bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-Dimensional Numerical Modelling of Hydrogen Diffusion in Metals Assisted by Both Stress and Strain
Authors: Toribio Jesús , Kharin Viktor , Vergara Diego , Lorenzo Miguel
Published: October 2010

The present work is based on previous research on the one-dimensional (1D) analysis of the hydrogen diffusion process, and proposes a numerical approach of the same phenomenon in two-dimensional (2D) situations, e.g. notches. The weighted residual method was used to solve numerically the differential equations set out when the geometry was discretized through the application of the finite element method. Three-node triangular elements were used in the discretization, due to its simplicity, and a numerical algorithm was numerically implemented to obtain the hydrogen concentration distribution in the material at different time increments. The model is a powerful tool to analyze hydrogen embrittlement phenomena in structural materials.
Approach to Iron Corrosion via the Numerical Simulation of a Galvanic Cell
Authors: Colicchio Giuseppina , Mansutti Daniela , Santarelli Maria Laura
Published: October 2010

A mathematical model of the galvanic iron corrosion is, here, presented. The iron(III)-hydroxide formation is considered together with the redox reaction. The PDE system, assembled on the basis of the fundamental holding electro-chemistry laws, is numerically solved by a locally refined FD method. For verification purpose we have assembled an experimental galvanic cell; in the present work, we report two tests cases, with acidic and neutral electrolitical solution, where the computed electric potential compares well with the measured experimental one
Prognostic Tools for Lifetime Prediction of Aircraft Coatings: Paint Degradation
Authors: Colwell John M. , Khan Javaid H. , Will Geoffrey , Fairfull-Smith Kathryn E. , Bottle Steven E. , George Graeme A. , Trueman Antony
Published: October 2010

A direct interrogation, portable analysis technique (portable FT-IR) and a novel environment-monitoring profluorescent sensor for studying aircraft coating degradation have been developed. For the direct interrogation approach, a standard military aircraft paint: 459-line Anzothane flexible polyurethane (lead free) has been used to illustrate a new potential field technique to evaluate coating service lifetime, portable FT-IR. This technique allows direct analysis of chemical changes within the degrading coatings and has the potential to evaluate service lifetime when coupled with advanced statistical analysis methods (chemometrics). The degradation environment monitoring sensors are embodied in a profluorescent environment-sensitive witness patch that may be analysed in-service by a field-deployable fluorescence spectrometer. Accelerated ageing for both the paint and the witness patches has been undertaken and their capabilities as aircraft paint degradation monitors assessed.
Characterization of Bronze Corrosion Products on Exposition to Sulphur Dioxide
Authors: De Filippo B. , Campanella L. , Brotzu A. , Natali S. , Ferro D.
Published: October 2010

In the main frame of the research aimed to model the corrosion growth on bronze surface, the objective of the work here reported has been to characterize the corrosion products formed on laboratory samples of bronze alloy (Cu Sn12), during the early stage of exposure to moist air with sulfur dioxide. A cycling corrosion cabinet was used to control 200 ppm gas concentration, relative humidity (RH) and temperature, according to the DIN 50018 (Kesternich test).The method is designed to evaluate how well the surface resists to sulfur dioxide corrosion; the test cycle consists of 8 hours exposure to sulfur dioxide at 40°C temperature and 100% relative humidity, followed by 12 hours drying at room condition.
Weight variation, Spectrophotometer, Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS), X-ray Diffraction (XRD) analysis were carried out for the tarnish products characterization. Some of the compound identified were brochantite (Cu4(OH)6SO4), chalcanthite (CuSO4•5H2O) cuprite (Cu2O), cassiterite (SnO2) and ottemannite (Sn2O3).
Electrochemical Methods to Assist Corrosion Control of Lightweight Alloys
Authors: Curioni M. , Thompson G.E.
Published: October 2010

In this work, the use of a differential aeration technique (split-cell) to assist understanding of contributions to the corrosion of an aerospace aluminium alloy is demonstrated. The setup comprised two similar specimens immersed in differentially aerated test solutions and coupled by a zero resistance ammeter. The individual electrochemical responses of the coupled specimens during linear polarization were interpreted in relation to the aeration condition, alloy composition and surface preparation. Further, the same setup was employed to investigate corrosion inhibition by observing the current and potential transients after inhibitor addition to the aerated or deareated compartment. It was found that the split-cell technique provides detailed understanding of the corrosion process in multiphase alloys and provides important information on inhibitor performance.
Surface Protection for Aircraft Maintenance by Means of Zinc Rich Primers
Authors: Bockmair Georg , Kranzeder Katharina
Published: October 2010

The aerospace industry urgently needs environmentally friendly materials and processes for corrosion protection of aluminium alloys in aircraft structures. Until now this has been achieved by hexavalent chromium based compounds in either surface pre-treatments or primers. Due to its carcinogenic properties the use of chromates is restricted and a ban is expected soon. Up to now an all over recognized replacement of chromates is not available for aircraft maintenance, although a lot of research has been done and promising results also exist for some chromium-free conversion coatings and for magnesium rich primers. WIWeB found out in laboratory scale and by flight trials that thin layers of zinc rich primers, if applied with dry film thickness of 10 – 20 µm, can be used successfully to prevent corrosion on aluminium for aircraft. Solvent based as well as water based zinc rich primers have been tested. The major part of the work presented is from further investigations which show, that another great improvement can be achieved, when thin layers of organic adhesion inhibitors like 2-aminopropyltriethoxysilane and 4-t-butylbenzoic acid are applied on the unclad Al 2024 panels, which had been scrubbed with abrasive pads before. This process is followed by the application of the thin film of zinc rich epoxy primer before the usual 2-pack epoxy primer is applied.
Thin, Nanoparticulate Coatings for the Improvement of the Corrosion and Passivation Behavior of AZ Magnesium Alloys
Authors: Feil Florian , Fürbeth Wolfram
Published: October 2010

We developed multilayered, purely inorganic coatings for the corrosion protection of AZ magnesium alloys. Polymeric acid-catalyzed sols form relatively dense coatings, but any direct contact to the reactive magnesium substrate has to be avoided. However polymeric sols based on SiO2, B2O3, Al2O3, ZrO2 and up to 5% of lanthanide salts can be used to seal samples with prime coat based on aqueous nanoparticle dispersions. Without organic network modification, these sealings have to be kept thin to avoid cracks. However if the coating process with aqueous dispersions and polymeric sols is alternated, a kind of lamellar sandwich structure can be formed which stays crack-free up to several layers. The performance and the protective properties of these coatings were studied with different methods (EIS, salt spray tests and electron microscopy).
Electrochemical Characteristics of PEO Treated Electric Arc Coatings on Lightweight Alloys
Authors: Nykyforchyn H.M. , Pokhmurskii V.I. , Klapkiv M.D. , Student Mykhajlo M. , Ippolito Juliet
Published: October 2010

The complex technology of the surface treatment of Al, Mg, Ti alloys for size reconstruction and strengthening is presented herein. This consists of electric arc spraying of aluminum alloys or powder wire in an aluminum shell and then treatment with plasma electrolytic oxidation (PEO). Once treated, oxide-ceramic coatings maintain extreme hardness, durability and resistance to wear. At the same time their corrosion-resistant properties are also significant. Dynamic potential dependences were studied for electric arc Al coatings and PEO treatments on Al, Mg, Ti alloys and corrosion currents were analyzed for exposure to a corrosive environment for a period of from 1 hour to 30 days. It was established that PEO treated coatings on Al alloys have a higher corrosion resistance than untreated sprayed coatings.
In Mg alloys, an intermediate layer of aluminum electric arc coating between the substrate and PEO-treated coating is necessary in order to ensure high corrosion resistance. This is due to the specifics of the formation of the MgO and Al2O3 oxide phases in the plasma discharge channels. At the same time Al coatings on Ti alloys, including those of post-PEO treatment, were characterized as having lower corrosion resistance within the range of electrode potential from corrosion potential up to repassivation potential, than were untreated Ti-alloys. Yet it was found that the corrosion resistance of PEO treated coatings increases at higher anode potentials. Under cathode polarization the hydrogen discharge is less likely to occur on PEO-coatings than on untreated Ti alloys which more effectively prevents hydrogenation.
Hybrid Coatings Based on Conducting Polymers and Polysiloxane Chains for Corrosion Protection of Al Alloys
Authors: Trueba Monica , Trasatti Stefano P. , Flamini Daniel O.
Published: October 2010

It was previously demonstrated that the use of a pyrrole-based silane (PySi) for surface treatment of Al alloys provides both active and barrier protection due to the deposition of a hybrid coating, containing polypyrrole and polysiloxane chains. To further explore these features, a wider range of Al substrates and different silane-based formulations in terms of silane molecule, solvent nature, water amount and pH, were investigated. Also, some tests were carried out by using aniline-based silane (AniSi). Structural/morphological characterization of the coatings, as well as the investigation of PySi solutions by diverse spectroscopic techniques, in addition to corrosion tests in NaCl, strongly support the very promising protection performance of the hybrid film. This is indicated as well from the preliminary results obtained with the AniSi-based approach. Thus, typical silane-based treatments with principally barrier action can gain in active properties if the silane compound contains monomers of conducting polymers as a funtional group.
Electrochemical Behavior of Nickel-Aluminum Alloys in Sodium Chloride Solutions
Authors: Rybalka Konstantin V. , Beketaeva Luiza A. , Shaldaev Vyacheslav S. , Bukhan’ko Nataliya G. , Davydov Alexey D.
Published: October 2010

The anodic and cathodic reactions involved in the corrosion process on several nickel-aluminum alloys including two intermetallic compounds NiAl and Ni3Al in the NaCl solutions are studied. A procedure of pretreatment of test specimens and measuring the anodic and cathodic voltammograms is developed. It enabled us to obtain reproducible results including Tafel portions of voltammograms. The corrosion potentials Ecorr and corrosion currents icorr are determined by the coordinates of the intersection of anodic and cathodic Tafel plots. The dependences of Ecorr and icorr on the alloy composition (the content of nickel in the binary nickel-aluminum alloys), on the concentration of NaCl, and рН of unbuffered NaCl solutions with the additions of HCl or NaOH are determined. The anodic behavior of the alloys in a wide potential range is studied using the potentiodynamic method and the method of stepwise raising anodic potential with an exposure of electrode at each potential for a certain time. The dependences of pitting potential on the concentration of solution are determined for two intermetallic compounds.
A Composite Coating for Corrosion and Wear Protection of AM60B Magnesium Alloy
Authors: da Forno Anna , Bestetti Massimiliano
Published: October 2010

In this paper a protection process against corrosion and wear for AM60B magnesium alloys, by multilayer approach, is related. The coating consists of a porous oxide layer, obtained in micro-arc anodizing regime, and two or three layers deposited by sol-gel technique. The anodic oxidation pre-treatment improves the adhesion of the sol-gel layers, which are responsible for the sealing of the anodic oxide pores and for the corrosion protection effect. In addition the multilayer system significantly improves AM60B alloy wear resistance. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were employed to assess morphology and crystallographic structure. Electrochemical polarization and wear tests were performed in order to evaluate the corrosion resistance behaviour and the wear resistance of the coated magnesium alloys.
Continuum Damage Model for Biodegradable Magnesium Alloy Stent
Authors: Gastaldi Dario , Sassi Valentina , Petrini Lorenza , Vedani Maurizio , Trasatti Stefano P. , Migliavacca Francesco
Published: October 2010

The main drawback of conventional stenting procedure is the high risk of restenosis. The idea of a stent that "disappears" after having fulfilled its mission is very intriguing and fascinating. The stent mass should diminishing in time to allow the gradual transmission of the mechanical load to the surrounding tissues. Magnesium and its alloys seem to be among the most appealing materials to design biodegradable stents. The objective of this work is to develop, in a finite element (FE) framework, a model of magnesium degradation able to predict the corrosion rate and thus providing a valuable tool to design biodegradable stents. Continuum damage approach is suitable for modelling different damage mechanisms, including several types of corrosion. Corrosion is modelled by a scalar damage field which accounts for the material strength loss due to geometrical discontinuities. As damage progresses, the material stiffness decreases. Corrosion damage results as the superposition of stress corrosion process and uniform corrosion. The former describes the stress-mediated localization of the corrosion attack through a stress-dependent evolution law similar to the one used in analytical models, while the latter affects the free surface of the material exposed to an aggressive environment. The effects of both phenomena described are modelled through a linear composition of the two specific damage evolution laws. The model, developed in a FE framework, manages the mesh dependency, typical of strain-softening behaviour, including the FE characteristic length in the damage evolution law definition. The developed model is able to reproduce the behaviour of different magnesium alloys subjected to static and slow-strain-rate corrosion tests. Moreover, 3D stenting procedures accounting for the interaction with the arterial vessel are simulated.
Prediction of Morphological Properties of Smart-Coatings for Cr Replacement, Based on Mathematical Modelling
Authors: Bozzini Benedetto , Sgura Ivonne , Lacitignola Deborah , Mele Claudio , Marchitto Mariapia , Ciliberto Antonio
Published: October 2010

In this paper we present an extension of a mathematical model for the morphological evolution of metal electrodeposits – recently developed by some of the authors – accounting for mass-transport of electroactive species from the bulk of the bath to the cathode surface. The implementation of mass-transport effects is specially necessary for the quantitative rationalisation of electrodeposition processes from ionic liquids, since these electrolytes exhibit a viscosity that is notably higher than that of cognate aqueous solutions and consequently mass-transport control is active at all practically relevant plating rates. In this work we show that, if mass-transport is coupled to cathodic adsorption of ionic liquid species and surface diffusion of adatoms, it can lead to electrodeposit smoothing. This seemingly paradoxical theoretical result has been validated by a series of Mn electrodeposition experiments from aqueous baths and eutectic ionic liquids. The latter solutions have been shown to be able to form remarkably smoother coatings than the former ones. Mn electroplates have been proposed for Cd replacement and their corrosion protection performance seems comparable, but so far the required surface finish quality has not been achieved with aqueous electrolytes. Ionic liquids thus seem to provide a viable approach to aeronautic-grade Mn electroplating.
Fabrication, Characterisation and Application of Carbon Nanotube Polymer Composites
Authors: Zhang Liang Chi
Published: October 2010

Carbon nanotubes (CNTs) have been used in making composites because CNTs have high strength, large aspect-ratio and excellent thermal and electrical conductivity. However, to realize the wide applications of CNT composites, further R&D must be carried out. This review will discuss some fabrication, characterisation and application issues of CNT polymer composites. Aspects to outline are purification, dispersion, alignment, stress transfer, interface bonding, wear and friction and rheological properties. Some research challenges will be briefly highlighted as well, including the mass production of long and aligned CNTs at low cost, and the optimization of the microstructures, properties and functioning features of CNT composites.
Dynamic Multibody Simulation of a 6-DOF Robotic Arm
Authors: Li Bin , Yao Xi Fan , Wang Chun Bao , Lou Hui Dong
Published: October 2010

Based on the kinematic model with Cartesian structure, Newton-Euler like algo¬rithm being employed to solve the nonlinear equations of motion and constraints in real-time application, and dynamic multibody simulation, a novel integrated design for a 6-DOF ro¬bot is investigated, and the interfaces required for the implementation of different computer aided engineering (CAE) tools used in the design is addressed [1].The presented method in this paper was analyzed and verified by the numerical and physical 6-DOF robot model, the result shows that the topologic projection me-thod [2] is stable. The design experience accumulated will be very useful for the future product de-sign.
Reliability Study for Creep Life of Single Crystal Turbine Blade under Random Crystal Orientations and Random Loads
Authors: Gao Zong Zhan , Yue Zhu Feng
Published: October 2010

For the single crystal (SC) Ni-based superalloys, it is difficult to avoid orientation variation along airfoil stacking line of the SC turbine blade. At the mean time, the loading of turbine blade is uncertainly during the working. In this work, the creep life of the SC turbine blade is determined by the finite element analysis (FEA) based on the crystal slip theory. The orientation variations are measured based larger numbers commercial turbine blade made of SC superalloys. Furthermore, Monte-Carlo method and the forth moment method are presented to analysis the reliability for creep life of SC turbine blade under random crystal orientations and random loads based on the FEA method. The basic variables sensitivity are comprehensively analyzed by the forth moment method.
Development of Hydraulic Control Jam Release Device for Workover
Authors: Jia Guang Zheng , Wang Shuo , Zhang Fu Chen
Published: October 2010

Developed a device used to assist workover rig in lifting stuck tubing strings from the well during workover treatment, it can create well economic benefit for oil field. The device adopts remote hydraulic control, which is safe and reliable. The structure and work principle of the device is illustrated. The jam release device is mainly made up of hydraulic cylinders, hydraulic pump and hydraulic control valves. With the coordination between lifting hydraulic cylinders and hydraulic slips, the device can lift tubing strings from the well. The important loading unit of the device is analyzed by finite element. The working pressure is made from 5MPa to 20MPa, corresponding to lifting force range of 229kN to 915.6kN, which can meet the jam release force in workover treatment.
Computer Simulation for the Orthogonal Milling Process of Asphalt Concrete
Authors: Zhou Li Qun , Li Yu Ping , Liu Hong , Xing Guo
Published: October 2010

So as to design the pavement planer, it is necessary to study the milling performance of asphalt concrete. In this work, a coupled thermo-mechanical plane-strain large deformation orthogonal cutting finite element model is presented to simulate the asphalt concrete milling process and predict the stress and temperature field on the cutter. Chip separation is considered by applying shear fracture failure criteria and element deletion and adaptive mesh technique. Two contact pairs are defined. Contact pair 1 defines the milling path, and contact pair 2 defines to prevent the formed chip enter into the workpiece. The Johnson-Cook’s constitutive relation is adopted for the asphalt material. The cutter surface friction and heat conduction are considered. The computation indicates that the maximal cutting force will change from 3.967KN to 10.494KN if the cutting speed is between 1000mm/s and 2000mm/s for the pavement planer of BG2000.
A Study on Design of a Breech Mechanism Test-Platform Drive
Authors: Yao Jia Jun , Ma Ji Sheng
Published: October 2010

The breech mechanism is a very important part of artillery with a high failure rate. It is planned to build a test-platform for the investigation of the breech mechanism. By this test-platform the motion of the breech, while the artillery is shooting, can be simulated as the same. While the artillery is shooting, the energy for the opening and shutting action of the breechblock comes from the impact between the breechblock operating cam and crank, when the breech is returning. But this action of a hugely heavy thing is very difficult to simulate. So the negative direction action is considered, which makes the breechblock operating cam moved to impact the crank. In this paper the virtual prototype model based on ADAMS is used to measure the load etc. of the key-parts of the breech mechanism by simulation experimentations.
Effect of Sn on Glass Formation Ability and Crystallization Behaviors of Cu-Based Bulk Metallic Glass Alloy
Authors: Zhang Deng Wei , Teng Xin Ying , Li Bo , Zhang Wen Jie
Published: October 2010

Cu-based bulk metallic glasses (BMGs) with 5 mm in diameter were synthesized by copper mold casting. The effects of tin (Sn) addition on glass-forming ability (GFA), thermal stability of BMGs were investigated. It was found the addition of 4 at. % Sn is effective for an increase in GFA. The crystallization behaviors of Cu-based bulk metallic glasses during continuous heating are investigated mainly by differential scanning calorimeter(DSC).The results show that the characteristic temperatures(Tg,Tx and Tp) shifted to high temperature region with increasing of heating rates. The activation energies Eg, Ex and Ep, corresponding to characteristic temperatures Tg, Tx, and Tp, respectively, were obtained from Kissinger and Ozawa equations. The calculated activation energies agree well with Kissinger or Ozawa equations due to the almost invariability of the crystallization volume fraction at the characteristic temperatures for different heating rates.
The Ontology Mapping Technology Based on the Information Coding Ontology Model
Authors: Jiang Jian Jun , Wang Jun Biao , Liu Nan
Published: October 2010

To our knowledge, there is no paper in the open literature dealing with the topic in the title. This paper provides an Information Coding Ontology Model (ICOM) to shield semantic heterogeneous of information resources, and to achieve information integration. Sections 1 and 2 of the full paper present the information coding ontology model and its formal definition, then design the mapping framework of the information coding ontology model. Section 3 discusses the mapping algorithm of the information coding ontology model from three aspects: semantic similarity analysis, obtaining semantic similarity algorithm, and semantic mapping and its implementation. Section 4 gives Fig. 7 as the mapping flow chart of the information coding ontology model and uses a numerical example to illustrate the four-step procedure of the mapping implementation process.
The Flow Analysis of Automotive Power Steering Gear Assembly Based on Fluent
Authors: Cheng Kai , Li Tang Zheng , Li Guang Ming
Published: October 2010

In allusion to the problem that the newly developed pumping units using for automotive power steering gear assembly can not clean the inside oil, the paper takes the key flow channel as the research object, establishes the 3D geometrical model, meshes it, and then uses the Fluent software to simulate and analysis the flow. After setting different working conditions as diverse pressures of the import and export, the paper gets some visual results of the flow velocity vector and the flow pressure vector. At last, according to the characteristic diagrams of the flow received from the stimulation, the paper gives some theoretically explanation to the phenomenon of remaining a small quantity of oil and provides an important basis to set some important parameters of the pumping machine. Meanwhile, it gives some reference significance for the optimization design of steering gear.
Analytical Comparison of Structures of Heavy Gas Turbine Rotor’s Support
Authors: Sun Wen Lei , Zhang Yan Biao , Guo Jian
Published: October 2010

This paper aims at the structures of heavy gas turbine rotor’s support, the analyze method of fluid-solid couple and that of thermal-solid couple is adopted to simulate by ANSYS CFX, by compared with the deformation of the different structures of their support, it sums up that the tangential support is the best structure. Furthermore, the deformation of the tangential support under different conditions is analyzed, such as the different temperature of gas and the ultimate load of shaft, that supports the research of the working mechanism of the sliding bearing and the dynamic characterization, and finally the research achievements are expanded to apply the study of the stability of shaft power, providing a basis for the study and development of the future’s gas turbine technology.
3-D Numerical Simulation and Experiment Study on the Wear of Piston Ring-Cylinder Liner
Authors: Zhang Jian Ping , Jiang Yan Kun , Liu Xin , Dong Zhe Lin
Published: October 2010

Aiming at a large marine diesel engine, a mathematical model for the 3-D elastohydrodynamic lubrication analysis of piston ring-cylinder liner was presented. The average Reynolds equation and asperity contact approach were combined with the elastic deformation equation. The asymmetry in the circumferential direction, gas blowby and the effect of temperature and pressure on the oil density and viscosity were considered. The 3-D wear simulation of piston ring-cylinder liner was performed when the diesel engine was operated under warm start and cold start conditions, respectively. The 3-D distribution rules show that the first gas ring has the biggest wear loss, and the maximum wear loss of cylinder liner occurs in the vicinity of TDCF. Finally, the results matched well with the wear measurements, and it indicates the present method is effective and can help engineers to improve the tribological performance of the diesel engine.
Study of Pressure Pulsations Attenuation in Hydraulic System
Authors: He Zhi Yong , He Qing Hua
Published: October 2010

A pressure pulsations reactive attenuator for controlling hydraulic system was investigated through theoretical and experimental means. The attenuator consists of many “mass-spring-damp” lumped parameter vibration systems with different natural frequency. Through the fluid-structure coupled vibration, the fluid vibrations are converted into structure vibrations. And on this device, the filter attenuation model was established and the simulation results show that, changing the system flow pulse frequency (from 186 Hz to 225 Hz) near to the resonance frequency (236 Hz) of a certain lumped parameter vibration system, the attenuator has a good effect because of component resonance attenuating hydraulic pulsation energy. To verify the correctness of simulation results, the experiment is tested and the results are homology. It provides a new practical technique for hydraulic system vibration control.
A New Method for Process Plan Reasoning in Injection Mould Repairs
Authors: Wang Yi
Published: October 2010

Mould-repair is an important task in the mould production and depends especially upon the experience of the engineer. It is much full of subjectivity and uncertainty. How to find the knowledge of mould repair and establish the mould repair solving project is an important problem for all the injection mould manufacturers in the industry. Using the Bayesian networks reasoning to help the technician establish the mould-repair solving project was put forward. The mould-repair Bayesian networks (MRBN) reasoning model was established according to the characteristic of mould-repair solving project. The reason control tactic of the process plan system and the reasoning engine of MRBN were designed. The application example about the shrinkage, ill-full injection, gas-obstructed is presented to prove the correctness of the method. The conclusion shows that it can help the engineers analyze the cause of problem well and recommend some more useful solutions.
Numerical Simulation of the Flow Field in Cavitations Nozzle for Impinging Streams Reactor
Authors: Li Qin , Wang Hui Lin , Li Fu Bao
Published: October 2010

The pressure distributions in cavitations nozzle of three different structures were studied by Hydromechanics theory, the models and mashes were completed by using Gambit software, for the conditions of the inlet pressure to 20MPa and the outlet pressure to 0.1MPa, the flow field within cavitations nozzles is simulated based on the standard k-ε model and the SIMPLE algorithm with Fluent. The result of numerical simulation is consistent with that of analytical calculation. Simulation results show that the flow has a strong shear effect with the surrounding medium in the diffuser, resulting in significant negative pressure, which is conducive to the formation of cavitations bubbles. The angle nozzle is best selected for impinging streams cavitations reactor on this basis in the paper.
The Simulation about Collision of the Truck Fence
Authors: Zhang Yu Bao , Zhang En Hui
Published: October 2010

The collision characteristics of the truck fences are very important to occupant safety in car, when the car’s front collisions the tail of truck. This study is a kind of the truck fence structure and simulates its crash. First, simulates the original truck guards. Second, improves the truck fence, and the truck fence is simulated by ANSYS / LS-DYNA. Finally, the simulation results and unimproved simulation results are compared. The results show that the dynamic response characteristics (deformation, velocity and acceleration) and the absorb energy (interna energy and kinetic energy) of the improved model are significantly enhanced.
Modeling and Kinematics Characteristic Analysis of Twist Beam Rear Suspension Using ADAMS/Car
Authors: Tang Ai Hua , Jian Ou , Deng Guo Hong
Published: October 2010

The multi-body system analysis has become one of the main simulation techniques to calculate the kinematics characteristics of a car suspension under wheel travel or to build a virtual prototype model of a vehicle in order to predict the vehicle dynamics performance. The modeling of twist beam rear suspensions is always difficult for the unique structural behavior of this component. A non-linear method based on multi-body dynamics software (ADAMS/Car) was used to represent the twist beam within the suspension system. The kinematics characteristic analysis of the rear suspension was realized by means of ADAMS/Car. The main suspension parameters (toe angle, camber angle and wheel track variation) were calculated by changing wheel travel. The result shows that the method of suspension kinematics analysis by using ADAMS/Car can be used in the design of suspensions conveniently.
Reliability Simulation and Prediction of Mechanical Equipment for Maintenance
Authors: Huang Liang Pei , Gong Zheng Li , Yue Wen Hui
Published: October 2010

The mechanical equipment faults result from parts failure in the period of service time, due to reassembly and maintenance, the reliability model for mechanical equipment is broken, so it is necessary to research and estimate the safety reliability of mechanical system. Based on the time-to-failure density function of parts, the mechanical system reliability model is constructed to track the change course of age structure of part population for the mechanical systems that are reassembled and maintained. By means of simulation of the system reliability model, concerned parameters with mechanical systems service life are defined, it is discussed how the time-to-failure density function have influence on the service life for mechanical systems undergoing reassembly and maintenance. It is significant to estimate reliability and failure rate of systems and to establish reasonable maintenance policies.
Design of Y422 Retrievable Fracture Bridge Plug and Analysis of Slip Characteristics
Authors: Li Dian Xin , Zhao Hong Lin , Liu Xian Long , Zheng Shan Jun , Geng Dai , Zhang Shi Min
Published: October 2010

According to the demand of exploiting the poor-thin oil layer in Daqing oilfield, Y422 retrievable fracture bridge plug is designed. Match usage of this bridge plug and other instruments can fracture multiple oil reservoirs with one-trip string, which is characterized by simple technology and safety operation. This bridge plug has realistic significance and practical value for improving oilfield economic benefits and provides an extensive application prospect. After setting process, the slips brace the bridge plug whose performance have a directly influence on the oil well productivity and production safety. In order to make sure that the bridge plug slips can meet the anchoring requirement, the actual working state of the slips system was analyzed by using finite element software, and the stress distribution rules were obtained. The results provide theoretical basis for optimizing slip structure and improving working reliability.
Optimization Design of the Composite Hub Connection Structure Based on ANSYS Software Technology
Authors: Sun Hua
Published: October 2010

This article through analysing coupler's structure, involute spline's stress situation, the tooth face contact intensity, the tooth root bending strength, the tooth root shearing strength, tooth face wear ability and the external spline reverse and curving bearing capacity carry on the precise computation and the examination, simultaneously a multianalysis bulge tight joint set of structure and the correlation computation examination, has established the shaft bossing compound coupler main spare part structure type. In this article based on the shaft bossing composite construction optimization design is targeted mainly flexibility swelling ring shape to optimize the design, change that flexibility swelling ring cone-cone angle, which makes flexible swelling ring Auxiliary T-twisting greater. In the analysis, it is necessary to use the software ANSYS, through the creation of the shaft bossing composite construction of the parametrization model, a flexible swelling ring cone-cone angle of the design variables and flexibility swelling ring allowable material stress as binding conditions, bulging with flexible support ring-twisting as the objective function of T,right propeller shaft coupler hub composite structure axisymmetric analysis, contact analysis and design optimization, inflation reached a flexible support ring largest T-twisting, work stress does not exceed the allowable material stress, elastic swelling ring-cone angle of the optimal solution.
A Boundary Element-Free Method for Fracture Analysis of 2D Anisotropic Solids
Authors: Sun Yu Zhou , Li Dong Xia , Wang Hui
Published: October 2010

This paper presents a boundary element-free computational method for the fracture analysis of 2-D anisotropic bodies. The study starts from a derived traction boundary integral equation (BIE) in which the boundary conditions of both upper and lower crack surfaces are incorporated into and only the Cauchy singular kernal is involved. The boundary element-free method is achieved by combining this new BIE and the moving least-squares (MLS) approximation. The new BIE introduces two new variables: the displace density and The dislocation density. For each crack, the dislocation density is first expressed as the product of the characteristic term and unknown weight function, and the unknown weight function is approximated with the MLS approximation. The stress intensity factors (SIFs) can be calculated from the the weight function. The examples of the straight and circular-arc cracks are computed, and the convergence and efficiency are discussed.
A Framework Based on Support Vector Regression for Robust Optimization
Authors: Yao Bi Qiang
Published: October 2010

The availability of efficient and accurate metamodel for optimization computation is crucial to the success of applications of robust optimization of computationally intensive simulation models. To address this need, a framework has been presented for robust optimization on problems that involve high dimensional. The framework was combined with support vector regression (SVR) approximation model and a genetic algorithm (GA). The performances of SVR were compared with those of polynomial regression (PR), Kriging and back-propagation neural networks (BPNN). The results showed that the prediction accuracy of SVR model was higher than those of others metamodels. The applicability of the algorithm developed by combining SVR and GA was demonstrated by using a two-bar structure system study, and was found to be accurate and efficient for robust optimization. The optimization framework was effectively utilized to achieve a potential performance improvement.
Finite Element Method Analysis and Optimal Design of Roller Convexity of Tapered Roller Bearing
Authors: Wang Zhi Wei , Meng Ling Qin , Hao Wen Si , Zhang E
Published: October 2010

The different designs of rollers with varied convexity give different stress distribution and elastic deformation. It is directly related to the load capability and the life length of the roller bearing. With the Finite Element Method(FEM), by analyzing the stress distribution of roller busbar and raceway contact area in the design of different rollers with varied convexity of tapered roller bearing, the paper gets the best solution for the design of convexity of tapered rollers and the cause of roller bearings’ early destroy. The optimal result shows that the service life of this bearing has been improved by 93%. Hence, a more efficient method of improving the service life of rollers is got.
Revision of Tooth Surface in Order to Compensate the Load Deviation of the Plastic Gears
Authors: Liu Hu Ran
Published: October 2010

Based on the torsion deformation the gear body and the contact deformation of tooth surface, the fundamental equations of load of the gear was presented, thus established the theoretical basis of the load derivation of the gearing. In this paper, the torsion deformation of the circular arc gears is analyzed first. Then the second order differential equation for the tooth surface load distribution of the involutes gears has been deduced. The equation for the load derivation of the spur gears is presented while the errors of original tooth surface are under consideration. Revision of tooth surface in order to compensate the load deviation of the plastic gears is presented in this paper.
FEM Simulation on Cold Rolling of Outer Spherical Bearing Ring
Authors: Zhao Xiu Ting
Published: October 2010

Ring rolling theory based on completion of the mold, rough and technical parameters of the design, application Abaqus software to build three-dimensional model of rolling, and the use of Abaqus / Explicit algorithm of external spherical bearing outer ring of cold ring rolling simulation and analysis come to different mold shape, size, structure and guide roller feed specifications on the forming process, reveals a spherical bearing outer ring of the mechanism of cold ring rolling, gets die structure is different, different size core roller, guide rollers with different combinations of cold rolling play a crucial role in forming quality. At the same time by rolling the solution results demonstrate the power of cold ring rolling of the nonlinear characteristics. Revealed the ring rolling process is a complex interaction of multi-parameter deformation coupling.
Study of the Geometrical Error Modeling of NC Lathe Based on Multi-Body System Theory
Authors: Wang Xiu Shan , Li Yan , Yu Yong Chang
Published: October 2010

The geometrical error modeling of the numerically controlled (NC) lathe is the key technique to kinematics design, precision analysis and error compensation. The study gives out the modeling process of the generally geometrical error model based on the multi-body system theory for the multi-axis NC machine tools. By the multi-system theory, using the low series body arrays to describe the complex mechanical system, the article has finished the geometrical error modeling of the numerically controlled lathe, analyzed the influence on the model of error of perpendicularity between the linear axes. The modeling method is highly-efficient and can not be affected by the structure of the NC machine tools. The error compensation and command correction can be implemented by the geometric errors model.
The Dynamic Simulation Analysis of the Vehicle Safety Belt Retractor
Authors: Zhao Xiao Yu , Xing Yan Feng , Zhao Bo
Published: October 2010

This paper searched a way in order to solve relations between the structures and locking performances for vehicle safety-belt retractor, introduced the emergency locking retractor operating principles, including roll-up mechanism, bearing-strength mechanism, sensitive locking organization. Established the movement equations include the car-body which accelerates, the car-body lean and the pull out strap which accelerates, according to the equations of motion may the design performance parameters and structure parameters. Based on above research, applying MSC.ADAMS to dynamic simulation analysis, to make a analysis between the turn angle of strap-shaft and time, provided a check mean for improving performance of retractor, so as to accord the compulsorily standard ECE. R16: uniform provisions concerning the approval of safety-straps, restraint systems, child restraint systems and ISO fix child restraint systems for occupants of power-driven vehicles and GB14166-2003: safety strap and locking system used for adult passengers of vehicle.
Mechanics Model and Finite Element Simulation of High Speed Orthogonal Cutting of Titanium Alloy
Authors: Yang Yong , Wang Yu Ling , Li Chang He
Published: October 2010

Though a lot of research works have been done, some key technologies of finite element simulation have not been resolved completely. A detailed finite element model of high speed orthogonal cutting of titanium alloy Ti6Al4V is developed. Several mechanics models of cutting process, such as material constitutive model, chip separation model and chip damage model, are implemented to improve finite element simulation accuracy. The chip shape and cutting force agree well with experimental results, which show the finite element model developed in this study is reasonable. Using this finite element model, chip formation process of titanium alloy Ti6Al4V is simulated. Results indicate that the material between the shear bands is only weakly deformed, and the deformation is stronger on the tool side of the chip. This work will be a base for process parameter optimization, tool’s optimization selection and design during high speed cutting of difficult-to-cut titanium alloy.
The Study on Framework and Functions of Integrated Design Environments for Preliminary Design
Authors: Xu Cheng Dong , Hu Chun Sheng , Cao Xiao Bo
Published: October 2010

For complex product design, many software and tools are used, and large scale intermediate data with heterogeneous formats and complex relationships are produced in preliminary design. Efficient organization and management of data are very difficult. The integrated design environments(IDE) are useful to solve this problem. This paper gives an overview on IDE and some correlative key technologies. According to characteristics of preliminary design stage, a framework of IDE is put forward in this paper and the system function components are analyzed. The framework includes some innovative methodologies, such as task-drove design by workflow management, design tools and software seamless integration, and design knowledge templates. The realization of IDE is presented to illustrate the applicability of the new framework.
Integration of 3D-Routing for the Design of Molded Interconnect Devices
Authors: Zhuo Yong
Published: October 2010

One of the fundamental innovations in the field of mechatronics is the direct material integration of mechanical and electronic functions using Molded Interconnect Devices (MID technology). Unlike conventional circuit boards, they are not limited to two dimensions but offer the possibility to arbitrarily lay printed circuit traces on the surfaces of the 3D carrier, traditional 2D routing function in EDA cannot be directly applied in MID design. In this paper, two new 3D automatic routing methods are introduced. One method is based on a grid graph and extends Hadlock’s minimum detour algorithm; the other is gridless and combines the A*-algorithm and an extension of Hightower’s algorithm. The related 3D routing functions, which are not supported by conventional MCAD und ECAD systems, are integrated in the design system MIDCAD. With these 3D routing functions, MIDCAD enables a more effective product design based on the MID technology.
CAD/CAE Technology and its Application on Nonferrous Alloy Casting
Authors: Liao Dun Ming , Chen Li Liang , Zhou Jian Xin , Liu Rui Xiang
Published: October 2010

The nonferrous alloy castings will be much demanded with the development of aerospace, light-weight weapons and automotive industry. Casting CAD/CAE technology has played an increasingly important role in foundry. It can help technician to design casting process and simulate heat transferring and molten metal flowing before actual production. Firstly, the main contents and basic principles, mathematical models of casting CAD and CAE were introduced. Secondly, the casting CAD/CAE technology route was interpreted, and then several CAD/CAE applications of casting process design and simulating were carried out on nonferrous alloys, such as aluminum, magnesium and copper. The results indicate that CAD/CAE technology can be applied to casting process design and predict casting defects which usually occur during the casting mold filling and solidification process, it can provide references to optimize casting process, so as to improve casting quality, reduce the rejection rate and shorten the development cycle of new products.