bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Fatigue Behaviors of Nodular Cast Iron QT800 by Laser Shock Processing
Authors: Wang Zhi Ping
Published: October 2010

The surface of nodular cast iron QT800 was processed with LSP, its micro-structures, residual stress and fatigue test were compared before and after LSP, and the rupture morphologies of fatigue test were analyzed, the effects of LSP on fatigue behavior of QT800 were discussed. The results shown that the compressive residual stress of QT800 by LSP is over 400MPa, and its fatigue life is increased 20% than that in primitive state; the fatigue resource or the sample by LSP is produced near the graphite, compressive residual stress and refined grain effectively delays cracks initiation of the fatigue source, the expansion speed of fatigue cracks is decreased, which increases fatigue life of QT800.
Numerical Simulation of Thermal Deformation of High Speed and Exactitude Thermo Grip
Authors: Wang Z.G. , Xu L. , Wei Huali Gang , Xu L.D. , Yu H.H.
Published: October 2010

Built the thermal deformation model of high-speed and exactitude thermo grip according to the thermal deformation theory .And numerical simulation of the thermal stress was performed by finite element analysis software of ANSYS. The thermal deformation experiment had be done with φ10 and φ16 specifications thermo grip. Experimental data and simulation analysis are fit well. It provides the theory support for the optimal design of thermo grip.
FTA-BN Approach to Risk Assessment of Die Casting Die and Risk Mitigation Solution in 4Ps Development Framework
Authors: Jiang J.J. , Zhou Yong Quan , Miao Miao
Published: October 2010

In this paper the proposed methodology of FTA-BN (Fault Tree Analysis - Bayesian Networks) approach to risk assessment is outlined and its application is demonstrated using a simple case study of on-time delivery risk. First the potential risk scenarios are identified and represented in term of a fault tree, next, using the fault tree and prior probability, posterior probabilities are estimated and inferred by Bayesian approach. A creation of a best-of-breed work flow, which is based on the standardization of 4Ps framework of development and management processes of die casting die has been established for the solution to mitigate the risk analyzed by Bayesian approach. 4Ps framework covers from the prioritized customer outcomes and die casting die buy-in stage to EV/DV/PV building trial run and die casting mold termination stage with the scalability and flexibility, not only to improve die casting die quality and on-time delivery, but also to mitigate any risk in design and manufacturing process.
Study on Atmospheric Corrosion Behaviour of Sicp/Al Composite
Authors: Zhou Xian Liang , Li Duo Sheng , Zou Ai Hua , Hua Xiao Zhen , Ye G.Z. , Chen Qing Jun , Zhang Jian Yun , Tang Yong Jin
Published: October 2010

SiCp/Al composite was fabricated by the method of pressureless-infiltration. In atmospheric environment, the atmospheric corrosion behavior of SiCp/Al composites (ZL101+49%SiC+5%Mg) was studied by mass loss, optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR), respectivelhy.The results show that the corrosion rate of the SiCp/Al composites increases with increasing of time in atmospheric environment. Pitting corrosion is the main characteristic of SiCp/Al composite, and corrosion area gradually extends around with time increasing. At last, sheet like corrosion substrates distribute in the surface of n the SiCp/Al composites. Amorphous Al2O3 and amorphous AlxSO4yOHz are the main corrosion products.
Experiment Research on Grinding of Optical Glass with Indigenously Developed Monolayer Brazed Diamond Grinding Wheel
Authors: Zhang Bei , Xu Hong Jun , Fu Yu Can , Su Hong Hua
Published: October 2010

Conventional grinding of optical glass will normally result in not only much lower material removal rate but also short service life of grinding tools, which causes the high fabrication cost of optical glass. This paper focuses on the precision grinding of optical glass with the indigenously developed monolayer brazed diamond grinding wheel. Before grinding process a precision dressing is conduct. The dressed grinding wheel topography is observed. Through precision dressing the grinding process achieves moderate surface finish as well as ensures certain grinding efficiency. The ground surface of the optical glass workpiece is made up of micro-pits and glazing zones and the obtained surface roughness variation with the process parameters is analyzed. The experiment shows that the developed diamond grinding wheel is suitable to the application of optical glass machining.
Effect of Adding Er on Interfacial Reactions between Sn-3.0Ag-0.5Cu Solder and Cu Substrate
Authors: Li Hui , Lu Bin
Published: October 2010

The formation and the growth of Cu-Sn intermetallic compound (IMC) layer at the interface between Sn-3.0Ag-0.5Cu-xEr(x=0, 0.1) solder and Cu substrate during soldering and aging were studied. The results show that Cu6Sn5 IMC is observed at the interface between solder and Cu substrate in all conditions. After aging for 120 h, the Cu3Sn IMC is then obtained. With increasing aging time, the scalloped Cu6Sn5 structure changes to a plate structure. The Cu3Sn film always forms with a relatively planar interface. By adding a small amount of the rare earth element Er (only 0.1%, mass fraction) into the Sn-3.0Ag-0.5Cu solder alloy, the growth rate of the Cu-Sn IMC at the interface of solder alloy system is decreased. When the time exponent is approximately 0.5, the growth of the IMC layer is mainly controlled by a diffusion over the studied time range.
Open CNC System Based on Embedded Monitoring Unit
Authors: Wang Tai Yong , Qiao Zhi Feng , Liu Qing Jian , Hu Miao
Published: October 2010

Regarding to the requirement of machine tool state monitoring in the functional diversity of CNC system, the prototype of an open CNC system based on embedded monitoring unit is studied and constructed. According to the analyzing of the development status of machine tool state monitoring, an embedded monitoring unit model, which connects with the CNC system through the field bus and can be reconfigured when the monitoring target changed, is set up with the ARM + DSP master-slave architecture, through which the state of machine tools can be accessed by the CNC system. In view of the development trend of open CNC system, a four-layer open architecture reference model is proposed, which will meet the demand for structure adjustment and function expansion. In addition, the key supporting technologies in the system design are also researched, so as to provide a feasible solution for the maintenance and multifunction integration of CNC equipment.
Study on Adsorption Characteristics of Ni (II) by Palygorskite
Authors: Lin Shao Hua , Li Jie Rui , Wang Zheng , Jing Zhao Qian
Published: October 2010

Adsorption characteristics of Ni (II) by Palygorskite were investigated using a batch adsorption, and the effects of various experimental parameters were discussed. Results showed that the adsorption capacity of palygorskite for Ni (II) increased with increasing contact time and amount of adsorbent. Ni (II) adsorption onto palygorskite was well fitted by the pseudo-first-order kinetic model. Adsorption capacity increased to a maximum as the treating temperature increased to 673K. Heat-activation at 773K resulted in degradation of channel structure and adsorption capacity loss of palygorskite. With increasing HCl concentration of acid treating solution, adsorption capacities for Ni (II) decreased firstly and then increased, a minimum was obtained at 4mol/L of HCl concentration.
Experimental Study on Thermostatic Cutting Nickel-Base Superalloy GH4169
Authors: Hao Zhao Peng , Han R.D. , Gao D.
Published: October 2010

Nickel-base super alloy GH4169 is difficult to cutting and tool wear is very serious, because of its high strength, poor thermal conductivity, and serious work-hardening. In order to choose reasonable cutting parameters as to improve the processing efficiency, the cutting experiments were crarried out and the changes of workpiece material physical in cutting process were studied, and then thermostatic cutting method based on the longest distance is proposed in this paper. The best cutting temperature of carbide cutting tool YG8-GH4169 has been given. The experiments using diferent cutting parameters has proved the feasibility of thermostatic cutting method. Finally, the empirical formula of thermostatic cutting based on the cutting speed and feed rate is proposed, when using YG8 cutting GH4169.
Research on RFID and Vision-Based AGV Navigation
Authors: Man Z.G. , Ye Wen Hua , Zhao P. , Lou Pei Huang , Wu T.J.
Published: October 2010

In order to implement vision-based navigation of AGV (Automated guided vehicle) with complex path, a method incorporating RFID (radio frequency identification) technology with image processing technology is proposed, in which RFID technology is used to recognize nodes and image processing technology is used to detect path. Straight line path is detected by Hough transform in case that AGV runs straightly, while curve path is detected by line scanning in case that AGV turns right and left. Experiment results show that, with the method presented in this paper, the navigation of path tracking for AGV is implemented well.
Study on Data Acquisition System for Cold Extrusion of Internal Threads Based on Virtual Instrument
Authors: Zhang M. , Li Xiang Feng , Zuo Dun Wen , Miao Hong
Published: October 2010

According to the airplane landing gear anti-fatigue manufacturing, a new data acquisition system for cold extrusion of internal threads was developed based on LabVIEW platform. And the acquisition, presentation and storage of the data including the torque moment, temperature and tap vibration for cold extrusion process of internal threads were realized. The problem that the data lost during the acquisition was resolved by using the producer/consumer design mode. The experiment that cold extrusion of internal threads in Q460 high strength steel which size is M22×1.5 was completed, and the result shows that the system is reliable and meets the requirements of the measurement.
The Influence of Surface Tension on Lubrication Film Thickness and Pressure
Authors: Liu Jian Ping , Zhang Xin Yi , Jia Qing Xuan
Published: October 2010

Modified Reynolds equation is deduced considering surface tension in this paper. The influence of surface tension on lubrication and elastohydrodynamic lubrication is analyzed. Result shows surface tension has apparent influence on oil film thickness. It makes minimum film thickness increase under relative thin film thickness. The influence decreases rapidly with the increasing of film thickness. Surface tension has little influence on oil film pressure distribution.
New Technology of Solospun and Prospect of its Application and Development
Authors: Zhao Bo
Published: October 2010

In the paper the new technology of solospun and its principle of spinning are introduced. The yarn produced in this method is better than the normal yarn with the same count. This kind of yarn has the high strength and the characteristics of high resistant to abrasion and less hairiness etc. It can improve the efficiency of single strand to weave as well as provide the advantageous conditions for developing high count, light and thin product. Technology of solospun has wide prospect for development and application.
Study of Traction Properties of Three Space Lubricants Used for Rolling Bearing
Authors: Liu Jian Ping , Zhang Xin Yi , Jia Qing Xuan
Published: October 2010

Based on Johnson and Tevaarwerk’s model, traction coefficient was obtained for operating conditions representative of spacecraft applications. In this model input data come directly from rheological experiments or are derived from other measurements through physical relationships. Theoretical results were also compared with experimental ones which were measured for the same operating conditions.
Ocular Aberrations Measurement Combined with Subjective Visual Compensation
Authors: Xu A.C. , Chen J.B. , Zhang P.M. , Wu J.J.
Published: October 2010

Objective: The human eye is an imperfect refractive system which not only has defocus and astigmatism, but also spherical aberration, coma and anomalistic high-order aberrations, all of which have influence on the imaging quality of retina. Further research revealed that human eye visual imaging is not only connected with refractive system, but also is closely related to the subjective judgment of human brain and the process of neural system. Method: Wave-front aberration measurement method and its measuring system which have subjective visual compensation are proposed and conducted in combination with objective measurement, which ensure more accurate and realistic measuring results. Result: Wave-front aberration obtained from subjective visual compensation measuring method turned out to be smaller than objective measurement, which is the result of subjects’ adaptive correction when watching sighting targets. In addition, when subjects are watching different sighting targets, the fluctuation value of wave front aberration is small. Conclusion: Subjective visual compensation measuring method takes into consideration the actual condition of human eyes when watching targets which contributes to aberration measuring improvement and obtains results that match realistic state, all of which are of positive and beneficial value to the determination of human eye aberration treatment.
Analysis of the Milling Distortion Due to Residual Stress Based on FEM
Authors: Liu Yuan Wei
Published: October 2010

The key problems in 2D FEM simulation such as the establishment of finite element model, the initial stress loading, the distortion appraisal are solved and 2D FEM simulation model is built to analyze the milling distortion caused by the residual stress. The FEM model is verified by the elasticity theory. Some machining cases are simulated by using of the FEM model. The machining distortion caused by residual stress are analyzed and summarized using the simulation results.
Research of Thermodynamics and Properties of Pb/WC-Zro2 Inert Electrodes Used in Zinc Electrodeposition
Authors: Xu Rui Dong , Wang Jun Li , Zhou Jian Feng
Published: October 2010

This research is to fabricate a Pb/WC-ZrO2 inert electrode used in zinc electrodeposition. First, the potential-pH diagram of Pb-H2O system was constructed and the thermodynamic stable region was calibrated in the diagram. On the basis, the co-deposition of Pb, WC and ZrO2 particles from fluorboric acid solutions was realized on the surface of Pb-4wt%Sb substrate. The results show that deposition amounts of ZrO2 and WC particles in the inert electrodes increase with increasing ZrO2 concentrations in the bath, WC particle is easier to deposit into the inert electrodes than ZrO2 particle. The distribution of WC and ZrO2 particles as the second phase within metal matrix Pb is very uniform. Compared with Pb-1wt%Ag alloy electrode, Pb/9.91wt%WC-3.62wt%ZrO2 inert electrode possesses better catalytic activity of oxygen evolution.
Study on Influence Scope of Shock Wave and Smoke Flow after Gas Explosion
Authors: Qu Zhi Ming
Published: October 2010

Gas explosion is very disastrous accident all over the world. Influence scope analysis of shock wave and smoke after gas explosion is of great importance and significance. The results indicate that, during the process of shock wave propagation destroying the air throttle, the shock wave energy will be consumed as part of air throttle destruction, which causes the overpressure reduced. However, the shock wave continues to be propagated and attenuated to a certain distance. Results on analyzing influence scope of smoke flow show that the smoke temperature and concentration in roadway are higher before restoring ventilation. The smoke is diluted by the fresh air through diffusion. After restoring ventilation, the temperature and concentration of smoke flow are lowered greatly. In conclusion, the influence scope study of shock and smoke flow is of full practice.
Simulation and Experimental Investigations of Fiber Diameter of Spunbonding Nonwovens by Means of the Air Jet Flow Field Model
Authors: Zhao B.
Published: October 2010

The air jet flow field models of spunbonding process are founded. It is simulated by means of the finite difference method. The numerical simulation computation results of distributions of the air velocity match quite well with the experimental data. The air drawing model of polymer is solved with the help of the distributions of the air velocity measured by a particle image velocimetry. The predicted filament fiber diameter agrees with the experimental data well.
Fabrication of Biodegradable Polymeric Micro-Analytical Devices Using a Laser Direct Writing Method
Authors: Zhang W.W. , Zhu J.J. , Yung Winco K.C. , Ang Simon S.
Published: October 2010

Microfluidic channel and micro-cavities were fabricated from polyhydroxyalkanoate biodegradable polymer using a direct 20ns, 248 nm excimer laser writing method. First we give a design of the micro-analytical device; second we discussed the laser ablation of biodegradable ppolymer material. The morphology, dimensional accuracy, and surface conditions of the fabricated micro-devices were studied using atomic force microscopy, scanning electron microscopy, optical microscopy, and X-ray photoelectron spectroscopy. Melting of the biodegradable polymer was observed at a fluency of 50mJ/cm2 while ablation was observed at a fluency of 100mJ/cm2.The different width between bottom and top surface are studied in our research. The particle deposited on the polymer surface is seen from the SEM of 248nm laser ablation of PHA. However, the direct burning of PHA can be seen from the optical photo by 355nm laser. Compare to results of PHA with two different lasers, we can see that the 248nm laser is a suitable choice.
Research on Fabricating Technology of Three Dimensional Integrated Braided Composite I Beam
Authors: Pei X.Y. , Li Jia Lu
Published: October 2010

In this paper the fabricating technology of three dimensional (3D) integrated braided composite I beam is researched, including: braiding technology of 3D braided I beam preform, the orientation of fiber-tow in the I beam preform, the optimizing of process parameters of resin transfer molding (RTM) for 3D braided composite I beam, and the design of mould for consolidation of composite I beam. The quality of 3D braided composites is good analyzed by ultrasonic A-scan, void content calculation and microscope observation. The research result will provide a good way for designing and fabricating high performance 3D integrated braided composite components with irregular cross section.
Simulated Annealing Genetic Algorithm and its Application in Mixed-Model Assembly Line Design
Authors: Jiang Yan , Li Xiang Feng , Zuo Dun Wen , Jiao Guang Ming , Xue Shan Liang
Published: October 2010

Simple genetic algorithm has shortcomings of poor local search ability and premature convergence. To overcome these disadvantages, simulated annealing algorithm which has good local search ability was combined with genetic algorithm to form simulated annealing genetic algorithm. The tests by two commonly used test functions of Shaffer’s F6 and Rosenbrock show that simulated annealing genetic algorithm outperforms the simple genetic algorithm both in convergence rate and convergence quality. Finally, the simulated annealing genetic algorithm was firstly applied in a practical problem of balancing and sequencing design of mixed-model assembly line, once again, the solution results show that simulated annealing genetic algorithm outperforms the simple genetic algorithm. Meanwhile, it provides a new algorithm for solving the design problem of mixed-model assembly line.
Construction of Marketing Management Information System of Travel Agency Based on Customer Relationship Management
Authors: Wei M.
Published: October 2010

The theory of customer relationship management has been gradually penetrated into all levels of enterprise management. As a close business with customers, travel agency should focus on customer relationship management, which is very important. This paper attempts to combine the concept of customer relationship management and the processes of traditional travel agency marketing to construct the system architecture, considering the actual situation and specific requirements of a travel agency, combining with norms and standards of the management of travel agencies industry, as well as, using the current popular system architecture B/S (Browser/Sever) Mode. By extensively studying the theory of software engineering, database theory and object-oriented languages and Web programming, management information systems analysis and design process of travel agency marketing is discussed in detail based CRM.
Research on the Application of Fuzzy Neural Network in the Automobile Reliability
Authors: Men Yan Zhong
Published: October 2010

The data of engine failures about automobile operating in field conditions was collected by running engine failure tracking tests. An evaluative model was established using the theory of Fuzzy Neural Network (FNN) for the automobile “using reliability, based on the data of failures about automobiles, finally, the evaluative result for the automobile” using reliability was obtained by evaluative model of reliability. The result of research can be used as references for the improvement of reliability and maintainability of automobile engines, and for the establishment of maintenance strategy, and it also laid a theoretical foundation for studying the improvement of evaluation method for the automobiles' reliability as well.
A Multi Agent-Based Approach for Supply Chain Network
Authors: Wang Rui
Published: October 2010

This paper applies the multi-agent system paradigm to collaborative negotiation in supply chain network. Multi-agent computational environments are suitable for dealing with a class of coordination and negotiation issues involving multiple autonomous or semiautonomous problem solving agents. An evolution teamwork system based on multi-agents that can organize most team members in supply chain network was proposed. The proposed model performs adaptive development relying on differential evolution process. The experimental results show that our developing teamwork system is able to provide the adaptability of team differential evolution is global optimization and continuously develop teamwork members for the resources management in supply chain network.
Experiment Research of Cutter Edge and Cutting Parameters Influence on Machined Surface Roughness for High Speed Milling Hardened Steel
Authors: Zhang Wei , Zheng Min Li , Cheng Ming Ming , Wan Quan
Published: October 2010

By using experiment cutter edge topography obtained by super depth three-dimension microscope, fits the cutter edge curve and calculate experiment cutter edge radius value; by high speed milling hardened steel experiment, individually researches cutter edge and cutting parameters influence on machined surface in high speed milling hardened steel with end-milling cutter and ball-end milling cutter. The experiment analysis results show that under the same cutting parameters condition, machined surface roughness in high speed end-milling cutter milling is better than in high speed ball-end milling; within experiment selected cutting parameter range, cutter edge radius is the main influence factor on machined surface roughness in high speed end- milling hardened steel, while the influence on machined surface roughness in high speed ball-end milling hardened steel is not obvious. In end-milling, when edge radius and milling depth are in the same order magnitude or the difference is not obvious, milling depth should be a little bigger than selected cutter edge radius value.
Study on Laser Triangulation Measurement Principle of Three Dimensional Surface Roughness
Authors: Cui Feng Kui , Song Z.B. , Wang X.Q. , Zhang Feng Shou , Li Yan
Published: October 2010

The basic principle of three-dimensional surface roughness laser triangulation has been analyzed in this paper, Light-path diagram and optical geometric relationship of direct-type and symmetric oblique-type triangulation measurement is studied, the mathematical model of Surface micro-height information analysis is given. Resolution of direct-type and symmetric oblique-type triangulation measurement is compared both qualitatively and quantitatively. At last, the Application of laser triangulation method in Three-dimensional surface roughness measurement is analyzed.
Estimation and Display of Triangular Mesh Curvature in Reverse Engineering
Authors: Shen Hui Cun , Nie J.J. , Zong W.S. , Wang J. , Yang B.G.
Published: October 2010

The estimation of triangular mesh curvature is implemented by establishing local quadric surface at vertexes of mesh. Deduction course of quadric surface curvature calculation is presented. Errors and complexity of two curvature estimation methods, which are the ecumenical quadric surface fitting method and the quadric paraboloid surface fitting method respectively, are compared. Technique for curvature group display is put forward. This technique can display features of mesh distinctly, even though the curvature values of mesh distribute non-uniformly in their variety range.
Local Strain Hardening of Metal Components by Means of Martensite Generation
Authors: Behrens Bernd-Arno , Hübner Sven , Bouguecha Anas , Knigge Julian , Voges-Schwieger Kathrin , Weilandt Katrin
Published: October 2010

The emphasis, in respect of content regarding the here presented project, lies within the production of localized reinforcements, by means of transformation-induced α’ martensite formation in solid and sheet metal components. During the forming process of metastable austenitic steels, high-strength martensite areas, next to ductile austenitic regions, are to be adjusted to enable the production of load-adapted components.
To this end, extensive basic analyses are also necessary in order to determine the description of the mechanical behavior of α’-martensite structures, as well as to determine the extension of the numerical simulation as regards the structural change.
The results achieved within the area of steel forming include the development of a temperable deep-drawing die (T = -35 °C until T = 100 °C) that carefully facilitates structural conversion at a constant forming-degree. Moreover the crash performance, based on transformation-induced martensite structures is improved. So-called Forming Curves (FCs) were developed as a new approach towards the material characterization of structured steel.
In bulge forming components, comprised of chrome and nickel steels as well as manganous hard steel, martensite was specifically generated under the use of differing forming parameters. The tool design was aided by Finite Element Analysis (FEA).
Moreover, fundamental simulations were carried out in order to calculate the structural change. The modification and extension of a semi-analytical model of the material followed so that the martensite content could be calculated in the previously examined sheet components, as in the massive forming.
Investigations into Manufacturing Composite Profiles Having Local Magnesium-Foam Reinforcements
Authors: Plorin Tillmann , Bormann Dirk , Heidenblut Torsten , Bach Friedrich Wilhelm
Published: October 2010

Owing to their mechanical properties, metallic foams possess the outstanding ability to considerably improve a structure's stiffness and energy absorption capacity with low increases in weight. In the research results from the sub project A4 "Foam filled, rolled, closed profiles” of the CRC 675 "Creation of high strength metallic structures and joints by setting up scaled local material properties" introduced here, both the manufacture as well as the reinforcement of magnesium foams, which are produced by means of powder metallurgy, are described. The potential for increasing their strengths using reinforcements are demonstrated and the results of mechanical tests are presented. In addition to this, research results are presented which have contributed to achieving the main objectives of developing a combined technology for producing profiles which are locally reinforced using magnesium foam. The developed technology is characterised by integrating the foaming process into the roll forming process.
Laser Bead-on-Plate Welding and Overlap Seams for Increasing the Strength and Rigidity of High Strength Steel
Authors: Schimek Mitja , Herzog Dirk , Kracht Dietmar , Haferkamp Heinz
Published: October 2010

Nowadays, high requirements are being placed on producing lighter automobiles with a higher strength. To achieve graded strength properties and to improve the rigidity of high strength thin steel sheets, the side effects of laser joining processes can be used. Local physical and geometrical effects which have previously only been observed as side effects can be purposefully used to increase the rigidity and strength of sheet metal structures. By using a focused laser beam with a diameter of several tenths of a millimetre, bead-on-plate and overlap welding seams have been produced. The energy needed to produce this kind of welding seam can be limited to a small area of the workpiece. In comparison to other procedures, the basic material characteristics are retained after welding, the main reason for this being localized heat input. The continual development of laser beam sources to provide higher output powers has extended their spectrum of use in the field of joining technologies. One aim of the research is to produce local physical and geometrical effects with two different laser systems, on the one hand, with an Nd:YAG laser with a maximum output power of 4 kW, and on the other hand with a Yb:YAG laser with an maximum output power of 3 kW. Bead-on-plate and overlap welding seams were produced to demonstrate that rigidity and strength can be increased in metal sheets. The investigations were carried out on two high strength steels H340LA with two different zinc coatings (D and ZE) and TRIP700. The sheets were tested using tensile tests, 3-point bending tests and fatigue strength tests. During the tests, metallographic analyses were carried out. Seven different specimens were investigated, one without bead-on-plate welding seams, and six with different welding geometries, expect the material H340LAZE which was investigated with three various welding geometries. To analyse the complex stress status, investigations of the residual stress and the fracture were done. Calculations of the seam volume were done to be able to calculate the tensile strength for linear bead-on-plate welding seams and the maximum force for bending overlap welding seams. The tensile and bending tests showed that higher forces were needed before failure occurred, e.g. bending the specimens. Furthermore, the investigations showed that the strength of the specimens with welding seams increased, in comparison to the specimens without welding seams. Another result of the experiments is that there is a dependency between the fatigue strength and the position of the seam relative to the direction of the testing force.
Forging of Aluminium Components under a Superimposed Hydrostatic Pressure to Induce Local Strain Hardening
Authors: Behrens Bernd-Arno , Hagen Thomas , Klassen Andreas , Knigge Julian , Mielke Jens , Pfeiffer Insa
Published: October 2010

A promising approach to handling low ductile aluminium alloys in a forming process is forming under superimposed hydrostatic pressure. The influence of superimposed hydrostatic pressure on the flow stress as well as on the formability for various hydrostatic pressures and temperatures was analysed [15, 3, and 7]. By increasing the formability of the workpiece, larger local plastic strains could be achieved. The results reveal highly increased formability at superimposed pressure of 85 MPa for workpieces from thermosetting alloy AlSi1MgMn (EN AW 6082) in comparison to those from self-hardening alloy AlMg4.5Mn0.7 (EN AW 5083). As a general tendency, the self-hardening alloys show a lower increase in formability when forged under superimposed pressure. But additionally, a charge-dependent influence of macro- and micro defects on the crack resistance was detected for alloy AlMg4.5Mn0.7. By evaluating damage models in finite element models the damage occurring in cold forming processes under superimposed hydrostatic pressure was predicted.
Development of Combined Manufacturing Technologies for High-Strength Structural Components
Authors: Denkena Berend , Breidenstein Bernd , de Leon Luis , Dege Jan
Published: October 2010

Novel manufacturing technologies for high-strength structural components of aluminium allow a local modification of material properties to respond to operational demands. Machining and finishing processes for changing material properties like deep rolling or rubbing are to be combined to a single process step. The intention is the controlled adjustment of the component’s properties by the modification of its subsurface. For that purpose the essential understanding of the interaction mechanisms of the basic processes turning, deep rolling and rubbing is necessary. Influences of the tool geometry as well as of the process parameters on the material properties are investigated. The results will be extended by parameter studies within numerical simulations. Thereafter, combinations of the basic processes in process sequences are analyzed to their ability to modify the subsurface properties. In consideration of these results, a prototypic combined turn-rolling tool is developed
Investigation of the Process- and System-Induced Activation of Material Reactions during Discontinuous High-Frequency Welding
Authors: Wesling Volker , Schram Antonia , Wiche Henning
Published: October 2010

Besides weldable component geometries for the high-frequency welding process also possible process and system induced activated material reactions during discontinuous high-frequency welding are presented in this paper. Among others such material reactions can be a locally limited thermal influence on the base metal, defined plastic derformations during the upsetting process as well as grain refinement in the weld seam, comparable to thermomechanical treatment during rolling for increasing strength or ductility.
Optical Quality Control of High-Strength Structures
Authors: Denkena Berend , Möhring Hans Christian , Acker Wolfram , Zaretskiy Evgeny
Published: October 2010

High-strength structure components can be built by the application of an advantageously designed geometry. These structures are challenging to manufacture due to their complex shape. This motivates the design of a new system for quality assurance of the geometric properties of these structures. Firstly, different measurement approaches and their usability for the measurement of high-strength structure components are discussed. Then an optimized solution is suggested. A pattern projection method is introduced, whereas the patterns adapt locally to the measured surface. The basic object of the research are methods of the optic three-dimensional measurement of structural elements with the help of adaptable pattern projection that allows to adjust the measuring process to the local geometry and reflecting characteristics of structural elements. This technique takes care of the special properties of high-strength structure components within the production process. It is described, how a measurement speed can be achieved that can catch up with a common production frequency without interrupting the flow of the parts. Furthermore, the measurement can take place in an industrial environment, because it is relatively tolerant to movements of the measured structure. Therefore, the measurement procedure is divided into two steps. Within the adaptation-step the luminescence and the resolution of the projected pattern is adapted to the measured object. The actual picture is taken and calculated in a second step in order to be robust against vibrations. The result of the measurement is an optimized point cloud of several million points. The paper concludes with a description of the data processing procedures necessary in order to evaluate the correctness of the measured structure.
Fatigue Life Calculation Concepts for Structures with Locally Modified Properties
Authors: Medhurst Tim , Esderts Alfons , Masendorf Rainer
Published: October 2010

The influence of forming on the cyclic behaviour of various thin sheet metals with austenitic phases is looked into, with the main focus lying on the variation of cyclic parameters and the progression of work hardening over the materials’ fatigue life. There is a marked interaction of hardening due to increased dislocation density resulting from forming and hardening due to cyclic straining under varying strain amplitudes of strain controlled LCF testing. This is strongly dependant on the degree of forming and the amplitude of the following cyclic loading. Also, the temperature influence during forming of addtional forming elements in a temperature controlled die on the fatigue performance of austenitic and complex three phase steels was analysed, showing a marked influence of the forming temperature on the fatigue performance, enabling positive effects to be achieved by choosing suitable material specific forming temperatures.
Low Heat Joining – Manufacturing and Fatigue Strength of Brazed, Locally Hardened Structures
Authors: Wesling Volker , Schram Antonia , Kessler Mirjam
Published: October 2010

Low-heat brazing as a joining option for high strength steel sheets under cyclic load is still a challenge for manufacturing. For application arc brazing to locally hardened, high strength steel sheets a material specific manufacturing concept is needed to ensure a quality-related, reliable and reproducible processing. Thus the interaction of brazing parameters, metallurgical properties, types of brazed seams and different arc-processes under cyclic load were investigated. This should extinguish the base for an extended application of arc-brazed joints at cyclic loaded, high strength, property adjusted structures.
Use of the Aging Effect to Change the Local Properties of Structure Components
Authors: Asadi Mehdi , Schulze Nicole , Palkowski Heinz
Published: October 2010

This research deals with processes leading to local strengthening effects in Advanced High Strength Steels (AHSS). Dual phase (DP), retained austenite (RA) - both hot and cold rolled - and complex phase (CP) steels have been investigated to examine the effect of thermal and mechanical processing parameters on local properties. For this purpose, a method has been investigated to achieve local strengthening, namely local deformation and local heat treatment. Samples were locally deformed by bending and embossing processes. A local deformation with defined pre-strains leads to enhanced hardness and strengthening. A subsequent aging treatment leads to a further increase in mechanical properties. Local heat treatment was applied using a laser and an electron beam. Following local heat treatment with selected parameters, the microstructure of the surface and the cross section as well as the mechanical properties were evaluated by light optical, scanning as well as transmission electron microscopy, hardness measurement, tensile testing and thermal modelling. It can be stated that with partial heat treatment, local high strengthening can be produced. At lower heat treating temperatures, this effect could be attributed to bake hardening. With increased heat treating temperature, the initial microstructure near the surface is affected. A model can be improved, which defines the correlation between the influencing parameters and the local properties. The influence of over-aging in locally strengthen regions has been studied. For this investigation, parameters are stable to locally adjust the strengthening effect. Partial strengthening of AHSS by local deformation or local heat treatment can open up new fields of applications for locally using the strengthening effect to only influence relevant areas of interest, thus providing the potential for saving energy and designing the component’s behaviour.
Setting of Gradient Material Properties and Quality Control of High Tension 3D NVEB-Weld Joints
Authors: Diebel Melanie , Mroz Gregor , Frackowiak Wojciech , Hauer Jasmin , Reimche Wilfried , Bach Friedrich Wilhelm
Published: October 2010

In modern, highly loaded structures of metallic materials, particular standards are required both regarding the strength and deformation properties of individual components as well as in terms of the load carrying capacity of the bonded joints between individual components. This specific subject matter is taken up in the subproject C4 "Setting of Gradient Material Properties and Quality Control of High Tension 3D NVEB-Weld Joints" within the framework of “Collaborative Research Centre” CRC 675 "High strength, locally modified components and structures" in order to correspondingly and individually adapt a component's properties to the loading profile. For this purpose, components having specifically calibrated strength properties are joined into high quality structures. Although still quite new but powerful, and due primarily to its very favourable welding characteristics, the non-vacuum electron beam welding technology is, in this case, to be further developed with respect to an improvement in beam positioning and weld-seam defect inspection.
On the other hand, a well-defined, local heat-treatment is to be carried out on individual, work-hardened components to be able to introduce targeted and structured local, load-oriented microstructural changes into the component: thereby locally changing the component's strength and deformation properties with a view to retarding crack growth.
Systematic Design Approach to the Development of High-Strength, Locally Adapted Structures with the Aid of the Finite Element Design (FED) Method
Authors: Lohrengel Armin , Wesling Volker , Schäfer Günter , Schram Antonia , Bessling Sara , Echtermeyer Pierre , Stahr Konrad
Published: October 2010

Design engineers can choose from a large variety of materials in order to fulfill a certain function. In those fields of application with a lower level of complexity, it is often sufficient to manufacture the entire component in a “monolithic” manner from one single material. Concurrent, partly contradictory and, most probably, local requirements that must be fulfilled by a component often make material selection more difficult. As a consequence, it is often necessary to use several different materials with a local and functional orientation, which is a part of the multi-material design strategy. The potential of different materials can be used most effectively if this information is made available to the design engineers as early on in the design process as possible. The aim of the SFB 675 sub-project C7, therefore, is the development of a systematic design approach (Finite Element Design, FED) that focuses on finite component elements. As a result, the potential of the optimization of local properties is taken into consideration, and the interaction between the materials, production processes, and design can all be described.
Acoustic Measurements to Proof High-Strength Structures and Joints
Authors: Lohrengel A. , Thoden Daniel , Schäfer Günter
Published: October 2010

Due to increased product requirements, usual conditions for materials cannot be applied anymore. To reduce energy consumption, lightweight constructions are demanded but they cannot stand necessary mechanical stress. Therefore, local reinforced elements are applied for instance. According to actual research in material sciences, it is prerequisite to verify the position of this strengthening. Various physical principles can be used for non-destructive testing of this effect. In this article, an approach based on acoustic signals is presented. On the one hand a strategy could be to do comparative studies between nominal and sample and on the other to predetermine the place just by acoustic parameters like eigenmodes. In preliminary test, vibration characteristics of these innovative materials (e.g. bake-hardening plate and sandwich structure) are determined and reveal capabilities for acoustic methodologies. So, this approach could be a promising tool to localize reinforced elements.
Production of Customized High-Strength Hybrid Sandwich Structures
Authors: Sokolova Olga , Carradó Adele , Palkowski Heinz
Published: October 2010

The production process and the forming behaviour of locally reinforced steel/polymer/steel (316L/PP-PE/316L) hybrid sandwich composite materials (SMS) have been investigated. The effect of simple plate reinforcements with different size, shape and geometry on the forming limits of SMS was studied. As a local reinforcement, the simple solid steel and mesh steel plate inlays with central and edge positions were chosen instead of a polymer core as a sandwich laminate. In order to increase the adhesion properties between the metal and polymer layers, corona discharge and plasma preliminary surface treatments were applied prior to the sandwich production.
Both, deep drawing and stretching cup-forming tests were performed in order to analyse the forming behaviour as well as the failure of SMS with and without local inlays subject to different tensile loadings. The influence of the local reinforcement on the bending behaviour was determined by three and four-point bending processes. Stress-strain curves and thinning behaviour of SMS with local reinforcements under the different forming loads were determined using digital image correlation via photogrammetry.
The forming behaviour strongly depends on the quality, geometry and size of the local plate inlays. Owing to the different positions of reinforcement as well as to the different polymer content around of inlays, failure of SMS by bending and drawing differs. The sandwich samples with mesh reinforcement demonstrate better formability by drawing and bending than that of samples with solid plates. In order to minimise the loss in formability of sandwich samples during deep drawing, the size of the centred reinforcement has to be larger than the punch diameter.
Enhancing the Localized Corrosion Resistance of High Strength 7010 Al-Alloy
Authors: Kannan M. Bobby , Raja V.S.
Published: October 2010

This paper brings out the developments on heat-treatment and alloying to improve the stress corrosion cracking (SCC) behavior of 7010 Al-alloy. The role of microstructures including the grain boundary precipitates and recystallized grains and the relation of intergranular corrosion (IGC) on the SCC behavior of 7010 Al-alloy have been discussed.
Understanding Nanoscale Wetting Using Dynamic Local Contact Angle Method
Authors: Losada Martin , Mackie Katherine , Osborne Joseph H. , Chaudhuri Santanu
Published: October 2010

A multiscale quantum/classical-framework for hydrophobicity and UV absorption in heterogeneous coatings is presented. Atomistic water droplet simulations on coated oxide surface are used to define nanoscale contact-angles using a new numerical technique called the dynamic local contact angle (DLCA) method. The DLCA method is well suited to calculate macroscopic contact angles for polymeric and composite coatings. The accuracy of the method is tested for a series of common polymers and composites. In addition, the sensitivity of the contact angles towards functional groups and nanoscale roughness are tested using varying molecular structures. Fluorinated polyhedral oligomericsilsesquioxanes (F-POSS) molecular frameworks are used as a model system. Changes in contact angle and UV absorption spectrum as a function of hydrophobic chain length are calculated to test the feasibility of developing a virtual framework for new coating design connecting atomistic calculations to continuum level material properties.