slider, the final step is a dicing process of the rowbars into individual slider. However, in all slider separation processes seem to affect the curvature of the slider air bearing surface (ABS). As a result, the change in ABS crown and camber which can significantly affect the fly height of the slider. This paper investigates the influence of three types of dicing process, with the same feed rate and cutting speed, on the ABS curvature.
A Second Order Approximation Technique for Robust Shape Optimization
Authors: Sichau Adrian , Ulbrich Stefan
Published: September 2011

We present a second order approximation for the robust counterpart of general uncertain nonlinear programs with state equation given by a partial di erential equation.We show how the approximated worst-case functions, which are the essential part of the approximated robust counterpart, can be formulated as trust-region problems that can be solved effciently using adjoint techniques. Further, we describe how the gradients of the worst-case functions can be computed analytically combining a sensitivity and an adjoint approach. This methodis applied to shape optimization in structural mechanics in order to obtain optimal solutions that are robust with respect to uncertainty in acting forces. Numerical results are presented.
Approach for a Consistent Description of Uncertainty in Process Chains of Load Carrying Mechanical Systems
Authors: Eifler Tobias , Enss Georg C. , Haydn Michael , Mosch Lucia , Platz Roland , Hanselka Holger
Published: September 2011

Uncertainty in load carrying systems e.g. may result from geometric and material deviations in production and assembly of its parts. In usage, this uncertainty may lead to not completely known loads and strength which may lead to severe failure of parts or the entire system. Therefore, an analysis of uncertainty is recommended. In this paper, uncertainty is assumed to occur in processes and an approach is presented to describe uncertainty consistently within processes and process chains. This description is then applied to an example which considers uncertainty in the production and assembly processes of a simple tripod system and its effect on the resulting load distribution in its legs. The consistent description allows the detection of uncertainties and, furthermore, to display uncertainty propagation in process chains for load carrying systems.
Evaluation and Control of Uncertainty in Using an Active Column System
Authors: Koenen Jan F. , Enss Georg C. , Ondoua Serge , Platz Roland , Hanselka Holger
Published: September 2011

Uncertainty in usage of load-carrying systems mainly results from not fully knownloads and strength. This article discusses basic approaches to control uncertainty in usage ofload-carrying systems by passive and active means. An active low damped column system critical to buckling is presented in which a slender column can be stabilised actively by piezo stackactuators at one of its ends only. Uncertainty may be controlled in the active column systemby temporarily enhancing the bearable axial load theoretically up to three times compared to the passive column system in case of critical loading. However, in the implementation of theseapproaches, system-speci c uncertainty may also occur. In numerical examinations it is shown, that small deviations in measured axial loading may increase the active force signi cantly to achieve stabilisation. The increase of applied active force might affect lifetime of the piezo stackactuators and thus the stabilising capability of the active column system.
Behaviour Prediction Framework in System Architecture Development
Authors: Osman Krešimir , Štorga Mario , Stanković Tino , Marjanović Dorian
Published: September 2011

This paper proposes a Behaviour Prediction Framework with an objective to help designers tackling the problem of uncertainty emerging from system architecture and the effects of the uncertain operating conditions. The proposed framework combines structural and dynamic system model. The Design Structure Matrix is applied to model structural arrangements and dependencies between the subsystems. The Model Predictive Control is applied to model the system in discrete and continuous dynamic domains. As the result of the proposed framework, stability analysis of subsystems in interaction become possible and feedback on system architecture could be provided. To test validity of the proposed approach, the test case involving climate chamber with heat regeneration is presented.
Time-Dependent Fuzzy Stochastic Reliability Analysis of Structures
Authors: Graf Wolfgang , Sickert Jan Uwe
Published: September 2011

The paper reviews the development of reliability assessment in structural analysis under consideration of the non-traditional uncertainty model fuzzy randomness. Starting froma discussion of sources of variability and imprecision, uncertainty models are introduced. On this basis, numerical approaches are displayed for uncertain structural analysis and reliability assessment. Thereby, variations in time are considered which results in a time-dependent reliability measure. Capacity and applicability of the approaches are demonstrated by means of an example.
The Compare and Analysis to the Hollow or Solid Circle Cross Section Shafts Being Twisted
Authors: Zhang Yan
Published: September 2011

From the angle of saving material, the author make the related computing, as well as compare and analysis to the biggest torsion shearing stress of the hollow or solid circle cross section shaft. Simultaneously it is elaborated, when the most torsion shearing stress of the hollow circular cross-section axis is smaller than the solid circular cross-section axis, the rule of economizing material and the change of the appearance size. Elaborate further, the related reasonable sizes are given, in order to have the prior adoptions during the design or transform. For example, the ratio of the hollow circle cross section shaft external diameter and inner diameter is two in the engineering, and the economical material is in 15%-inside 25% ranges.
Influence of Self-Vibration Characteristics of Pump Station Considering Liquid-Solid Coupling
Authors: Zheng Ke Hong , Li Tong Chun
Published: September 2011

Considering the contacts between solid and fluid are subjected to dynamic lodes, the influence of vibration characteristic of structure which is coupled with solid and fluid are applied to calculation. In this paper, the calculation formula of structure vibration between solid mass and fluid is derived and the finite element method (FEM) is adopted for discrete of pump station structure and fluid, considering the effect of fluid flow to solid structure, the natural frequency of pump station is acquired. The result shows the method is correct and reasonable.
An Extraction Method for Live-Load Effect of Bridge Based on EEMD
Authors: Wu Jun , Chen Wei Min
Published: September 2011

Bridge plays an important role in modern transportation. Once it is damaged, there will be great loss. So assessment of bridge state has become more and more important in modern society. Ambient around bridge always are very complex and bridge is affected by many factors. So in all response of bridge, noise and useful signals mixed together. The noise generally includes temperature effect, wind load effect, live-load effect, and so on. In order to get the useful signals we must separate the live-load effect from the total effect by using multi-scale analysis firstly. EMD brought a new method for multi-scale analysis and it is superior to wavelet to some extent. But it has some shortcomings also. In order to improve the performance of the EMD further, EEMD is introduced to extract live-load effect of bridge. The practical and simulation results verified the feasibility of the new method based on EEMD and the results is much better than those based on wavelet.
Seismic Intervention and Dynamic Testing of an Arch Bridge
Authors: Islami Kleidi , Tecchio Giovanni , Modena Claudio
Published: September 2011

This work presents the dynamic tests on a retrofitted masonry arch bridge. The Gresal Bridge, located in the North-East of Italy, was highly exposed to seismic hazard, due to the slenderness of its high piers. A retrofit intervention has been carried out, and a new rc slab has been built under the pavement, anchored to the piers with high strength vertical ties and restrained at the abutments, to create a new resistance arrangement withstanding inertial forces. The dynamic behaviour has been initially assessed with numerical models comparing the response of the bridge before and after the repair, and has subsequently been tested by the Output-Only technique to detect the variation of the modal response induced by the strengthening intervention. The dynamic tests have shown the structure to be more rigid than expected and, after calibration, a good agreement to exist between the numerical frequencies and the experimental records captured on the retrofitted bridge.
Stability Analysis for the Milling of Thin-Walled Plates
Authors: Wu Kai , Jiang Ai Jun , Yang Kai
Published: September 2011

In order to restrain the regenerative chatter and improve the processing efficiency of thin-walled parts, stability analysis for the milling of thin-walled parts should be the critical element in the whole process of analysis for thin-walled parts. This paper mainly introduces the stability analysis for the milling of thin-walled plates. The two-dimensional stability lobes of milling of plate plotted, the effect of different modal parameters on the stability of milling of plate is investigated. It is shown that single mode will reduce the range of stability zone of main mode if the stability lobes of single mode are intersectant with that of main mode and the range of stability zone will be larger and the stability lobes will be regular on condition that the mode is symmetrical.
The Numerical Simulations of Forces Acting on TBM Disc Cutters with the Consideration of Confining Pressure and Damage in Rocks
Authors: Li Hui Yun , Shi Guang Yu
Published: September 2011

This paper gives a brief explanation of the failure mechanism of rock fragmentation in rock cutting. The JOHNSON_HOLMGIST_CONCRETE is selected as the rock material model in numerical simulation with confining pressure and damage influence introduced. We use the non-linear dynamic finite element software LS/DYNA to simulate the dynamic process of cutting rock. The cutting forces acting on disc cutter are computed. The relationship between cutting forces and penetration depth, confining pressure and damage parameters are obtained. The results show that, the cutting forces increase with the penetration depth. They are larger in equal confining pressure than unequal condition. The forces are amplified with the damage parameters increasing. The conclusion provides a reference for the prediction of the cutting forces.
Study on Reasonable Fastener Stiffness of Ballastless Turnout's Vibration Decrease and Noise Reduction of 350 km/h Passenger Dedicated Line
Authors: Xu Jing Mang , Ping Wang , Xu Da Zhen
Published: September 2011

With the large-scale construction of passenger dedicated line, more and more ballastless turnouts were laid as the important infrastructure of passenger dedicated line, and the fastener stiffness of it influenced the vibration and noise of the track. Using the vehicle-turnout coupling dynamic analysis created the method for determining the reasonable fastener stiffness of ballastless track turnout to analyse mutative fastener stiffness's impact on the vibration and noise. Then from three parts of the excitation of wheel-rail roughness, the sound radiation efficiency and the calculation of wheel-rail radiated noise, the noise prediction method for ballastless turnout was stated. Using the above methods, The reasonable fastener stiffness of ballastless turnout can be obtained. The results showed that the stiffness of 25 kN/mm to the fastener of ballastless turnout was reasonable for vibration decrease and noise reduction.
Stress Intensity Analysis of GFRP Bridge Deck Structure
Authors: Zhu Kun Ning , Wan Shui
Published: September 2011

The finite element model is built by ANSYS, and the distribution of stress is studied. The stress intensity of each layer is computed by Tsai-Wu stress intensity standard. The value computed by Tsai-Wu stress intensity standard under given loads are smaller than 1, and the GFRP bridge deck is in a safe state. The first ply failure is also studied, and the result shows that the first ply failure value is determined by the webs when the webs are very thin. Other circumstances the value is determined by the size of the top and bottom plate. The material utilization is the highest when the thickness of the bottom is equal to the whole webs and a little thinner than the top plate.
Numerical Investigation and Structural Analysis on the Springing Joint of a Steel Truss Arch Bridge
Authors: Wu Chong , Yang Guo Tao , He Zu Lin , He De Fu , Su Qing Tian
Published: September 2011

Arch springing is an important critical joint in a steel truss arch bridge, and it has a great influence on the mechanical behavior of the global structure. The adoption of a reasonable structure of the springing joint is of important significance in the design of an arch bridge. In this paper, with regard to the structure of Xinshiji Bridge, two types of arch springing were put forward. In Scheme-1, the lower chords of steel truss arch ribs are connected to the concrete piers with shear studs on the ribs and cap plates welded on the ribs at the top of concrete piers., while Scheme-2 is a integrated spring joint with a base plate on the bottom of the steel arch ribs and with reinforcing bars through the holes on the joints steel arch ribs. 3D finite element models of the two types of springing joint were established and the relative slips between the concrete and steel were taken into account in the analyses. The mechanical behavior of the concrete and the steel structure of the joints under applied loads was investigated and the analysis result showed that Scheme-2 is a relative better structure of springing joint, with less principle tensile stress in concrete and less Mises stress in steel plates.
Stochastic Stability of Mathieu-Van Der Pol System with Delayed Feedback Control
Authors: Feng Chang Shui , Chen Shuang Lin
Published: September 2011

The asymptotic Lyapunov stability with probability one of Mathieu-Van der Pol system with time-delayed feedback control under wide-band noise parametric excitation is studied. First, the time-delayed feedback control force is expressed approximately in terms of the system state variables without time delay. Then, the averaged Itô stochastic differential equations for the system are derived by using the stochastic averaging method and the expression for the Lyapunov exponent of the linearized averaged Itô equations is derived. It is inferred that the Lyapunov exponent so obtained is the first approximation of the largest Lyapunov exponent of the original system, and the asymptotic Lyapunov stability with probability one of the original system can be determined approximately by using the Lyapunov exponent. Finally, the effects of time delay in feedback control on the Lyapunov exponent and the stability of the system are analyzed. The theoretical results are well verified through digital simulation.
Structural Reliability Analysis of a Steel Truss Bridge Based on the Monitoring Data
Authors: Jiang Xiang Lin , Zeng Guo Liang , Tan Jin Hua
Published: September 2011

The stress histories of monitored members are used to get stress spectrums for a steel truss bridge through rain-flow algorithm, then the distribution functions and their characteristic parameters of stress spectrums are obtained to simulate the stress spectrums numerically through Monte Carlo methold, which used to evaluate the structural fatiguelife based on stress-probabilistic model and accumulated damage theory, and the fatiguelife and its hot spots of whole bridge are acquired , which is important for the strategy of bridge management.
Study on Relation Between D-P and C-M Failure Criterion and Rock Fracture Toughness
Authors: Zheng Yan
Published: September 2011

First describe the selecting rule of the C-M and D-P failure criterion and the rule and the relations of the D-P criterion parameter with the rock mass fracture toughness; then through overlapped stresses in the end region of crackle, the total stresses about end region of tensile and sheared crackle can be obtained. The results are introduced into D-P failure criterion and C-M failure criterion, the relation between criterion D-P failure criterion, and rock fracture toughness KⅠc,KⅡc. can be derived. Compared with the results of experiments, which proved the validity of the derivation.Through overlapped stresses in the end region of crackle, the total stresses about end region of tensile and sheared crackle can be obtained. The results are introduced into D-P failure criterion and C-M failure, the relation between criterion D-P failure criterion, and rock fracture toughness KⅠc, KⅡc. can be derived. Compared with the results of experiments, which proved the validity of the derivation.
The Major Problems and Countermeasures on the Shield Machine Tunneling in the Hard Rock Stratum
Authors: Hong Kai Rong , Yang Ren Hua
Published: September 2011

With the rapid development of urban construction, the shield construction technology has been greatly developed. Shield tunneling method generally adapts to relatively uniform soil, soft rock and sand rock strata, and the shield tunnel construction has been more mature for the homogeneous strata. However, for the soft and hard interbedded strata, how to solve the problems of breaking the hard rock, increasing the tunneling efficiency and reducing the construction costs, are difficult problems in the shield tunnel construction. In this paper, based on a great deal of theoretical analyses and engineering practices, the effective methods of improving the efficiency of tunneling, reducing cutter wearing and decreasing the construction costs in the process of the shield tunneling construction in hard rock and gravel layer are proposed.
Test on Meso-Damage Data of Marble under Dynamic Load
Authors: Ni Xiao Hui , Li Xiao Juan
Published: September 2011

The failure damage of granite under axial load are caused by the propagation and coalescent of cracks at mesoscale, so it is of important theoretical value and practical significance to to understand the mechnical properties of rock by experimental research on meso damage of granite. The microfracturing process of the pre-crack marble sample on surrounding rock in immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression is recorded by using the testing scheme. According to stereology theory, the propagation and coalescent of cracks at meso-scale are quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, is obtained from binary images after segmentation. The results show that the new meso-mechanical testing scheme on rock meso-damage could be used to quantitatively analyzed from the geometric information of rock microcracks.
NDT Using Transmission Line Model to Identify the Defects in Pile Shaft
Authors: Ragab Fawzy M.
Published: September 2011

The behavior of piles having a single defect which may be necking, bulging or of inferior concrete is simulated by an electrical model representing an electrical transmission line. The model successively simulated defective piles embedded in homogeneous soil. Through the interpretation of response curves supported by appropriate mathematical treatment it was possible to study piles having a single defect .The type of defect can be identified from the response curve by comparing the pile head stiffness of suspect pile with that of a similar but sound pile in the same site. The location of the defect can be determined by measuring the interval between resonating peaks at higher frequencies. For the same defect location along the shaft of piles in a given site, it can be differentiated between resonating large peaks for piles with bulging and necking.,The behavior of piles having a single defect which may be necking, bulging or of inferior concrete is simulated by an electrical model representing an electrical transmission line. The model successively simulated defective piles embedded in homogeneous soil. Through the interpretation of response curves supported by appropriate mathematical treatment it was possible to study piles having a single defect .The type of defect can be identified from the response curve by comparing the pile head stiffness of suspect pile with that of a similar but sound pile in the same site. The location of the defect can be determined by measuring the interval between resonating peaks at higher frequencies. For the same defect location along the shaft of piles in a given site, it can be differentiated between resonating large peaks for piles with bulging and necking.
On Spatial Layout Patterns of Harbin Songbei New District Under the Guidance of Smart Growth Theory
Authors: Wan Ting , Gu Yue , Xu Jian
Published: September 2011

Under the Guidance of Smart Growth Theory, the paper respectively discusses the spatial patterns including ecological network, waterfront accessible space and transit-oriented patterns through the analysis of project background and development conditions of Harbin Songbei New District Planning, and explores the functionally-integrated spatial layout patterns suitable for the development of Songbei New District through comparison and selection of various schemes, as well as analyzes the guidance and application of Smart Growth Theory in intensive urban development in order to propose reasonable measures and suggestions for the development planning of the New District.
Properties of Low-Density Lightweight Aggregate Concrete under Uniaxial Loading
Authors: Cheng Cong Mi , Su Da Gen , Jiao Chu Jie , He Juan
Published: September 2011

The aim of this study is to investigate the influence of EPS content on failure mode, stress-strain relationship and elastic modulus of expanded polystyrene aggregate concrete (PAC) with density lower than 900 kg/m3under uniaxial loading. The results show that PAC performs a good compressibility in the compression failure process. Apparent oblique crack appears in the case of uniaxial compression specimen damage; the lower the density is, the smaller the tilt angle of oblique cracks will be. Stress-strain curve of PAC with density larger than 422 kg/m3maintains a straight line relationship on ascending segment but varies with the density on the descent segment. The lower the density is, the larger PAC residual relative stress will become. Elastic modulus of PAC is proportional to 5.85 times index of relative density.
Corrosion Resistance of Reverse Pulsed Electrodeposition Nano-Nickel Coating
Authors: Wang Yan , Ge Wen , Yang Qian , Cheng Wen
Published: September 2011

With the purpose of decorative bright nickel plating process, nano-nickel and ordinary bright nickel coatings were prepared by applying the electro-deposition method with DC and PRC respectively. The grain sizes, organizational structures and surface morphologies of samples were characterizated by X-ray diffraction(XRD) and scanning electron microscopy (SEM) analysis. The corrosion resistance of the samples were determined by immersion corrosion test, salt spray corrosion test and electrochemical methods. The results showed that the corrosion resistance of reverse pulsed electrodeposition nano-nickel coating is superior to the DC electrodeposition nickel coating.
Experimental Evaluation on Fixed End Supported PFRP Channel Beams and LRFD Approach
Authors: Thumrongvut Jaksada , Seangatith Sittichai
Published: September 2011

In this paper, the experimental results on the fixed end supported PFRP channel beams subjected to three-point loading are presented. The aims of this study are to evaluate the effects of the span (L) on the structural behaviors, the critical buckling moments and the modes of failure of the beams, and to compare the obtained critical buckling moments with those obtained from the modified LFRD steel design equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 76x22x6 mm, with span-to-depth ratio (L/d) ranging from 13 to 52. A total of twenty-six specimens were tested. Based on the experimental results, it was found that the loads versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general modes of failure are the flexural-torsional buckling. Finally, the modified LFRD equation can satisfactorily predict the critical buckling moment for L/d exceeds 20. However, for L/d < 20, the equation overestimates the critical buckling moment of the beams and more development is needed.
Limit Wind Loads of a Concrete Filled Steel-Tube Transmission Tower
Authors: Xiong Tie Hua , Liang Shu Guo
Published: September 2011

Limit wind loads of a Concrete Filled Steel-Tube (CFST) transmission tower in a long-span tower-line system is computed. Firstly, fine Finite Element Method (FEM) model of the tower and its Multiple-Degrees-Of-Freedom (MDOF) model are built and the material nonlinear models including steel-tube and CFST are also modeled. Secondly, based on MDOF model, mean displacements under mean wind force are evaluated and the Root Mean Square Displacement (RMSD) under fluctuating wind force is also evaluated by random vibration theory. Then, Equivalent Static Wind Loads (ESWL) are computed considering the first three order modes. Finally, based on FEM model, the nodes are loaded by the ESWL and the nodal loads increase step by step in order to impel materials into plastic status until calculation can not converge. Plastic analysis shows the tower’s failure is caused by steel-tube element failure and the CFST elements have enough strength reserve. The tower’s three kinds of limit wind loads are computed based on different references and it is suggested to select the limit wind loads, whose corresponding wind velocity is 69.7m/s, as the design limit wind loads of the tower.
Numerical Simulation and Analysis for the Flow Field of the Main Nozzle in an Air-Jet Loom Based on FLUENT
Authors: Liu Ding Ding , Feng Zhi Hua , Tan Bao Hui , Tang Yin Ping
Published: September 2011

Due to the complicated structure and the high speed turbulence, it is difficult to measure and analyze the flow field characteristics of the main nozzle by experimental methods, naturally, some software such as FLUENT become a powerful tool to perform the numerical simulation for flow field of the main nozzle of an air-jet loom. The distribution of the airflow velocity and static pressure along axial and radial direction in main nozzle were investigated. The results indicated that the airflow in the main nozzle was extremely complex, its velocity in throat could be sonic and a certain backflow was produced. The research results will play an important role on the structural parameters optimization and energy conservation.
An Action Reversible Mechanism with Piezoelectric Actuator
Authors: Tang Yu Juan , Wang Jiong
Published: September 2011

At present, the explosion isolator of the fuze safety system using stepping motor or based on the slider continuation move realized safe state restorability, but the former is restricted by the volume of stepping motor, however, the stepping motor is vulnerable to electromagnetic interference; the latter structure is complex, with several independent components, not compact and irreversible. In view of this, an action reversible mechanism based on piezoelectric actuator is proposed, realizing the fuze safety system reversibility. The principle of the piezoelectric actuator is described and the drive mechanism is designed. The feasibility is analysed. The study shows that the mechanism has the certain practical value for compact structure, small volume and reliable actuation.
Research on Fast Locating Solder Joint on Fully-Automatic LED Wire Bonder
Authors: Huang Zhi Chao , Liu Mu , Liu Hua Dong , Fan Xing Ming , Zhong Yi
Published: September 2011

A new method is put forward to positioning solder joints on fully-automatic LED wire bonder. In the method, the image of a LED micro-chip is first processed with GPU by median filtering based on average and adaptive window size. Then the potential areas of the micro-chip are determined by the algorithm of adaptive threshold for image. These potential areas are stored in groups according to distances. The best potential area of each group is screened out in terms of symmetrical features of grey scale after that it is a weighted process. Finally, the LED micro-chip solder joint is precisely located by calculating the center of mass. The results show that the proposed method is fast, accurate, effective, suitable for automation, and has no requirement to the consistency of the shape of LED micro-chips.
Least Squares Phase Unwrapping Algorithm Based on Topographic Factors
Authors: Liu Wei Ke , Liu Gou Lin , Zhang Xiao Qing
Published: September 2011

The phase of complex signals is wrapped since it can only be measured modulo-2; unwrapping searches for the 2-combinations that minimize the discontinuity of the unwrapped phase, as only the unwrapped phase can be analyzed and interpreted by further processing. Weighted least squares phase unwrapping algorithm could avoid errors transmission in the whole phase images, but it could not avoid defect and overlay of interference fringes caused by topographic factors. Therefore, a new phase unwrapping and weights choosing method based on local phase frequency estimate of topographic factors was presented. Experiments show it is an efficient phase unwrapping method which well overcome the defect of under-estimate slopes by least squares algorithm, and has higher accuracy and stability than other methods.
Seismic Damage Information Extent about the Buildings Based on Low-Altitude Remote Sensing Images of Mianzu Quake-Stricken Areas
Authors: Zeng Tao , Yang Wu Nian , Li Xiao Dong
Published: September 2011

Using large-scale true-color images of Zundao Town of Mianzhu quake-hit areas gained form low-altitude remote sensing platforms, the author processed those images based on the 3S and image processing technology, then to presents a new object-oriented scheme of damaged building information extraction in the 5.12 Earthquake from the high-resolution low-altitude remote sensing in Zundao Town of Mianzhu. The scheme has two steps. The first step is that the whole imagery was segmented into image objects which do not intersect mutually. The second step is that to extract damaged buildings and undamaged ones with the features used to classify, like spectral, texture, shape and context. The experimental results indicate that the fast image processing method of UAV and the new object-oriented information extraction technique have high accuracy compared to the traditional classification methods and have a great application potential.
Test Study on Fatigue Property of Sheet Steels for Automobile
Authors: Zhang Xiao Peng , Li Ri Cheng , Xing Huai Nian
Published: September 2011

Automobile body sheets mainly resist impact and pressure. However, the fatigue property is one of the main factors with regard to properties of sheet steels. Continuous vibration happens all over the sheet steels (especially chassis) while the vehicle is in motion. And the fatigue property becomes particularly important in the condition above. Fatigue tests are conducted to four kinds of thin sheet steels for automobile in this paper. The fatigue lives of samples from sheet steels are obtained according to the various stresses. The inferior limits of fatigue life and the inferior limits of fatigue strength under the higher stresses are acquired by the computation of fatigue data. Furthermore, the test results show that there is a certain relationship among the tensile strength, yielding strength and inferior limit of fatigue strength for these sheet steels. This paper is of certain reference significance for other similar test.
A Wireless Microbial Fuel Cell Voltage Data Acquisition System Based on MSP430F149
Authors: Liu Kai , Zhao Zhi Wei , Jiang He Long
Published: September 2011

A wireless data acquisition system based on MSP430F149 is developed for the measurement of microbial fuel cells’ voltage. The main function of this system is to convert the analog input voltage into digital output code, process the digital code, and transfer the data through the GSM network or the USB interface. The core of the data acquisition device is a 16-bit general purpose Texas Instruments ultralow-power microcontroller MSP430F149. As the voltage of a microbial fuel cell is very low, the A/D converter circuit is specifically designed for high precision and high accuracy. A real-time clock is used to achieve timing measurement and the time interval can be set to meet demands. The data collected is transferred through the GSM network. Besides, a Windows environment application developed with Visual C++ can be used to access the data stored in the flash memory through USB interface.
A Practical Mathematical Model for Nonlinear Hysteresis of Metal Rubber Isolator
Authors: Zhou Yan Guo , Qu Wen Zhong , Xiao Li
Published: September 2011

The hysteresis dynamic behavior of metal rubber mathematically modeled with a practical method is studied, and the method of parameter separated identification is presented with details. Parameters of the model are identified with the test data of metal rubber, from which the theoretical loops are reconstructed, and the mechanism of the nonlinear damping behavior of the metal rubber is investigated. The theoretical loops and the experimental one are close to each other with satisfactory accuracy. The result shows that with the simple mathematical form and the satisfactory precision, the mixed damping model can be used effectively in practical engineering. This study provides a practical and effective method in modeling and the parameter identification of the metal rubber isolator.
The Vibration Analyses of Motorcycle Exhaust System and Suspension-Point Improvement
Authors: Hu Guo You , Xia Pin Qi , Wang Xing Xing , Lu Wen Feng
Published: September 2011

For the relatively strong vibration caused by a three-wheeled motorcycle exhaust system and raised the level of the noise in the whole motorcycle, this paper combines the experimental modal analysis method and finite element analysis (FEA) method, establishes finite model of the exhaust system, finishes the experimental modal analysis and transient response analysis based on Hyperworks software and laboratory equipment, and obtains six natural frequencies and mode shapes. Comparison has been made between acceleration RMS changes before and after the mounting points changed with the transient excitations. At the end, the document also verifies better results after the improvement and found the basement of reducing noise in the next step.
Research on Construction Mechanics Performance and Measured Results of SRC Ultra High Connected Structure
Authors: Wang Yong Quan , Guo Zheng Xing
Published: September 2011

To correctly acquire steel strain and deformation of SRC during construction process, one SRC transfer storey used in ultra high connected structure is chose. By nonlinear finite element method and field measurement, research on steel beam strain and deformation of the SRC connected structure in the whole construction process is performed. Based on practical construction method, the numerical analysis model for the construction process is established. Combined with time-variation mechanics and nonlinear finite element method, construction mechanics of the SRC transfer storey is analyzed, considering temporary support and construction load in each construction stage. Meanwhile, the field measurement of SRC transfer storey is carried out, and then the comparison between calculate result and measured value. The results show that, calculate result tallies closely with measured value, the steel beam is in a low stress state in the whole construction process, and the deformation of SRC structure varies linearly. The conclusion is that, mechanical behavior of the SRC transfer storey in the whole construction process can be grasped by nonlinear finite element method, and also the reliability of such structures in construction period and service life.
Research and Simulation on the Kinematics of a Modular Robot
Authors: Cui Yu Jie
Published: September 2011

This paper presents a modular robot called RBT-6T/S01SM. This robot composed of 6 basic modules which could composed 5 kinds of robot. Each module owns one rotational degree of freedom. The total combined robot RBT-6T/S01SM features an easy-to-build mechanical structure. A formulation of this robot is educed based on Denevit and Hartenberg in this paper.The kinematics is studied and inverse kinematics is obtained based on algebraic method. The kinematics simulation of RBT-6T/S01SM is presented based on Matlab. The effectiveness of kinematics equations is verified by the simulation results.
High Precision Measurement of Moment of Inertia Based on Compound Pendulum
Authors: Hou Wen , Xue Peng Fei , Ma Tie Hua
Published: September 2011

A new method and equipment based on compound pendulum was designed for measuring moment of inertia (MOI). The measurement principle of the system, being quite different from the traditional method which records the swing period of the compound pendulum, records the “Angle-time” curve and conducts a series of computation featuring phase-plane to obtain the MOI of the object being measured. The proposed method could effectively eliminate the friction moment’s influence on the measurement results and enhance the precision up to 0.12%. The method is suitable for the heavy and large-scale objects, especially those with large length/diameter ratio.
Effect of Nano-Carbides on the Microstructure and Mechanical Properties of Ti(C,N)-Based Cermets
Authors: Lei Yan , Liu Jing Fu , Yang Bing
Published: September 2011

In this paper, Ti(C,N)-Based cermets with addition of nano-carbides were fabricated by conventional powder metallurgy techniques. Then the mechanical properties, microstructure and corresponding formation mechanism have been investigated. According to the results, the microstructures of sintered cermets are composed of three kinds of hard grains: one with black core/grey shell, one with white core , and the other with no core. In addition, with more nano-carbides adding, the number of white core grains increases and that of black core grains decreases. It is also found that sintered cermets with nano-carbide additions exhibit higher transverse rupture strength and higher hardness than the others originated from much finer and more homogeneous microstructure. However, cermets with nano-micro carbide additions show the most poor mechanical properties among all sintered cermets, including conventional cermets, due to the obviously heterogeneous microstructure. And this can be explained by Ostwald ripening theory.
Comprehensive Evaluation of Spatial Form Planning for Campuses of Newly-Upgraded Undergraduate Universities
Authors: Yang Xian Jun , Deng Yun Ye
Published: September 2011

According to the analysis on the present situation and development tendency of the campus spatial form planning of newly-upgraded undergraduate universities as well as its functions and characteristics,15 evaluation indices were ascertained and the comprehensive evaluation model of the planning was established by the method of AHP (Analytic Hierarchy Process). The results showed that AHP can effectively ascertain the evaluation indices system. Through calculating the weight of each index and judging the consistency of matrixes, key factors that can influence the campus spatial form planning were obtained, such as the public green space, landscape node, visual contact axis, landscape axis, central plaza and teaching group space.
Studies of the Stability of Submarine Pressure Hulls with Non-Uniform Circular Ring-Frames
Authors: Cheng Yan Xue , Pang Yong Jie , Yang Zhuo Yi
Published: September 2011

To improve the general stability of submarine pressure hulls, this paper brings forward that redistribute the stiffness of the ring-frames according to the radial displacement of the buckling shell instead of uniform circular ring-frames. With energy methods, the formula of general buckling pressure is deducted in this paper. Some pressure hulls of different thickness with different number of frames are taken as examples. This method turns out to be effective on raising the general stability of ring–stiffened cylindrical shells by both the formula calculation and finite element analysis.
Research on RS-WNN Integrated Modeling
Authors: Xu Zong Chang , Tang Xue Qin , Huang Shu Feng
Published: September 2011

Wavelet Neural Network (WNN) integration modeling based on Rough Set (RS) is studied. An integration modeling algorithm named RS-WNN, which first introduces a heuristic attribute reduction recursion algorithm to determine the optimum decision attributes and then conducts WNN modeling, is proposed. This method is adopted to more effectively eliminate the redundant attributes, lower the structure complexity of WNN, which reduce the time of training and improve the generalization ability of WNN. The result of the experiment shows this method is superior and efficient.
Isogeometric Analysis of Heat Transfer in Fluids
Authors: Zhang Wen Lei , Mo Rong , Wan Neng , Zhang Qin
Published: September 2011

This paper is devoted to the numerical simulation of heat transfer in fluids. We develop a numerical formulation based on isogeometric analysis that permits straightforward construction of higher order smooth NURBS approximation. Firstly, we introduce the partial differential equation (PDE) which servers as basis for the whole paper. Then, we introduce Lagrange multiplier method to deal with essentional boundary contions accroding to the nature of NURBS basis function. After getting the Equivalent integral equation, the isogeometric solving format is established based on the idea of isoparametric which is the necessary fundamentals of Isogeometric Analysis. We also discuss the programming algorithm of isogeometric analysis based on Matlab. Finally, a numerical example in two dimensions is presented that illustrate the effectiveness and robustness of our approach.
Design of the Miniaturized Receiving Antenna Applied in the Detection of Corona Discharge Signals
Authors: Han Xiao , Chen Xi , Li Peng Fei
Published: September 2011

Corona discharge is a kind of self maintained discharges that occurs in the extremely uneven electric field which often happens in the industrial and daily living environments. In this paper, we study the characteristics of corona discharge, especially the ones in the time domain and frequency domain of negative corona discharge. Based on the analyzed characteristics mentioned above, we design and optimize a kind of patch antennas, which has the advantages of small volume compared to the traditional one used to receive the signals generated by corona discharge. This new antenna can be used in the field of security inspection on high voltage transmission lines applied in the industrial applications.
Studies on Cable’s Parameters Based on the Cable-Truss Mixed Model
Authors: Zhang Qing , Xue Li , He Tian Wei , Qin Xian Rong , Sun Yuan Tao
Published: September 2011

The steel strand cables can effectively stand for the horizontal wind load, enhance the lateral stiffness of the lifting stand, reduce the horizontal displacement of the tower and improve the overall stability. Based on a cable-truss mixed finite element model, in which the cables are simulated via the equivalent elastic modulus method, cable’s parameters, including the tilt angle, initial stress and layout of cables are analyzed. With the increasing of initial stress of cables, the lateral stiffness and overall stabalitily of the structure is improved greatly. And a certain range of tilt angle can effectively enhance the overall mechanical performances, insufficient or overlarge tilt angle are disadvantage of the overall structural strength and stability.
Numerical Simulation on Mean Flow past a Circular Cylinder Based on the Lattice Boltzmann Method
Authors: Yu Jian Ping , Yu Shu Rong , Liu Xing Wang
Published: September 2011

Lattice Boltzmann methods (LBM) have become an alternative to conventional computational fluid dynamics (CFD) methods for various systems. In this paper, flow field of mean flow past a circular cylinder was simulated based on the lattice Boltzmann method. The streamline of air past the cylinder illuminated that the fluid adhere on the boundary and doesn’t separate from the surface of cylinder when Re number less than 5. When Re number equal 40, flow separated to form a pair of recirculating eddies can be observed. With the Re number increasing, the trailing vortex length is growth accordingly. When Re number come up to 80, the trailing vortex begin to shed regularly. This result is consistent with the experiment data. Drag coefficient that fluid act on the surface of cylinder was calculated. The calculated results were same as the experiment data. Simulation indicate that LBM can simulate the vortex taking place and shedding effectively.