bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsteady Wake Effect on Film Cooled Rotating Blade
Authors: Zhang Ling , Wang Shan Ru , Lv Min
Published: September 2013

Vane-wake unsteady characteristics and its effects on rotor blade leading-edge were investigated with SST k-ω turbulence model in this paper. Conditions of different rotated speed (500rpm, 1000rpm, and 2000rpm), rotor blade surface static pressure and heat transfer coefficient distributions were obtained from spectrum analysis of rotor surface lift and drag coefficient under corresponding conditions. Results show that: Along with the increase of speed, wake vortex shedding frequency and energy entropy around rotor blade flow field increase, which leads to relatively high energy loss; pressure surface of rotor blade static pressure reduces with increasing speed, whereas, suction surface static pressure increases, and overall heat transfer performance of rotor blade surface increases.
The Vertical Axis Wind Power Controller Design
Authors: Bai Xue Feng , Li Pei , Li Hong , Song Xiao Na , Wang Cheng Wei
Published: September 2013

The use of renewable energy plays an important role in the sustainable development of our social economy and environmental protection. Wind power is now one of the fastest growing forms of renewable energy. these can be steady and predictable, providing a clean, safe and potentially limitless source of power. Now, Small wind turbines use the battery energy storage. Due to the randomness of the wind power and wind speed change range is larger, it is difficult to charge a battery. In this paper ,we will introduce a set of small vertical axis wind power controller system designed that is small size, light weight, high efficiency and energy saving, good load effect , good dynamic performance, reliable work and stable output .bridge rectifier circuit, MCU and its peripheral circuit, AD conversion circuit and serial communication circuit are put into use. charging control and discharge protection are controlled by microcontroller.
Research on Neutral Grounding Reactance Allocation with MCR
Authors: Liu Ren Wei , Yin Zhong Dong , Cao Song Wei , Ma Heng Rui
Published: September 2013

For the arc current generated during the reclosing of the high-voltage transmission system, small reactance configuration compensation and control strategy. By the magnetically controlled reactor is researched. First analyzing the principle that high-pressure single-circuit and double-circuit on the same pole line suppresses arc current, then establishing the magnetron controlled reactor equivalent model in PSCAD, on this basis, establishing simulation using magnetron reactors to suppress secondary arc current circuit under the conditions of high voltage transmission lines , designing and implementing of a magnetic valve controllable reactor inhibition of arc current physics experiments under of a low-voltage experimental conditions analoging high-voltage actual line condition. At last, the comparison of PSCAD simulation waveform and physics experiments of Power Quality the analyzer topas2000 and oscilloscope output verify the magnetic valve controllable reactor to suppress the arc current theory feasibility and effectiveness.
The Derivation and Simulation of Curved Tooth Face Gear Tooth Theoretical Contract-Point Trace Line Equations
Authors: Peng Xue Yu , Li Qing , Wang Tai Yong
Published: September 2013

The face gear tooth surface theoretical equation, based on the mesh of curved tooth face gear and involute worm, was deduced by means of differential geometry, meshing theory and so on. According to the conditions of the gear meshing, studying the ideal contract-point trace line theoretical equation under the conditions of no machining errors, installation errors and so on. By solving the equations and simulating in SOLIDWORKS, finally the tooth contact situation of face gear and cylindrical worm in the meshing process was got.
Development of Off-Line Inspection System on Equipment Based on Embedded Linux Technique
Authors: Sun Hua Min , Shen Hai Kuo , Wang Tai Yong , Nie Meng
Published: September 2013

In order to meet the requirements of the business enterprises for equipment monitoring instruments, an embedded data acquisition and analysis system based on Linux technique has been developed, and its hardware configuration and software structure were described. The system incorporates many functions in a unit, including data acquisition, real-time display, storage, analysis, and communication, etc., and has a high scalability, maintainability and reliability. The experiment results showed that its functions is stable, and can be widely used in the system monitor and diagnosis in various equipment and installations.
Centralized Monitoring Method for Isomeric Heat Treatment Equipments
Authors: Xiao Xin Hua , Yang Xiao Feng , Yu Hong Bin , Peng Jun Qiang
Published: September 2013

Heat treatment equipment are usually harmful to people, they need to be monitored remotely. As the fact that different types of equipment are used in factories, which leads to the problem that monitoring equipment is difficult. Therefore, research on remote centralized temperature monitoring system is necessary. The concept of isomeric equipment is proposed. The framework of monitoring system is established, which is constituted of temperature control instruments, monitoring server and clients. The functions of monitoring system are described, such as setting temperature, receiving temperature, showing the chart of temperature, accumulating and reusing heat treatment experience etc. The key technologies of monitoring system including dynamic protocol adapter and knowledge accumulation and reuse are also explained. Finally, the system is applied in a factory. The engineer can monitor almost all of the heat treatment equipment only by use the system in the office.
Research on Agricultural Harvester Data Detection System Based on Remote Monitoring
Authors: Guo Xiao Jun , Gao Lei Lei , Wang Tai Yong , Li Zhen Nan
Published: September 2013

On-line detection system of the harvester is an outcome from combination of modern computer technology and communication technology in harvester operations applications. With the help of the various sensors, the harvest yield, running routes, and threshing wheel speed, etc. are measured. These information and parameter are indicator of the harvesters working status. They are detected, processed, packed, and transmitted to the computer server in monitoring center via a wireless network. On the monitoring center server, the transmitted data is processed further, fault data are inspected, reliability data is calculated. Meanwhile, the harvester is controlled according to accepted data.
The Construction of the Workpiece Coordinate in CNC System Based on Motion Control Card
Authors: Liu Heng Li , Hu Shi Guang , Wang Tai Yong , Wang Dong
Published: September 2013

Based on motion control card, it analyzed the methods and principles of the workpiece coordinate construction used the G54; created the G54 function modules, embedded CNC system of independent research and development and improved the system functions, processing efficiency and quality. The method described in the article can be directly applied to the machine tools controlled by numerical control system based on the card, and had a high practical value to the establish of other CNC machine tool workpiece coordinate system.
Application of DIC System in the Tensile Test of Medium and Heavy Plate
Authors: Yu Ai Wu , Zhu Chuan Min
Published: September 2013

Digital image correlation (DIC) is a kind of non-contact strain measurement method. It could provide deformation information of a specimen by processing two digital images that are captured before and after the deformation. the application of DIC method in performance testing and evaluation of new materials has great superiority over the traditional methods in the aspects that help to explore the features of new materials, such as mechanical performance, deformation mechanism and dynamic and static performance[1-. Tensile test of 8mm steel plate based on DIC is introduced in this paper, this test is easy operated and high accuracy. It can not only get all the data that traditional method done, but also reflect the full range strain, strain history and strain rate. It can also transform the result among different type strain. The experiments based on DIC method of medium and heavy plate can help to learn the properties of material like this kind much more comprehensively, reduce testing time and promote the wide application of new material in manufacturing.
Research of Control Strategy Based on the Electro-Hydraulic Proportion Position Control System
Authors: Zhu Yin Fa , Chen Bing Bing
Published: September 2013

The self-tuning fuzzy PID controller of the electro-hydraulic proportion position control system is designed and researched. Compared the self-tuning fuzzy PID control with the traditional PID control through experiments for the track effect on sinusoidal signals, the results show that the self-tuning fuzzy PID controller has higher accuracy and better stability. It is a more excellent performance controller.
Research on Acoustic Source Localization Technology Based on Cross-Correlation
Authors: Xie Zhi Jiang , Zeng Hai , Chen Ping
Published: September 2013

In order to realize acoustic source localization, we proposed to use microphone array and time delay based on crosscorrelation algorithm,and analyzed the factors to influence the locating accuracy, and established a realtime acoustic source localizationsystem on the NI CompactRIO system. By experiments, cross-correlation algorithm for wideband signal(sweep signal, noise signal) localization is more accurate, for narrowband signal (organ signal) localization is less significant. After analyzed factors to influence the localization accuracy, we improved sound source system, and the factors that affected the organ signal localization is verified by experiment , and improved accuracy of narrowband signal localization .
The Error Caused by Order Analysis for Rolling Bearing Fault Signal
Authors: Cheng Wei Dong , Gao Robert X. , Wang Jin Jiang , Wang Tian Yang , Wen Wei Gang , Li Jian Yong
Published: September 2013

Defect diagnosis of rolling element bearings operating under time-varying rotational speeds entails order tracking and analysis techniques that convert a vibration signal from the time domain to the angle domain to eliminate the effect of speed variations. When a signal is resampled at a constant angular increment, the amount of data padded into each data segment will vary, depending on the rate of change in the rotational speeds. This leads to changes in the distance between the adjacent impulse peaks, and consequently, the result of order analysis. This paper presents a quantitative analysis of key factors affecting the accuracy of order analysis on rolling element bearings under variable speeds. An analytical model is established and simulated. The effects of speed variation, instantaneous speed, angular interval between impulses, and the rising time of impulse are specified. It is concluded that the results of order analysis will be smaller as the rotational speed increases, and becomes larger when the speed decreases. Furthermore, the error is larger under low speeds than high speed.
Fault Diagnosis of Rolling Bearing Based on Dual-Tree Complex Wavelet Transform and AR Power Spectrum
Authors: Meng Zhi Peng , Xu Yong Gang , Zhao Guo Liang , Fu Sheng
Published: September 2013

Aiming at the strong background noise involved in the signals of rolling bearing and the difficulty to extract fault feature in practice, a new fault diagnosis method is proposed based on Dual-tree Complex Wavelet Transform (DT-CWT) and AR power spectrum. Firstly, the non-stationary and complex vibration signal is decomposed into several different frequency band components through dual-tree complex wavelet decomposition; Secondly, Hilbert envelope is formed from the components which contains the fault information. Finally, the auto-power spectrum can be obtained by auto-regressive (AR) spectrum. The noise interference was eliminated effectively, and the effective signal information was retained at the same time. Thus, the fault feature information was extracted. In this paper, the fault test and the engineering practical fault data of rolling bearing were analyzed by dual-tree complex wavelet transform and AR power spectrum. The results show that the noise of the vibration signal was eliminated effectively, and the fault feature were extracted. The feasibility and effectiveness of the method were verified.
Establishment of Cutting Model for Three-Axis Surface Machining Based on SolidCAM
Authors: Lin Fu Xun , Wang Qi Chen , Wu Kai Fa , Liang Ruo Yu , Wang Xian
Published: September 2013

For different three-axis machining characteristics, SolidCAM provides many machining strategies including linear, correction, spiral, imitation cutting and so on. This paper chooses three-axis revolving curved surface parts as the research object and reference three-axis stereo processing combinating wrap-around roughing and linear processing. Finally, the cutting model of this machining strategy based on parameters has been established to provide a reference for the determination of cutting parameters.
An Improved Parallel Computation Method for Delaunay Triangulation
Authors: Chen Zhi Yu , Fu Jian Zhong , Shen Hong Yao , Gan Wen Feng
Published: September 2013

Amongst the flourishing Delaunay Triangulation methods, growth algorithm has been widely accepted because of its reputation of being simple and elegant. However, the parallelization of growth algorithm has not been fully exploited. In this work, a novel Growth algorithm of Delaunay Triangulation is proposed. The point cloud is first divided into two parts by a suitable curve and the separated areas are calculated by incremental algorithm. Triangles which cross with the curve are generated by a growth algorithm associated with uniform grid. At the process of merging, these grew triangles are used to detect incorrect triangles of the incremental algorithm areas. Method about generating triangles on curve is elaborated and a simple way to detect interferential triangles is also explained. With above method, triangulation calculation can be parallelized. Unlike the traditional divide-and-conquer method, no flip operation is needed in the proposed methodology. Thus, three dimensional applications are also made possible. A comparative research between tradition incremental algorithm and the proposed method has been conducted. Results show, the algorithm has a higher performance with less computation time.
Case-Based Reasoning Rapid Design Approach for CNC Turret
Authors: Wang Hai Qiao , Sun Bei Bei , Shen Xian Fa
Published: September 2013

In order to provide more efficient knowledge services in the CNC turret design process, a rapid design method of a case-based reasoning is proposed. Firstly, according to different types of demand in case retrieval, the similarity measurement models for crisp and fuzzy attribute type demands are constructed respectively. Secondly, in the weights assignment, this paper utilized the deviation information of similarity values to calculate objective weights, and then combined the objective weights and subjective weights to form synthesis weights. Finally, the similarity measurement and weights coefficient assignment methods were applied in a CNC turret design CBR system, and using the calculation function of MATLAB. It was demonstrated that this method could improve the accuracy of case retrieval.
Design and Implement of a Low Cost Drop-on-Demand Inkjet Printing System
Authors: Wei Zi Yuan , Wu Sen Yang , He Yong , Fu Jian Zhong
Published: September 2013

Nowadays, drop-ondemand inkjet printing technology has shown its potential in many fields. This paper presents designing and implementing of a low cost drop-ondemand inkjet printing system. Inkjet printing system can be divided into four parts, and back pressure control system and droplet observation system are two key components, both of which are described in details. In order to have a further control of accuracy and stability of the system, this paper discusses the parameters designed in the system. In pressure control system, the designed system has higher accuracy compared with the Microfabs product. Images can be taken through CCD camera instead of ultra-high-speed camera by using droplet observation system. Some experiments also have been done to verify the feasibility of the device. Accuracy of pressure control, stability of the system and reproducibility of inkjet process can be verified from the experiment.
The Topology Optimization of the Car Sub-Frame Based on APDL Language
Authors: Li Jian Min , Yang Zhang Cheng , Sun Chuan Yang , Xie Hai
Published: September 2013

Using APDL language, the car sub-frame finite element parametric model is created. It indicates that the emergency braking is the dangerous conditions of sub-frame. The sub-frame is topology optimized under the emergency braking, and gets the element pseudo density distribution map; By modifying the model according to the pseudo-density, the optimization results meet the design requirements. Compared to the original model, it gets a 9.05% reduction in volume, and achieves lightweight of the sub-frame.
The Self-Synchronization of a Novel Vibrating Mechanism Excited by Two Unbalanced Rotors
Authors: Li He , Liu Dan , Wen Bang Chun
Published: September 2013

This paper proposes an analytical approach to study self-synchronous motion and stabilizing conditions of a novel vibrating mechanism excited by two unbalanced rotors. This approach begins with utilizing Lagrange equation to establish differential motion equations of the system, and then obtains the dimensionless coupled equation of the unbalanced rotors with a modified average small parameter method. The zero solutions of dimensionless coupled equations are used to achieve the condition to implement self-synchronization of the vibrating system, and finally the Routh-Hurwitz criterion is used to derive the conditions of self-synchronous motion stability.
Transition Segments Processing Method Based on Curve Fitting Algorithm
Authors: Zhang Yue , Liu Qing Jian , Liu Lu , Wang Tai Yong
Published: September 2013

In order to obtain better speed and high accuracy, real-time curve fitting and fitting processing at transition points are often necessary when machining complex contours. Based on the quadratic trigonometric Bézier curve, a new algorithm is presented to realize curve fitting only between transition segments. This method ensures the machining precision and increases the maximum allowable speed at the transition points. Simulation and experiment results show that the transition velocity changes smoothly and steadily as well as the processing efficiency is promoted.
Compiling Research and Realization of 3D Cutter Radius Compensation Based on PMAC
Authors: Wang Dong , Hu Shi Guang , Liu Qing Jian , Chen Dong Xiang , Wang Tai Yong
Published: September 2013

This text introduces the compiling research and realization of 3D cutter radius compensation based on PMAC in Five-Axis NC Machines. First, the importance of 3D cutter radius compensation to machining programming of complicated curved surface will be talked about. Then we will present the theory and accomplishment of this function. Finally, based on the train of thought, an experiment will be done on Five-Axis NC Machines. As can be seen from the result, the method, simple and right, can manufacture components with multiple-axis tandem that satisfy complicated curve accuracy class.
Rapid Reverse Modeling for a Boring Bar with Complex Surface
Authors: Liang Hong Qiang , Yuan Li , Peng Wei , Zhu Ping Yu
Published: September 2013

For some product development processes, reverse engineering (RE) allows to generate surface models by using the coordinate measuring machine (CMM) scanning technique, for this methodology permits to manufacture different tools in a short development period. A case study on a boring bar with complex surface is present for a brief overview of RE and provide benefits to improve the efficiency of designing and production processes. In order to guarantee the precision of the boring bar model, two methods of software Imageware for rule surface reconstruction and NURBS fitting are used. According to compare experimental modal data with simulation modal data, verified the viability of rapid reverse modeling for damping boring bar.
Mechanical Components Design and Research Based on Reliability
Authors: Zhao Shu Ying , Yang Chen Sheng
Published: September 2013

In this paper, the reliability design method was used during the process of mechanical parts designing, the design parameters was regarded as random variables, the reliability index of products was involved in the design of the entire process, making the design more in line with the results of the actual situation. The general process of the reliability design was explained by the design of typical part. A good method to effectively improve product quality, reduce part size, save materials and reduce the cost was founded, and the same time the method can make the design of the products more competitive in the market.
Modeling Cutter Engagement Region for Triangular Mesh
Authors: Gan Wen Feng , Shen Hong Yao , Lin Zhi Wei , Chen Zhi Yu , Fu Jian Zhong
Published: September 2013

Cutter Engagement Region (CER) is the part of tool that contacts with stock, where a series of energy exchange and material transportation take place. A full understanding of its shape and area is indispensible for cutting force calibration, chatter analysis, and tool wear prevention. It can provide a criterion for efficient tool-path planning as well. In literature, however, there is no available modeling of CER. We hereby propose a modeling method for ball-end tool with design surface represented in triangular mesh. First, design surface is offset to form a stock surface. Next, compute the intersection between every triangular facet and the tool. Then, connect all the intersecting arcs to form the boundary of CER. Finally, compute the area of CER. Experimental validation for the proposed method is still needed.
Performance Evaluation and Prediction of Escalator Structure Using FEM-Based Analysis
Authors: Zhao Jian Cai , Chen Xi , Zhao Ze Yu
Published: September 2013

The paper applied Finite Element Method (FEM) to study performance of escalator structure. A case study is given to demonstrate the method of the FEM. To validate the results of FEM, some experiments were conducted. The results show that all the test samples meet the requirements of the truss, and the experimental results verify the numerical calculation results.
Research on the Dynamic Characteristics of NC Boring Machine Spindle System Based on Finite Element Analysis
Authors: Jiao Feng , Sun Guang Ming , Liu Jian Hui
Published: September 2013

In this paper, elastic hydrodynamic lubrication theory was introduced into bearing dynamic stiffness calculation process to take into account the impact of the oil film on the rolling stiffness. Dynamic characteristics of NC boring machine spindle system dedicated to the manufacturing of bearing retainer were studied based on finite element analysis software. The rationality of the structural design of spindle was verified in the paper. The research provided a theoretical basis for the improvement of machine performance and dynamic design of NC boring machine spindle.
Research on Thermal Error Compensation Instrument Based on Thermal Modal Analysis for NC Machine Tools
Authors: Yang Bo , Wang Yi , Yu Wen Li , Yao Xin Hua , Fu Jian Zhong
Published: September 2013

Great efforts have been made to improve the accuracy of NC machine tools, within which thermal error compensation is one of the most efficient ways. A new thermal error compensation instrument which is based on thermal modal analysis for NC machine tools is introduced in this paper. OMRONsCJ2M-CPU11 is used as microcontroller, and SAILING TECHNOLOGYs STA-A08 temperature measuring modules as temperature transmitter. Through hardware and software design, high precision and stability can be achieved. By measuring several key points temperature and making use of a thermal error compensation theory, real-time thermal error compensation can be output to the machine tool, thus thermal error can be reduced.
Research on Hydraulic Control System of Straightening Machine with Nine Rolls for Plates Based on BP Neural Network PID Controller
Authors: Li Song , Song Jin Chun , Ren Guan Gan , Cai Yan
Published: September 2013

A mechanical transmission equipment of traditional straightening machine for plates are driven by worm gear and worm, which causes small straightening force, slow pressing speed and low control precision. However, screwdown control system of straightening machine can be driven by hydraulic system, which will lead to large straightening force, rapid pressing speed and high control precision. This system was designed for straightening machine with nine rolls for plates, its transfer function was deduced, and the analysis on its stability and time response was conducted. A BP neural network PID controller was utilized in the system for improving dynamic characteristics. It can be concluded that the system responds rapidly, and stability and control precision are high if BP neural network PID controller is used in the system.
A Combined Error Model for Thermal Error Compensation of Machine Tools
Authors: Wang Wei , Yang Jian Guo
Published: September 2013

In this paper, a combined error model for thermal error compensation of machine tools is presented. Through the analysis of thermal error data of machine spindle at different temperatures, the error variation law is obtained. Experiments on the axial directional spindle deformation on a CNC machine center are conducted to build and validate the proposed models. The experimental validations show that the thermal errors of the machine tool are reduced effectively after applying the error compensation approach. The combined error model performs better than the traditional time series and neural network model in terms of prediction accuracy and robustness, which means that the new model is more suitable for complex working conditions in industrial applications.
Exploration on Grinding Temperature Field Based on Water Vapor Cooling
Authors: Zhao Li Gang , Ding Qing Ming , Ren Jia Long
Published: September 2013

To explore the influence of the water vapor cooling conditions on grinding temperature field of titanium alloy TC4 material, ANSYS simulation and test methods are adopted in this paper. Simulation and experimental studies show that: water vapor as coolant can reduce the surface temperature of the workpiece quickly by changing the wheel speed, workpiece speed and cutting depth; Water vapor cooling can control the grinding zone temperature below 400 °C on certain conditions, and compared with dry grinding it can reduce more than 50%; The grinding zone temperature can significantly be reduced by optimizing the grinding process parameters and improving the quality of the machined surface.
Establishment of Mathematical Relation Model between Dislocation Motion and Machining Deformation of Titanium Alloy Monolithic Component
Authors: Yang Yong , Li Ming
Published: September 2013

According to dislocation dynamics, a distribution equation of mobile dislocations during the deformation of monolithic component was established. Slip deformation was solved through dislocation density and Burgers vector, and then the mathematical relationship between slippage and plastic deformation was established. Thus the mathematical relation model between dislocations and the machining distortion of monolithic component was established by plastic deformation as intermediate variable. It is shown that the machining distortion of monolithic component is upward embossment, and its maximum deformation occurs near the middle of the beam. The amount of machining distortion is directly proportional to the stress field at different depths of the surface layer, proliferation strength of dislocation and the length of the work piece, and inversely proportional to the thickness of the work piece.
Mechanical Model of Non-Magnetic Particles Centrifugal Separation in Magnetic Fluid
Authors: Li Tong , Wei Jing Tao , Li Ji
Published: September 2013

It is difficult to sort fine non-magnetic particles only by the buoyancy of magnetic fluid. Therefore, based on the magneto hydrostatic separation, the centrifugal separation under the condition of centrifugal force would be an effective method to improve the efficiency. By establishing the mechanical model of centrifugal separation in magnetic fluid, this paper analyzes the kinematical equations of non-magnetic particles in three directionstangential direction, radial direction, and axial direction, and then theoretically explores the separation mechanism of this method.
Research on Sintering Polytechnic of PTFE/Al Reactive Materials
Authors: Wu Jing Bo , Li Mao Quan , Zhang Shu Hai , Mei Yun Long , Gao Ze Tao
Published: September 2013

PTFE/Al reactive material was prepared via a hot pressed sintering process and comparative experiments were conveyed considering heating rate, sintering temperature and heat preservation time. The internal microstructure of the material was investigated using metallurgical microscope and stereomicroscope. From the investigation the influence of process parameters of hot pressed sintering on the properties of the material were deduced, and the analysis was verified by testing the impact initiation property with drop hammer method. The density of the material was measured according to the Archimedean principle. and the results showed that the best operating conditions of these three factors are 80°C/h, 365°C, and 0.5h, This new method has a higher effectively (short process time) and need lower operation conditions (low sintering temperature and pressure) comparing with the traditional cold sintering process.
Synthesis and Characterization of Surface-Grafted Magnesium Oxide Whiskers with poly(L-lactide)
Authors: Wen Wei , Luo Bing Hong , Li Cai Rong , Xu Wan , Zhou Chang Ren
Published: September 2013

Firstly, Magnesium oxide (MgO) whiskers were prepared by calcination of magnesium carbonate (MgCO3)whiskers which were obtained by solution method. Then, surface-grafted MgO whiskers with poly (L-lactide) were synthesized by bulk ring-opening polymerization ofL-lactide onto the surface of MgO whiskers. The MgO whiskers and surface-grafted MgO whiskers were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), x-ray diffraction (XRD) and fourier transformation infrared (FTIR). Results showed that MgO whiskers diameter in the range of 0.02-0.5μm, the length is between 10-80μm and well dispersed. A new characteristic stretching vibration absorption peak of C=O apppeared in the IR spectrum of the surface-grafted MgO whiskers, which suggested that poly (L-lactide) chains were successfully grafted on the surface of MgO whiskers.
Effect of Nb Content on Microstructure and Properties of Microalloyed Rephosphorized Steel
Authors: Ma Chun Yu , Wang Chang , Yuan Jun Ping , Wu Hai Chao
Published: September 2013

The effects of Nb content on the microstructure and properties of microalloyed rephosphorized steel sheet are investigated by analyzing its microstructure and properties of as hot-rolled and as annealed. The results show that proper coiling temperature for full precipitation increases as Nb content increases. Mechanical properties varies as the annealing temperature increases because of precipitation coarsening behavior, it is bad for mechanical properties stability.
Study on Application of Intelligent Chromic Material to the Interior Design
Authors: Cui Wei , Hu Wei Ping
Published: September 2013

Continuous research and innovation on intelligent material in recent years have greatly contributed to it applied into in every field and holding an irreplaceable position. The intelligent chromic material, one kind of intelligent materials, can make a reaction contingent on its located environment factors, besides, having abundant colors and abilities of dynamic changes with a strong decoration and innovation. The paper mainly focuses on study and analysis on application of intelligent material to the interior design, and attempts to bring new functions and stronger adaptive capacity to environment to the interior space, which is devoid for the traditional decorative materials, for the purpose of amelioration of peoples life quality.
Flammability and Thermal Degradation of Polystyrene/Cadmium Sulfate Nanocomposites
Authors: Wang Zheng Zhou , Wilkie Charles A.
Published: September 2013

Cadmin sulfate nanoparticles, hollow sphere (CdS-HS) and rode (CdS-NR) were synthesized by ultrasonic and solvothermal process, respectively. The effect of the two kinds of nanoparticles on flammability of polystyrene was investigated using cone calorimeter (Cone) and microscale combustion calorimeter (MCC). Cone data indicate that the incorporation of 1% CdS nanoparticles leads to a about 20% reduction in the peak heat release rate (PHRR) compared to the pure PS; CdS-NR is more efficient in reducing the PHRR proved by both Cone and MCC results. The TG results show that the addition of the nanoparticles mainly increases thermal stability of PS at high temepratures.
Strength Analysis of Energy Storage Flywheel Wrapped with Composite Material
Authors: Li Hong , Pang Yi Meng , Xu Fang Fang , Li Li
Published: September 2013

The technology of flywheel energy storage is already widely used in motorcar, electric power systems, spaceflight and martial fields. Decreasing the weight, increasing rotating speed and strength of the flywheel rotor and improving the energy storage efficiency of the flywheel are always attention-getting. In this paper, the flywheel energy storage wrapped with composite material by interference fit to hub is designed and finite element analysis is done to obtain the stress distribution of it before being produced. The maximum and variety of stress are studied and the influence of composite material wrapped on flywheel rotating at a high speed is discussed. Then the action of composite material preload to the flywheel is thought about. The results of this analysis can prepare a valuable guide for flywheel energy storage at design and manufacture stage.
Assessment of UMTS and Averaged SED Fracture Criteria for U-Notched Specimens
Authors: Filipescu Hannelore , Caplescu Cristiana , Pasca Niculai
Published: September 2013

A set of mixed-mode I/II fracture tests was carried out on a polyurethane material. Using a single edge notched bend (SENB) type specimen, containing straight and respectively inclined U notches, the full range from pure mode I to dominant mode II was achieved. Two different fracture criteria were employed for the prediction of the fracture conditions: the UMTS criterion and the averaged SED criterion. Using these two criteria a set of curves were derived in terms of the fracture load vs. notch radius. The agreement between the experimental results and those predicted based on these two criteria is discussed finally.
Evaluation of Generalized MTS Criterion for Mixed-Mode Fracture of Polyurethane Materials
Authors: Negru Radu , Marşavina Liviu , Filipescu Hannelore
Published: September 2013

Using the asymmetric semi-circular bend specimen (ASCB) a set of mixed-mode fracture tests were carried out in the full range from pure mode I to pure mode II. The tests were conducted on two polyurethane materials characterized by different properties. The fracture parameters were obtained from experiments and are compared with the predictions based on the generalized MTS criterion (GMTS). The agreement between the experimental results and those predicted based on the GMTS criterion is discussed finally.
Length Influence on Stress Concentration in Orthotropic Plates
Authors: Sánchez Milagros , Troyani Nando
Published: September 2013

Results for stress concentration in short members for isotropic plates with centered circular holes have been reported in the literature. More recently the influence of length for orthotropic holed plates has been examined and published as well. However, important aspects of stress considerations were missing such as the influence of load direction vs. material orientation which happens to have a strong influence on stress concentrations. Additionally, implied important misleading inaccuracies were reported. This analysis is meant to provide essential corrections to the published material.
Lamb-Wave Based Technique for Multi-Site Damage Detection
Authors: Sharif-Khodaei Z. , Bacarreza Omar , M.H.Aliabadi Ferri
Published: September 2013

The propagation characteristic of Lamb waves activated by Piezoelectric actuators and collected by sensors in a stiffened panel has been investigated. A network of actuators is used to scan the structure before and after the presence of damage. A diagnostic imaging algorithm has been developed based on the probability of damage at each point of the structure measured by the signal reading of sensors in the baseline and damaged structure. A damage localization image is then reconstructed by superimposing the image obtained from each sensor-actuator path. Three-dimensional finite element model with a transducer network is modelled. Damage is introduced as a small softening area in the panel. Applying the imaging algorithm, the damage location was predicted with good accuracy. The validity of the algorithm was tested for multiple damages.
Surface Damage and Fatigue Strength of Ultrafine Grained Copper Treated by Mild Annealing
Authors: Teshima N. , Goto Masahiro , Han S.Z. , Euh Kwang Jun , Yamauchi K. , Kawagoishi Norio
Published: September 2013

Fatigue tests of ultrafine grained (UFG) copper produced by equal channel angular pressing (ECAP) showed negligible enhancement of fatigue strength in high-cycle fatigue regime. This was attributed to the thermal instability of UFG microstructure; a grain coarsening occurred during a large number of stress repetitions. Aiming at an enhancement of fatigue strength in the long-life field in excess of 107 cycles, post-ECAP mild-annealing for improving thermal stability was conducted. Grains with sizes up to a few tens of micrometers surrounded by fine grains were formed after the annealing as a result of discontinuous recrystallization. The improved stability of post-ECAP annealed micrstrucvture was related to the 9% increased fatigue strength in long life fields. The effect of bimodal microstructure on surface damage formation and fatigue strength was discussed.
Crack Deflection from the Interface between Two Orthotropic Materials-Effect of Higher Order Terms in Asymptotic Analysis
Authors: Damborský Petr , Ševeček Oldřich , Profant Tomáš , Kotoul Michal
Published: September 2013

The problem of crack deflection from the interface between two orthotropic materials is analyzed using the concept of Finite fracture mechanics and matched asymptotic procedure. A fracture criterion based on the energy approach is introduced for this problem. The main input for such criterion is the complex stress intensity factor calculated e.g. using the two-state integral. However for more precise predictions of the crack propagation also higher order terms of the asymptotic expansion are advisable to involve in the fracture criterion. To this end a T-stress term will be calculated and considered as the second input parameter. The matched asymptotic procedure together with FEM is used to derive the change of the potential energy induced by the incremental crack growth.
Numerical Lifetime Prediction of Polymer Pipes Taking into Account Residual Stress
Authors: Hutař Pavel , Ševčík Martin , Náhlík Luboš , Frank Adreas , Kučera Jaroslav , Pinter Gerald
Published: September 2013

In this paper a methodology for assessment of residual stress effects on crack behaviour in the polymer pipe is developed. For simplicitys sake, a linear distribution of residual stresses across the pipe wall is assumed. Linear elastic fracture mechanics is used for the fracture mechanics analysis of the cracked pipe. An approximate relation for the stress intensity factor estimation for a crack in a polymer pipe, with residual stress taken into account is suggested and discussed. The methodology presented can be helpful for a rapid lifetime estimation of polyolefin pipelines.
Virtual Testing for Fracture Toughness, Fatigue Crack Growth and Fatigue Life Data Estimation of Metallic Components
Authors: Pettinà Michele , Farahmand Bahram , Berto Filippo , Abdi Frank
Published: September 2013

Evaluating fracture and fatigue life properties of structural components involves tests that are costly and time consuming. To estimate total life of engineering parts, high cycle fatigue data (S-N) for the material under study is needed. In many cases the S-N data is not available to the analyst and both the time and budget required for testing prevent engineers to meet the deadline imposed on the program. An analytical combined Progressive Damage and Fracture Mechanics based approach is proposed that estimates the S-N data for components that have stress concentrations. The proposed methodology starts from a full engineering tensile stress-strain curve of the material under study and ends up with the estimation of fracture toughness, fatigue crack growth and fatigue S-N curves.
Damage-Involved Response of Two Colliding Buildings under Non-Uniform Earthquake Loading
Authors: Jankowski Robert
Published: September 2013

Pounding between insufficiently separated buildings, which may result in considerable damage or may even lead to the total collapse of colliding structures, has been repeatedly observed during earthquakes. Earthquake-induced collisions of buildings has been intensively studied applying various structural models. It was assumed in the analyses, however, that the seismic excitation is identical for all structural supports; whereas, in the reality, the ground motion differs from place to place due to spatial seismic effects connected with propagation of the seismic wave. The aim of the present paper is to conduct a detailed non-linear damage-involved analysis of pounding between two structures under non-uniform earthquake loading. A case of pounding between the Olive View Hospital main building and one of its stairway towers, observed during the San Fernando earthquake of 1971, has been considered in the study. In the numerical FEM analysis, non-linear material properties have been simulated using stiffness degradation (due to damage under cyclic loading) model of concrete and elastoplastic damage model of reinforcing steel. A method of conditional stochastic modelling has been used to generate the input ground motion records. The results of the study indicate that the incorporation of the non-uniform ground motion excitation may lead to substantial change of pounding-involved response of the structures. The difference between the uniform and non-uniform responses has been found to be relatively large considering the fact that the variation in the simulated input ground motion records was rather small. This shows the importance of incorporation in the damage-involved numerical analysis the effects connected with propagation of the seismic wave.
Corrosion Behavior of a WC/C Coated 7075-T6 Aluminum Alloy
Authors: Baragetti Sergio , Daurù M. , Gerosa Riccardo , Rivolta Barbara
Published: September 2013

In the present experimental work, a WC/C coated 7075-T6 aluminum alloy was considered from the corrosion point of view. The coating was deposited by PVD technique with a final thickness of about 2.5μm. In order to study the influence of the coating on the corrosion behavior of the aluminum alloy, the samples surfaces were partially coated and the interface among the metal and the coating was analyzed after the corrosion tests described into the ASTM G110 standard. Such experimental plan was decided in order to simulate the possible in-service local removal of the thin and hard coating. This kind of damage, due for example to a foreign object impact, can occur because of the great hardness difference between the coating and the substrate. The experimental tests were carried out on samples with different surface finishing, ranging from about 0.02μm Ra (mirror-polished surface) to about 0.8μm Ra (320 grit paper). The aim of such choice was to investigate the effect of a surface roughness different from the optimal one (mirror polished) on the coating deposition. Moreover a different corrosion resistance is expected.
Evaluation of Elastic Properties of Satin Composites
Authors: Patel S. , Bacarreza Omar , M.H.Aliabadi Ferri
Published: September 2013

Advancements in the numerical modelling of 3D woven composites have allowed improved understanding of the mechanical behaviour and in turn aided the design and analysis of new materials. The objectives of this paper are to utilise FEA (Finite Element Analysis) methods to determine the elastic properties of a given woven composite. The investigation focuses on satin weaves, considering both 5-harness and 8-harness varieties. Multi-scale analysis results of an RVE are used to formulate the stiffness matrix and consequently determine the elastic properties; these will be compared to published analytical methods and experimental results. Further investigations considering the effect of weave parameters on the elastic properties are conducted.
Computational Modelling of Brittle Failure in Polycrystalline Materials Using Cohesive-Frictional Grain-Boundary Elements
Authors: Benedetti Ivano , M.H.Aliabadi Ferri
Published: September 2013

A 3D grain-level formulation for the study of brittle failure in polycrystalline microstructures is presented. The microstructure is represented as a Voronoi tessellation and the boundary element method is used to model each crystal of the aggregate. The continuity of the aggregate is enforced through suitable conditions at the intergranular interfaces. The grain-boundary model takes into account the onset and evolution of damage by means of an irreversible linear cohesive law, able to address mixed-mode failure conditions. Upon interface failure, a non-linear frictional contact analysis is introduced for addressing the contact between micro-crack surfaces. An incremental-iterative algorithm is used for tracking the micro-degradation and cracking evolution. A numerical test shows the capability of the formulation.
Application of Ductile Damage Concepts in the Evaluation of Material Formability during Screw Head Cold Forming
Authors: Coppola Tommaso , Cortese L. , Guarnaschelli Claudio , Salvatori I.
Published: September 2013

An up to date approach to material cold formability, based on a conventional J2 theory for plasticity together an uncoupled linear plastic damage evolution theory, is applied to the study of steel bolt head cold forming. Specific laboratory tests to characterize the material formability have been used. Finite element simulations have been performed to characterize the strain and stress state both in the forming process and in experimental tests to determine the material ductile fracture locus. The influence of chemical composition and initial microstructure is discussed.