bluuebunny/crossref_metadata_2025 huggingface dataset:
An Approach of Aerial Photogrammetry Measurement Based on 3D Model
Authors: Cui Yi , Zhao Xian , Jing Chang Feng
Published: February 2012

.This paper introduces a new approach on measurement of aerial photogrammetry. Because of the development of stereoscopic display technology, the author wants to change 2D working environment to 3D working environment during aerial photogrammetry measuring process. The approach gives a new way to do aerial photogrammetry measurement in 3D environment. Firstly, we made image pixel data one-to-one corresponding with DEM data of the area. Then, we built a 3D model of the area. Since the one-to-one corresponding of DEM and image, we obtained photo coordinates of the target points of stereo pair on left image and right image in single click. And then, with the help of traditional theory， we finished calculation of the transforming from photo coordinate system to ground coordinate system, by which we could obtain ground coordinates of the target points. Finally, we overlapped the points which we calculated on the DLG in ArcGIS software to validate the correction of the calculation. The result shows that the precise of this approach is acceptable. At the end of the paper, the author gave some advices to improve the approach and the expectation of 3D measurement in true 3D environment.
A Kind of Multi-Channel Filtering Based Wavelet Packet Remote Sensing Image Fusion
Authors: Dong Su Rong , Zhou Hai Ying
Published: February 2012

A kind of multi-scaled texture feature based wavelet packet fusion approach be presented, which applies the principle of multi-channel filtering fusion to take wavelet fusion on the image with aplenty scaled texture feature and the multispectral image, meanwhile, for obtaining diversified scaled texture feature information and high resolution image, a regional characteristics based self-adapted wavelet packet fusion criteria be proposed. The experiment result and statistics analysis shows that the improved wavelet packet algorithm get the relatively improvement in the aspects of information amount and the clarity comparing with the traditional wavelet packet fusion.
The Use of Vacuum Deposition for Fabrication of Optical Amplifying Mediums and Fiber Optic Modules
Authors: Elchiev Javlon D. , Djalalov Muzaffar M. , Simonov Aleksandr A.
Published: February 2012

There has shown new vacuum technique of making planar waveguides doped with rare earths, on the basis of simultaneous vacuum deposition of quartz and alloying components. This technology allows to create optical waveguiding layers and amplifying planar compositions on wafers of silicon or quartz, and allows the dose-doping quartz with rare-earth elements, as well as germanium oxide and aluminum oxide, to obtain the optimal composition of a planar waveguide. With the help of lithography formed planar guide mediums with amplifying and modulating properties. There have been researched the methods of production of laboratory models of optical amplifying mediums, using vacuum technology, for the manufacture of planar erbium-doped amplifiers.
Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding
Authors: Bian Zhi , Xie Peng Cheng , Ding Yu Mei , Yang Wei Min
Published: February 2012

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically signiﬁcant main and two-factor interaction effects, the results showed that the supercritical ﬂuid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.
Preparation of Porous Polysulfone Membranes Using Ionic Liquids with Different Alkyl Chain as Additives
Authors: Zhao Ya Mei , Zheng Chang Zheng
Published: February 2012

1-alky-3-methylimidazolium hexfluorophosphate ([n-Cnmim][PF6]) and 1-alky-3- methylimidazolium thiocyanate ([n-Cnmim]SCN) (n=4,8,16) were firstly introducing into the casting solution (PSF/NMP), porous polysulfone (PSF) membranes were successfully prepared by the wet-phase-inversion. The scanning electron microscope was utilized to visualize the cross-sections of the membranes, in order to study the influence of ionic liquids with different alkyl chain on the porous structures. The results indicate that the PSF membranes have different structures and separation properties due to ionic liquids with different alky chain. For ionic liquids with the short alkyl chain, the prepared membranes have the porous structure on cross-sections, but no or weak separation properties. However, for ionic liquids with the long alkyl chain, the prepared membranes have both porous structure and good separation properties. According to the structure of a hydrophobic straight-long alkyl and a hydrophilic limidazolium ring, the ionic liquid with long alkyl chain is considered as a surfactant, it can change not only the interface properties between the casting solution and coagulation bath, but also induce the space structures of the polymer chains.
Study on Curing Process of Resin Nanocomposites
Authors: Wang Chuan Sheng , Wang Rui Qin , Wang Yuan , Fu Yong Xiang
Published: February 2012

In order to get an optimum performance of composite materials, it is of crucial importance to select the best curing process, on condition that resin and curing agent system is determined. In this paper, we studied the curing non-isothermal dynamics of the nmSi02 / epoxy resin system, and calculated the activation energy and reaction series, according to Kissinger, Ozawa and Crane method. We found out the peak temperature, the theory gel temperature and the theory curing temperature with extrapolation as heating rate β= 0. Finally we determined the best curing process range of the system.
Analysis of the Impact of Unloaded Radius of Tire on the Handling and Stability of Automobile on the Basis of ADAMS/CAR
Authors: Wang Ze Peng , Cui Wen Liang , Yu Zhen
Published: February 2012

Because the brake and turn of automobile is completed by transmitting the force and torque to the ground through the tire, tires can influence the handling and stability of automobile. The impact of the unloaded radius of tire on the handling and stability of automobile was studied on the basis of ADAMS/CAR in this paper. The unloaded radius of tire was only changed and other parameters remain unchanged, then full vehicle analysis was carried out to get the simulation curves. The impact of the unloaded radius of tires on the handling and stability of automobile was obtained from the curve of simulation. The results of simulation are conducive to designing the shape and dimension of tires.
Experimental Study on Effects of Filling Factor and Polyester Short Fiber Addition on Mixing of Short Fiber-Rubber Composite Material
Authors: Zeng Xian Kui , Zhang De Wei , Wang Chuan Sheng , Bian Hui Guang
Published: February 2012

Filling factor and polyester short fiber addition impact the mixing process and performances of mixed rubber greatly. The effects of filling factor and polyester short fiber addition on mixing short fiber-rubber composite material have been studied by experimental study. And according to the experimental results, at the condition of filling factor was 0.6 and polyester short fiber addition was 3, the performances of mixed rubber were best.
Optimization of Vertical Slab of Screw Tire-Shaping Vulcanizing Machine Based on FEM
Authors: Wang Zhi Qiang , Fan Yan Jun , Lv Bai Yuan
Published: February 2012

This paper, after optimization of the vertical slab in screw tire-shaping vulcanizing machine taking the method of FEM, shows that the stiffener-inside slab is better than the stiffener-outside, the slab with the structure of stiffeners is better than the bare-board one. Meanwhile, it cuts about 23.69% cost of the steel to take the optimized scheme.
Heat Transfer and Friction Characteristics Analyses between WPC Materials and Conveyor Plate
Authors: Tang Yue , Tu Wen Min
Published: February 2012

Through experiments to measure the warming time of top and bottom surfaces of the conveyor plate at different heating temperature, the difference in temperature of top and bottom surfaces was used to analyse the heat transfer characteristics of conveyor plate. And the static difference in temperature heat transfer rate was used to reflect difficulty level of the conveyor plate top and bottom surfaces temperatures close to each other. The solid transportation effect of the wood powder and PVC mixture was confirmed to be best, and the best drying and transferring temperature should be around 80 °C.
Simulation of a Closed-Loops Assembly Line
Authors: Ferreira L.P. , Ares E. , Peláez G. , Resano A. , Luis-Pérez C.J. , Tjahjono B.
Published: February 2012

The aim of the work presented in this paper describes the development of a decision support system based on a discrete-event simulation model of an automobile assembly line. The model focuses at a very specific class of production lines with a four closed-loop network configuration. One key characteristic in the closed-loop system is that the number of pallets inside the first three loops has been made constant. The impact of the number of pallets circulating on the first three closed-loops and of the proportion of four-door car bodies on the performance of the production line has been thoroughly investigated. This has been translated into the number of cars produced per hour, in order to improve the availability of the entire manufacturing system.
MEMS Bionic Vector Hydrophone
Authors: Zhang Guo Jun , Xue Chen Yang , Xiong Ji Jun , Zhang Wen Dong , Wang Xiao Yao , Liu Lin Xian , Ge Xiao Yang
Published: February 2012

A novel MEMS vector hydrophone with bionics structure was introduced in 2007. As the acoustic-electric transducer infrastructure has been optimized, the performance of the hydrophone has been greatly improved compared with the previous. This hydrophone calibration was finished in National Defense Underwater Acoustics Calibration Laboratory of China. According to test results, the sensitivity of the hydrophone is -165dB（including pre-amplification 20 dB）,The frequency response ranges from 20Hz to 2kHz (±5dB). And this hydrophone has a good directional pattern in form of "8"-shape.
Quadrature Error and Offset Error Suppression Methods for Micro-Gyroscopes
Authors: Mo Bing , Zhou Huo , Zheng Qi , Chen Si Hao , Ling Chao Dong
Published: February 2012

Because of the imperfections of the manufacture, the quadrature and offset error become the major concerns in Micro-gyroscopes for high performance. So in order to eliminate and minimize quadrature and offset error, various methods employing improvement of manufacture and suppression circuitry have been put forward to improve the performance. And this paper summarize most of the suppression methods those who have better performance.
Optimal Design and Simulation of a Cross-Plane Micro-Thermoelectric Generator
Authors: Zhu Xiao Liang , Li De Sheng , Liu Ben Dong , Zhe Jiang
Published: February 2012

This paper presents a new way to design a low-cost micro-thermoelectric generator (μ-TEG) which can be fabricated by using electrochemical and MEMS technology. The overall dimension of the μ-TEG is about 13mm × 13mm × 0.4mm, which contains 128 p- and n-type pairs of semiconductors connected electrically in series and thermally in parallel. The p-type antimony telluride (Sb2Te3) and n-type bismuth telluride (Bi2Te3) with an optimal thickness of 20μm were designed to deposit in a flexible polymer mold formed by photolithographic patterning of Polyimide (PI) with a three electrode configuration. Simulations of the thermocouple with PI mold were carried on, using finite element analysis. The analysis shows the possibility to achieve 3.5 mV while the difference in temperature is 10K and the thickness of the silicon substrate is 400μm, which reveals that the output power of the thermocouple without releasing process is only 4% lower than the one with the releasing process. Therefore the PI mold is not removed, considering the potential for easier fabrication and lower cost. The deposition parameters were also studied and optimized for the best thermoelectric performance. In our experiments, the n- and p-type semiconductors could be obtained when the voltage and current are around 50mV versus saturated calomel electrode (SCE) and 40 mA, respectively.
Simulation on S Parameter of an X-Band Wilkinson Power Divider
Authors: Liu He Chao , Liao Xiao Ping
Published: February 2012

This paper describes analysis of the S parameter of an X-band (8-12GHz) Wilkinson power divider by using odd-even mode, as well as full circuit analysis technique. The closed-form model of the S parameters versus normalized frequency response of the power divider is proposed for the first time according to our acknowledgement. The expressions are compared with the results obtained from a full-wave electromagnetic simulator (ADS) and found to yield acceptable agreement: the insertion loss is -3dB, the maximum difference of return loss of port 1 and isolation is about 0.17dB, the return loss of port 2 is less than -38dB.
Application of ICP Deep Trenches Etching in the Fabrication of FBAR Devices
Authors: Shang Zheng Guo , Li Dong Ling , Wang Sheng Qiang , Liu Jian Hua
Published: February 2012

It is presented a fabrication processing of a two step method in deep silicon etching for MEMS applications using an the UK company Surface Technology Systems plc (STS), inductively-coupled plasma (ICP) etch technique STS ICP deep dry etching system. A brief introduction of schematic process of etching deep trenches on silicon substrate is first given, then with two step method for etching deep trenches. The film bulk acoustic resonator (FBAR) devices have been fabricated using STS ICP deep dry etching system with maximum etch rate of 4.6μ m/min, depth more than 450μm and sidewall roughness no more than 0.14μm. At the end of the second step process, the etch selective ratio of silicon to silicon oxygen is enhanced to ensure the device yield. At the same time, the negative effects such as microloads effects, footing effects, lag effects and micrograss effects are suppressed effectively.
Design of a Digital Decimation Filter for High-Precision 4-Order Sigma-Delta ADC
Authors: Chen Wei Ping , Fu Qiang , Liu Xiao Wei , Xiao Yan , Zhang Bin , Yang Yu Heng
Published: February 2012

In this paper, a design of a digital decimation filter which has a output of 24 bits for high-precision 4-ordes Σ-Δ ADC is proposed. The digital decimation filter includes a CIC filter, a compensation filter and a half band filter. The over-sampling rate of the digital decimation filter is 256, the cutoff frequency is 1kHz, the coefficient of the pass-band ripple is -0.25dB, the stop-band attenuation is -162dB, simulation results using Matlab and modelsim are correct, the result of the FPGA verification shows that the design meet the requirement of the high-precision 4-ordes Σ-Δ ADC.
Optimal Design of Micro Plastic Heat Radiator
Authors: Han Yue , Zhang Ya Jun , Wu Da Ming , Zhuang Jian , Dang Kai Fang
Published: February 2012

A new type of plastic micro heat radiators is designed in this paper. The radiator is prospected to be used in electronic system, chemical engineering system, etc. It is made of modified Phenylene sulfide with high thermal conductivity. A series of numerical simulations are carried out to optimize the structure of the radiator. The structure of the radiator includes the thickness of the fin and the distance between fins. The results show that the performance of the micro plastic heat radiator is very close to that of the metal heat radiator with the same dimension.
Simulation of Characteristic of a Thermoelectric Power Sensor Based on MEMS Technology
Authors: Liu Tong , Liao Xiao Ping
Published: February 2012

A thermal equivalent model based on Fourier equation is introduced to optimize a thermoelectric microwave power sensor in this paper. The different distance between the load resistor and thermopile is considered carefully to obtain good matching characteristic and high sensitivity characteristic. The sensitivity of the thermoelectric power sensor has been chosen as a goal function with the distance, the length of thermopile and the number of thermopiles as independent variables. The simulation results show that the sensitivity of the power sensor decreases with the distance, but increases with the length and the number of thermopiles. Then the input matching characteristic of this thermoelectric power sensor with different distance are simulated with HFSS. The power sensor has a good performance on sensitivity characteristic and input match characteristic with an optimization distance is about 10μm.
Phase Transition Characterization Dependent on Temperature and DC Electric Field for (Pb, La) (Zr, Ti)O3 Antiferroelectric Thick Films
Authors: Chou Xiu Jian , Du Miao Xuan , Lv Yong Bo , Liu Jun , Zhang Wen Dong
Published: February 2012

Pb0.97La0.02(Zr0.95Ti0.05)O3 antiferroelectric thick films were prepared on platinized silicon substrates by sol–gel methods. Films showed polycrystalline perovskite structure with a strong (100) preferred orientation. The antiferroelectric nature of the films was confirmed by the double hysteresis behaviors versus applied field. The temperature dependence of dielectric constant and loss displayed the Curie temperature was 225oC.The current caused by the polarization and depolarization of polar was detected at coupling application of electric field and temperature. The phase transition characterization could be effectively adjusted by electric field and temperature.
Material Characterization for Sheet-Bulk Metal Forming
Authors: Behrens Bernd-Arno , Voges-Schwieger Kathrin , Bouguecha Anas , Mielke Jens , Vucetic Milan
Published: February 2012

Sheet-bulk metal forming is a novel manufacturing technology, which unites the advantages and design solutions of sheet metal and bulk metal forming. To challenge the high forming force the process is superimposed with an oscillation in the main flow of the process. The paper focuses on the characterization of the material behavior under cyclic load and the effects for the sheet bulk metal forming process.
Metallurgical Model Fitted to Experimental Data Using a Genetic Algorithm
Authors: Blaise Alexandre , Bourouga Brahim , Dessain Christine
Published: February 2012

The hot stamping process is an established process in the automotive industry to satisfy challenges concerning security aspects and lightweight construction. Now, innovative processes have arisen which consist in heating locally the tools and thus adjust local final mechanical properties of the parts. To simulate accurately this so called tailored tempering process, a coupling between thermal and metallurgical phenomena must be considered as the metallurgical transformations lead to a source term in the heat equation and the thermal evolution drives the transformation. To improve the model, a genetic algorithm optimizes the metallurgical model parameters to fit both the CCT and TTT diagrams, taking in account the cooling rate dependence. This method for creating a metallurgical data file, that is directly usable by the industrial software and that fits the TTT diagram and the final constituent proportions of the different constituents, is presented. This method, tested on hypothetical experimental data, is then validated and results are presented. Moreover, the principle of this work can be adapted to various softwares that industries use.
Optimization of the Incident IR Heat Flux upon a 3D Geometry Composite Part (Carbon/Epoxy)
Authors: Nakouzi S. , Berthet F. , Delaunay D. , Le Maoult Y. , Schmidt Fabrice , Sobotka Vincent
Published: February 2012

The main purpose of this study is to cure a 3D geometry composite part (carbon fiber reinforced epoxy matrix) using an infrared oven. The work consists of two parts. In the first part, a FE thermal model was developed, for the prediction of the infrared incident heat flux on the top surface of the composite during the curing process. This model was validated using a reference solution based on ray tracing algorithms developed in Matlab®. Through the FE thermal model, an optimization study on the percentage power of each infrared heater is performed in order to optimize the incident IR heat flux uniformity on the composite. This optimization is performed using the Matlab® optimization algorithms based on Sequential Quadratic Programming and dynamically linked with the FE software COMSOL Multiphysics®. In a second part, the optimized parameters set is used in a model developed for the thermo-kinetic simulations of the composite IR curing process and the predictions of the degree of cure and temperature distribution in the composite part during the curing process.
Numerical Simulation of the Viscohyperelastic Behaviour of PET near the Glass Transition Temperature
Authors: Luo Yun Mei , Chevalier Luc , Monteiro Eric
Published: February 2012

The presentation deals with the non linear strongly elastic and viscous behaviour of poly ethylene terephthalate near the glass transition temperature and biaxially stretched at high strain rates representative of the injection stretch blow moulding process. A non linear visco-hyperelastic model inspired from [1] and identified from the experimental results of the equi-biaxial tension test [2], have been developed and presented in [3] is implemented into a finite element code developed with Matlab. The thermal behaviour modelling, identification and simulation has also been managed. First, a numerical simulation of 2D plane stress case has been performed involving 2 fields (global velocity V and elastic Cauchy Green tensor Be). Rectangular finite elements with quadratic and linear interpolations have been employed for velocity and the elastic left Cauchy Green tensor. Second, an axi symmetric formulation involving 4 fields (global velocity V, lagrange multiplier p associated with the global incompressibility condition, and multiplier q associated with the incompressibility of the elastic part) has been performed using rectangular elements. Degree of interpolation have been tested for all possible combinations to test the LBB like condition. Both simulations are compared with equi biaxial or sequential biaxial testing in order to reproduce the strain hardening effect and the self-heating observed. The final goal of this work is to perform the free blowing simulation to compare with experimental data. Therefore, we should solve an iterative procedure for a thermo-mechanical equation. At each time step, a four-field approach is adopted for the mechanical part, and a classical heat transfer equation is discretised for the thermal part.
Microstructural Modification of Laser-Bent Open-Cell Aluminum Foams
Authors: Santo Loredana , Bellisario Denise , Rovatti Ludovica , Quadrini Fabrizio
Published: February 2012

Laser forming tests have been performed on open-cell aluminum alloy foams with different pore size. Laser power was fixed at 150 W, a total of 150 laser scans led to a bending angle up to 60°, depending on the laser scan rate. At the end of the laser bending, the foams were left to cool and samples were extracted for analysis by means of an optic microscope. The alloy microstructure was investigated in different points of the samples and correlated with the processing conditions. Image analysis was also carried out to extract the percentage of melted area due to laser heating.
Characterization of Friction Modified Processing – A Novel Tool for Enhancing Surface Properties in Cast Aluminium Alloys
Authors: Weglowski Marek S. , Pietras Adam , Dymek Stanisław , Hamilton Carter
Published: February 2012

Friction Modified Processing (FMP) is a novel solid state processing technique which can be used for microstructural modification of surface layers in metallic materials. The paper deals with the investigation of the influence of process parameters on the microstructure in the surface layer of a cast aluminum alloy. The FMP was conducted on a constructed welding machine equipped with appropriate devices (LOWSTIR and TermSTIR). The measurements of temperature in the stir zone were compared with a numerical model. Another model was developed to determine the quantitative relationships between mass of modified material and processing speeds over a wide experimental range. An exponential formula has been found to describe the relationship between mass of modified material and rotational speed. The evaluation of the traveling speed affecting the mass of the modified material was successfully approximated by linear functions.
Dynamic Simulation of the Micro-Milling Process Including Minimum Chip Thickness and Size Effect
Authors: Ducobu François , Rivière-Lorphèvre Edouard , Filippi Enrico
Published: February 2012

Micro-milling with a cutting tool is a manufacturing technique that allows production of parts ranging from several millimeters to several micrometers. The technique is based on a downscaling of macroscopic milling process. Micro-milling is one of the most effective process to produce complex three-dimensional micro-parts, including sharp edges and with a good surface quality. Reducing the dimensions of the cutter and the cutting conditions requires taking into account physical phenomena that can be neglected in macro-milling. These phenomena include a size effect (nonlinear rising of specific cutting force when chip thickness decreases), the minimum chip thickness (under a given dimension, no chip can be machined) and the heterogeneity of the material (the size of the grains composing the material is significant as compared to the dimension of the chip). The aim of this paper is to introduce some phenomena, appearing in micromilling, in the mechanistic dynamic simulation software ‘dystamill’ developed for macro-milling. The software is able to simulate the cutting forces, the dynamic behavior of the tool and the workpiece and the kinematic surface finish in 2D1/2 milling operation (slotting, face milling, shoulder milling,…). It can be used to predict chatter-free cutting condition for example. The mechanistic model of the cutting forces is deduced from the local FEM simulation of orthogonal cutting. This FEM model uses the commercial software ABAQUS and is able to simulate chip formation and cutting forces in an orthogonal cutting test. This model is able to reproduce physical phenomena in macro cutting conditions (including segmented chip) as well as specific phenomena in micro cutting conditions (minimum chip thickness and size effect). The minimum chip thickness is also taken into account by the global model. The results of simulation for the machining of titanium alloy Ti6Al4V under macro and micro milling condition with the mechanistic model are presented discussed. This approach connects together local machining simulation and global models.
Cutting Speed-Feed Based Parametric Model for Macro-Geometrical Deviations in the Dry Turning of UNS A92024 Al-Cu Alloys
Authors: Sánchez-Sola José Miguel , Batista Moises , Salguero Gómez Jorge , Gómez-Parra Álvaro , Marcos Bárcena Mariano
Published: February 2012

This work reports on the results of a study of different macro-geometrical deviation parameters, such as Straightness (SD), Parallelism (PD) and Circularity (CD) as a function of cutting speed (v) and feed (f) of dry turned UNS A92024 (Al-Cu) cylindrical bars. The results obtained have allowed establishing exponentials parametric model for predicting these deviations as a function of those cutting parameters. As a consequence of that, geometrical surfaces SD(f,v), PD(f,v) and CD(f,v) have been developed for this alloy. These surfaces allows determining marginal curves for specific v and f values, respectively, out the parameter ranges employed. So, macro-geometrical deviations can be predicted through this model for v and f values out of those considered in the study for each alloys.
Development of a Calorimeter to Determine the Chip Heat in Drilling of C45EN
Authors: Denkena Berend , Ammermann Christoph , Niederwestberg Daniel
Published: February 2012

This study is focused on developing and testing a calorimeter to measure the chip heat in drilling of C45EN. Inside the calorimeter, the cut chips fall into a fluid with known heat capacity. Its temperature is measured continuously with thermocouples. Based on calorimeter designs found in the literature, the principal assembly of the calorimeter was adapted to be used in drilling and to minimize heat losses. A modular design with measuring box, process box and top cover was developed. This allows a smooth handling of the calorimeter during experiments as well as the use of the calorimeter to analyze further processes like milling. A horizontal configuration of workpiece and tool was chosen to optimize the chip fall into the fluid, which is a basic requirement for measuring the exact temperature of the chips. The temperature is measured by three thermocouples at different positions of the calorimeter to quantify the temperature distribution in the fluid. To accelerate the process of thermal balance between chip and fluid, the system was dynamically stimulated by jerky movements of the machine axes. This aims to a uniform distribution of the chips within the calorimeter. First experimental tests validated the functionality of the calorimeter and demonstrated that dynamic axes movements accelerate the heat transfer from chip to the fluid substantially.
Design an Apparatus for Obtaining to High Precision Surface of Miniature Parts Based on Magnetized Abrasive Grains Finishing Process
Authors: Montazerolghaem Hamid , Soltani Esmaeil
Published: February 2012

Obtaining to high quality surfaces of industrial parts is an important manner for manufacturing involves. Different finishing process are capable to providing the require surface roughness in most cases, considering that, in some special parts, depending on shape, material and dimension of parts, the prevalent methods are limited, especially in finishing of sculptural and curvilinear surfaces. In this research, a new applied apparatus is represented based on magnetized abrasive grains finishing process. In this way, abrasive grains gathering around a rotational cylindrical tool thanks to a permanent magnetic field and work-piece, which usually is a formed thin metal sheet, located on a rotary table. Therefore, coinciding of those motions providing the require machining forces for finishing of surface without any physical contact between tool and work-piece. Presented process may carry out dry and wet in case of changing the main machining parameters such as: material and size of abrasive grains, tool and work-piece surface gap distance, tool and/or table rotational speed (r.p.m) and work-piece material. The recommended process has remarkable advantages such as: non-contact surface finishing, high finishing of non-flat surfaces, no need to clamping for work-piece because of low machining forces, responsibility for finishing of a wide range of materials except magnetizable parts, low machining costs and easy set up. This method has a lot of applications in production of optical lens, orthopedic prosthetic components and jewellery. For approve of the designed apparatus advantages, relative to other existed MR fluid machining system, some samples of very thin complex formed sheet have been successfully polished.
EcoForge: Resource-Efficient Process Chains for High Performance Parts
Authors: Behrens Bernd-Arno , Bleck Wolfgang , Bach F.W. , Brinksmeier E. , Fritsching U. , Liewald Mathias , Zoch H.W.
Published: February 2012

Classical forging process chains for the production of high performance parts consist of heating, hot forming, machining and heat treatment stages. Especially the last stage comprises numerous energy consumptive heating and cooling procedures. Consolidation of these process chains has a large energy-saving potential and thus can lead to ecological and economic advantages. In addition, the optimization may result in well enhanced local material properties in the final part. Therefore, the collaborative research project “EcoForge: Resource-efficient process chains for high performance parts” has been initiated. Five renowned research institutes aim at optimising the industrially relevant process chain in order to facilitate the resource-efficient production of forgings with increased load bearing capacity. The six subprojects of EcoForge include both, numerical investigations on the microstructure evolution and cooling behaviour of the forged parts as well as numerous experiments which will be carried out in collaboration with the project’s industrial consulting committee, summarising up to 50 relevant participating companies. The joint project is funded by the AiF and BMWi aiming at major areas of technical developments in Germany.
Numerical and Experimental Investigations on the Service Life Estimation for Hot-Forging Dies
Authors: Behrens Bernd-Arno , Bouguecha Anas , Hadifi Tarik , Klassen Andreas
Published: February 2012

Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element method (FEM) may serve as a means for process design and process optimisation. So far the FEM based estimation of the production cycles until initial cracking is limited as tool material behaviour due to repeated loading is not captured with the required accuracy. Material models which are able to account for cyclic effects are not verified for the fatigue life predictions of forging dies. Furthermore fatigue properties from strain controlled fatigue tests of relevant hot work steels are to date not available to allow for a close-to-reality fatigue life prediction. An industrial forging process, where clear fatigue crack initiation has been observed is considered for a fatigue analysis. For this purpose the relevant tool component is modelled with elasto-plastic material behaviour. The predi
Cross Wedge Rolling of Preforms for Crankshafts
Authors: Meyer Matthias , Stonis Malte , Behrens Bernd Arno
Published: February 2012

To produce preforms for complex long flat parts with an unsteady mass distribution along the longitudinal axis rolling processes, like cross wedge rolling, can be used. Tools for cross wedge rolling processes can be constructed as roller or flat, both with wedges. In the collaborative research project SFB 489 “Process chain for the production of precision forged high performance parts” the subproject “Innovative machine and tool technology for precision forging” deals with the development of a flashless forging process for a two cylinder crankshaft with pin and flange. This process is developed by IPH – Institut für Integrierte Produktion Hannover. The first preform of the developed forging sequence is produced by a cross wedge rolling process on the basis of flat with wedges. To consider the mass distribution of the two cylinder crankshaft in the preform for a rolling process four mass concentrations for the crank arms and mass concentrations for pin and flange are needed.
Analysis of the Anisotropic Behavior and of the Formability Aptitude for an AA2024 Alloy Using the Channel Die Compression Test and the Simple Tension Test
Authors: Zhang Shun Ying , Francillette Henri , Gavrus Adinel
Published: February 2012

The mechanical behavior of metallic materials during sheet forming processes must be related to their anisotropic properties and their formability aptitude. So, in this paper, channel die compression experiments are proposed to analyze the anisotropy of an AA2024 thick sheet. A modified quadratic Hill criterion based on the variation of the coefficients with the cumulated plastic strain is proposed. To compare and to validate the identified Hill coefficients values, classical tensile tests are also analyzed. The results are validated via finite element simulations of the tensile tests and channel die compression experiments using the commercial code LS-DYNA.
Intraply Shearing Characterization of Thermoplastic Composite Materials in Thermoforming Processes
Authors: Wang Peng , Hamila Nahiene , Boisse Philippe
Published: February 2012

The Continuous Fibre Reinforcements and Thermoplastic resin (CFRTP) are widely employed in the prepreg processes. Currently, the most used thermoplastic resins in aeronautics are PPS (polyphenylene sulfide) and PEEK (Polyetheretherketone). They present many advantages on their mechanical properties. However, these mechanical properties depend strongly upon the thermoforming conditions, especially the intraply shearing. In order to improve and complete the understanding about the in-plane shear behavior of thermoplastic composite materials in their forming processes, the thermo-mechanical analysis of PPS/carbon and PEEK/carbon commingled fabrics at different forming temperatures are performed by using the bias-extension tests. The experimental data leads to significant difference on the in-plane shear behavior under different temperature, as well as the wrinkles can be noted in certain thermoforming conditions. Therefore, in order to predict the feasible forming conditions and optimize the important forming parameters of the thermoplastic composites, the in-plan shear behaviors in function of temperature will be integrated into our numerical model to carry out the numerical simulations of thermoforming processes.
Simulating the Manufacturing Process and Subsequent Structural Stiffness of Composite Wind Turbine Blades with and without Defects
Authors: Fetfatsidis Konstantine A. , Mitchell Cynthia , Sherwood James A. , Harvey Eric , Avitabile Peter
Published: February 2012

Traditional ply-based and zone-based models are limited in their ability to account for the fiber directions resulting from the forming of fabric-reinforced composite wind turbine blades. Compounding the problem is the presence of defects such as resin-rich pockets of the polymer matrix due to out-of-plane and in-plane waves resulting from the manufacturing process. As a result, blades are typically overdesigned, unnecessarily increasing weight and material costs. In the current research, a methodology is presented for simulating the manufacturing process for fabric-reinforced composite wind turbine blades using ABAQUS/Explicit. The methodology captures the evolution of the yarn directions during the forming process thereby allowing for a map of the fiber orientations throughout the blade. A hybrid approach using conventional beam and shell elements is used to model the various fabric layers. Using experimental shear, tensile, bending, and friction data to characterize the mechanical behavior of the fabric layers, the model captures in-plane yarn waviness and changes in the in-plane yarn orientations as they conform to the shape of the mold, as well as out-of-plane wave defects as a result of the manufacturing process. Subsequently, after the fabric layers have been laid into the mold and the final yarn orientations are known, the structural stiffness of the blade resulting from the resin-infused fabrics can be calculated. The methodology can thereby link the resulting bending and torsional stiffnesses of the blade back to the manufacturing process. This paper discusses the methodology for determining the material properties of the beam and shell elements in their final orientations in the cured composite to predict the structural stiffness of a wind turbine blade.
Tow-Scale Mechanics for Composite Forming Simulations
Authors: POTLURI Prasad , Ramgulam Raj , Chilo Marco , Arshad Haseeb
Published: February 2012

Abstract. Composites are processed by a variety of forming techniques at both preforming and consolidation stages; ranging from hand draping, diaphragm forming, vacuum infusion to Resin Transfer Molding. During these processes, individual fabric or prepreg layers are subjected to inplane tension and shear, inter-ply shear, transverse compression and out-of-plane bending forces. These forming forces are translated into individual tow-level forces leading to tow deformations. Each tow is subjected to tension, transverse compaction (in the plane of the fabric due to shear and normal to the fabric plane due to consolidation force), bending and torsion. The resulting tow geometry and local fibre volume fractions (within a tow) would have a significant impact on resin flow as well as mechanical properties of the composite. In this paper, we present computational as well as experimental approaches to predicting tow deformations, when subjected to various loading conditions. The test rigs, shown in figure 1, can measure stress-strain behaviour of a tow in bending, torsion and transverse compression respectively. Figure shows buckling of carbon tow – bending stiffness can be computed from the post-buckling behavior. Torsional moments at monotonically increased twist angle were measured using a very sensitive torque sensor. An anvil, nearly same size as a tow, is used to compress a tow (under controlled axial tension) and the cross-sectional shape is computed from the flattened image (recorded using a high resolution camera). A mechanics-based model has been developed to predict tow-scale deformations under transverse compression, tension, bending and torsion modes of deformation. Individual fibres in a tow are modeled as ‘3D elastica’ and a simple inter-fibre friction model has been incorporated. Initially developed for twisted fibre bundles, the elastic-based model works reasonably well for untwisted fibre tows (by assuming an extremely small twist level for convergence). Full paper will present comparison between experimental and theoretical results.
Tow Mechanics: A Contact Mechanics Approach of Friction in Fibrous Tows during Forming
Authors: Cornelissen Bo , Rietman Bert , de Rooij Matthijn , Akkerman Remko
Published: February 2012

Composites forming processes involve mechanical interactions on the ply, tow, and filament level. The deformations that occur during forming processes are governed by friction between tows and tooling material on the mesoscopic level and consequently between filaments within the tows on the microscopic level. A thorough understanding of the frictional properties of individual filaments is essential to understand and to predict the macroscopic deformations of a fabric during forming. This paper provides a global description of the experimental and modelling approaches to explain the contact friction between fibrous tows and metal tooling material, focusing on contact mechanics at the tow and filament scale.
Plastic Instability Based on Bifurcation Analysis: Effect of Hardening and Gurson Damage Parameters on Strain Localization
Authors: Mansouri Lotfi Zoher , Chalal Hocine , Abed-Meraim Farid , Balan Tudor
Published: February 2012

Strain localization, which occurs in metallic materials in the form of shear bands during forming processes, is one of the major causes of defective parts produced in the industry. Various instability criteria have been developed in the literature to predict the occurrence of these plastic instabilities. In this work, we propose to couple a GTN-type model [1,2], known for its widespread use to describe damage evolution in metallic materials, to the Rice’s [3] localization criterion. The implementation of the constitutive modeling is achieved via a user material (UMAT) subroutine in the commercial finite element code ABAQUS. Large deformations are taken into account within a three dimensional co-rotational framework. The effectiveness of the proposed coupling for the prediction of the formability of stretched metal sheets is shown and Forming Limit Diagrams (FLDs) are plotted for different materials. References [1] Gurson, A.L., Continuum theory of ductile rupture by void nucleation and growth: Part I- yield criteria and flow rules for porous ductile media. Journal of Engineering Materials and Technology, 99(1):2–15 (1977). [2] Needleman A., V. Tvergaard, An analysis of ductile rupture in notched bars, Journal of the Mechanics and Physics of Solids, 32, 461-490 (1984). [3] Rice, J. R., The localization of plastic deformation. Theoretical and applied mechanics. Koiter ed., 207-227 (1976).
Numerical Modelling and Experimental Study of Sandwich Shells with Metal Foam Cores
Authors: Mata Helder , Natal Jorge R. , Santos A.D. , Parente M.P.L. , Valente Robertt , Fernandes A.A.
Published: February 2012

The trends in automobile industry always include the use of new materials such as those needed for the passive safety of vehicles and they are one of the most important strategies to reduce injury of passengers during traffic accidents. Associated with the development of security systems, there is the possibility of improving efficiency by the introduction of materials that lead to weight reduction, having a direct impact on fuel consumption and lower carbon emissions. The present work aims to study the behaviour of sandwich structures, composed by a foam core with two outer layers of metal sheet (all structure being aluminium). The study of the composite structure behaviour, its mechanical characterization and numerical modelling is essential to analyse the mechanical performance of structures based on this type of materials. This step is fundamental in preliminary design, since the different materials of the composite structure show different mechanical responses. The differences in mechanical behaviour are demonstrated by the axisymmetric compressive stress states tests and also by the influence of hydrostatic pressure in the yield of the aluminium foam porous material, while the yield of the homogeneous solid material (aluminium sheet) can be considered as pressure insensitive. In order to correctly characterize separately these two materials of the composite (outer layers and core), a set of tests were performed. The characterization of the aluminium sheet was performed in a series of tensile tests, using three different rolling directions. For the metal foam core characterization a series of uniaxial compression tests were performed. The experimentally obtained results were applied in the development of numerical models for this kind of sandwich structure. The models include elastoplastic constitutive relation, where a distinct plastic domain for different materials is accounted for, as well as, the influence of hydrostatic pressure in the yield of the porous material. Also, the validation of the elastoplastic models is performed by comparing results obtained by numerical simulations with those obtained experimentally.
New SPD Process of Incremental Angular Splitting
Authors: Rosochowski Andrzej , Rosochowska Malgorzata , Olejnik Lech
Published: February 2012

A new way of severely deforming ductile metals in order to refine their microstructure is proposed. It is called incremental angular splitting and originates from the idea of orthogonal cutting. It is intended to intensify plastic deformation in the cutting zone and lead to faster refinement of the microstructure. A laboratory experiment carried out on Al 1070 has proved the technical feasibility of the process. As the first indication of process capability, micro hardness measurements have been used to compare incremental angular splitting and incremental equal channel angular pressing.