bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Cyberwar’s Synthetical Ability Based on TOPSIS Method
Authors: Tian Jia Ping , Cao Su Na , Du Jia Xing , Chen Ping , Zhan Huan
Published: August 2014

A evaluation of cyberwar’s synthetical ability based on TOPSIS method is discussed in this article. The method is a technique for order preference by similarity to ideal solution which can avoid the difficulty in traditional evaluations that regard the multi-evaluation parameters as a single efficiency evaluating value. The article supply a new idea to the evaluation of cyberwar’s synthetical ability.
Study on the Feeder Selection Method for 10kV Regional Compensation Type Dynamic Voltage Restorer
Authors: Zhang Hua Ying , Yao Sen Jing , Zhu Zheng Guo , Cao Jun Wei , Liu Yang
Published: August 2014

This paper proposes the designing of regional compensation type Dynamic Voltage Restorer (DVR), and the topology of main circuit, the detection algorithm for voltage sag, the calculation method of reference voltage and pulse modulation method. Based on the different load types of the target substation and the sensitivity to voltage sags, the selection principle of the location of compensation line for regional compensation DVR is proposed, and the realization of substation feeder selection method is illustrated by taking a substation as an example. The compensation effect of the DVR under different fault types are simulated, and the validity and rationality of the designing are verified.
Analysis of Key Technology of NC Turning Machining
Authors: Tian Cun Xia
Published: August 2014

Through the process of NC machining analysis, summed up the points of NC machining process analysis, through the process of a comprehensive and reasonable analysis procedure for CNC turning and CNC programming formulation provides an important basis and guarantee, so as to improve the machining quality and the machining accuracy requirements.
Fixtures Design Based on RP Technology
Authors: Zhang Zheng , Li Dan Tong , Deng Jia Wen , Huang Ming Yu , Wan Xiao Feng , Wu Qiang , Zhou Yi Dan
Published: August 2014

In the mechanical processing, fixture has an irreplaceable role, but in the traditional design methods, there are many shortcomings, the rapid prototyping technology is used in the design of fixture was mainly introduced. The defects of fixture design was introduced at this stage, the rationality of rapid prototyping technology used in fixture design was analyzed, then, the advantages of rapid prototyping technology used for fixture design was highlighted, through the concrete example and the forming process of display.
Milking Controller Design Based on Infrared Communication
Authors: He Ping , Li Ying , Gu Guo Lei , Wang Meng
Published: August 2014

The automation of dairy farms attaches great importance in developed countries. They implement many preferential policies, technical and economic measures to prompt new automatic equipments , so as to reach a new stage of dairy farm development. Intelligent automatic milking controller has been applied widely and maturely in foreign countries whereas it falls behind relatively in our country. Along with the development of the information technology, it will be an irresistible trend of dairy farms to realize the digital management. The controller which is the core equipment of automatic dairy farm is studied in this paper. The controller uses the AVR microcomputer as its core and the software programming uses the C+ + language. This controller can also realize the infrared data communication with the higher computer. With the characteristics stood above, the controller can be applied to the existing milking machines of the dairy farm and it has a wide application prospect.
Simulation Research of Switching Power Supply Based on CMAC and PID Compound Control
Authors: Fang Jian Hua , Wang Jin Quan , Xu Ye , Hou Peng Fei
Published: August 2014

As a high-performance switching power supply, DC power supply is widely used in the micro grid involving new energy generation. In this paper, for the strongly nonlinear BUCK circuit (switching power supply), the cerebellar model articulation controller (CMAC) and PID compound control algorithm is proposed to achieve nonlinear system control. By using MATLAB/Simulink simulation study, results show that the system has better steady-state and dynamic performance.
Research Progress in Diamond Cutting Tool Materials and Preparation Technology
Authors: Ma Gai , Wu Qiang , Ni Hong Jun , Zhou Yi Dan
Published: August 2014

High temperature and high pressure (HTHP) and chemical vapor deposition (CVD) are two important methods of preparing diamond. This article briefly introduced the kinds of diamond cutting tool materials and the two technologies of synthesizing diamond. And in the end, the developing trends of diamond cutting tool materials and the preparation technologies were forecasted.
Mechanical Properties of MWCNT Modified Syntactic Foams with High Volume Fraction of Glass Microspheres
Authors: Drdlová Martina , Frank Michal , Buchar Jaroslav , Krátký Josef
Published: August 2014

The effect of multi-wall carbon nanotubes content on physico-mechanical properties of glass microspheres-epoxy resin syntactic foam was evaluated experimentally. Syntactic foam with high volume fraction of microspheres (70 vol%) was prepared and modified by 1 to 5 vol% of multi-wall carbon nanotubes. The compressive, flexural and impact strength tests were conducted, the load-displacement curves were captured. The quality of dispersion of nanoparticles was evaluated in relation to the mixing procedure using scanning electron microscope observation.
Utilization of Bottom Ash for Sintered Artificial Aggregate
Authors: Černý Vit
Published: August 2014

At present high temperature fly ashes are already quite widely used as a secondary raw material in building materials. Fly ashes are usually able to fully replace classical materials. FBC ashes also gradually finding their place for example in production of autoclaved aerated concrete, in binders or solidification of hazardous waste. However, the coarser types of energy by-products are relatively difficult to use. Therefore, this part of the work focused on the study of usability of bottom ashes for artificial sintered aggregates. The article will focus on results of laboratory firing in muffle furnace, dedicated to testing of maximum bottom ash content in the mixture with the fly ash and special type of clay.
Characterization of Thermal Stress of Building Materials Containing Rubber Granulate by Alternating Electric Field
Authors: Kusák Ivo , Lunak Miroslav , Chobola Zdeněk , Tupý Michael , Sotiriadis Konstantinos
Published: August 2014

The present paper deals with the application of impedance spectroscopy method to test cement-based composites after their exposure to high temperatures. A type CEM I Portland cement, siliceous sand and shredded automobile tires were used to prepare mortar specimens. The specimens differentiated in whether or not a 10 % w/w acrylic polymer binder (polymer dispersion 20 % w/w to cement mass) addition to the mortar mixture was used. The specimens were exposed to high temperatures (temperature range: 25-400 °C). Monitoring of structural changes during subjection to thermal stress is an effective way to determine the reliability of specimens structure. Based on Debye's dielectric theory, the specimens were used as dielectric models. Impedance spectra were obtained, while relative permittivity, loss factor and impedance were also measured. The results concerning electrical parameters and permittivity at each temperature were an indicator of the structural changes and its reliability.
Effect of Titanium-Dioxide-Enriched Nanotextiles on Cementitious Composite Exposed to Severe Environmental Conditions
Authors: Bily Petr , Kohoutková Alena , Ryparová Pavla , Rácová Zuzana
Published: August 2014

Photocatalytic cement containing titanium dioxide nanoparticles (N-TiO2) is commercially available for some 10 years already, but its wider utilization is limited by economic aspects. A new approach to implanting N-TiO2 into surface of cementitious composite exposed to severe environmental conditions was investigated. Polyvinyl alcohol (PVA) nanotextile containing N-TiO2 was prepared on Nanospider device. Photocatalytic properties of specimens made from ordinary white cement with surface covered by PVA nanotextile containing N-TiO2 were compared to the properties of reference samples made from ordinary white cement and samples made from commercially available photocatalytic cement. Although the PVA nanotextile containing N-TiO2 was not found to be a prospective solution for photocatalytic finishing in this stage of research, the idea of treating concrete surfaces with enriched nanotextiles was examined and will be further pursued as a very promising research topic.
Hydration of Calcium Aluminate Phases at Different Temperatures
Authors: Koplík Jan , Tomala Libor , Novotný Radoslav
Published: August 2014

Mayenite (C12A7) and calcium dialuminate (CA2) are both components of Calcium aluminate Cement (CAC). The hydration of these phases depends on initial conditions especially on the temperature. Pure phases were synthesized by solid-state reaction. The hydration was carried out at three different temperatures – 20 °C, 30 °C and 60 °C. The course of hydration was investigated by isothermal calorimetry. The results prove, that higher temperature increase reactivity of phases and decrease their initial period of hydration. The X-ray diffraction analysis (XRD) identified the hydration products of CA2 as katoite (C3AH6) and gibbsite (AH3). The hydration products of C12A7 depends on the temperature. At 20 °C the major products are C2AH8 and CAH10. At 30 °C CAH10 disappears and only C2AH8 remains. At 60 °C the only stable hydrates – C3AH6 and AH3 are formed.
Non-Destructive Acoustic Testing of High-Temperature Degraded Composite Cementations Materials Containing Rubber Aggregates and Ethylen Vinyl Acetate Polymer Binder
Authors: Štefková Daniela , Tupý Michael , Sotiriadis Konstantinos , Šamárková Kristýna , Chobola Zdeněk
Published: August 2014

The use of impact-echo acoustic method to test cement-based mortar composites modified with rubber aggregates and EVA polymer binder and degraded at high temperatures was studied. The specimens were prepared by using a type CEM I Portland cement and siliceous sand, as well as by substituting 25% of sand with shredded automobile tires and by adding EVA polymer binder (10% w/w to cement mass). The specimens were subjected to high temperatures (200-400 °C). The results of non-destructive testing confirmed the different structure of mortar specimens. The partial substitution of sand with rubber aggregates led to absorption of lower frequencies as compared to the reference specimens. A significant decrease of the absorbed frequencies was observed, depending on temperature. The largest decrease occurred after the specimens exposure at 200-300 °C. The effect of heat exposure to the decrease of frequencies was mitigated when the EVA polymer was used.
Synthetic Preparation of Ettringite
Authors: Fridrichová Marcela , Dvořák Karel , Kulísek Karel , Masárová Alexandra , Havlíčková Kateřina
Published: August 2014

This work is the opening chapter of the study that deals with products of degradation, which might form in hardened cement paste after exposure to sulphate attack. The article deals with ettringite preparation design and then with the realisation of this design
Treatment Sewage Sludge with the Addition of Charcoal
Authors: Hybská Helena , Ďuricová Anna
Published: August 2014

Wastewater treatment is an important human invention that facilitates the support and development of human civilization. The actual biological wastewater treatment, like most other technologies, is not waste-free technology, because produces a significant amount of waste, sewage sludge. It can therefore be concluded that technological processes for wastewater treatment in one hand bring the desired effect, namely treated wastewater, and on the other hand, unwanted product - sewage sludge. Simply we can say that the pollution, which was covered in water, the treatment of wastewater transferred to the birth of sewage sludge, in waste production [1].
Effect of Natural Ageing on the Physical Properties of Polypropylene Composites
Authors: Krzyżak Aneta , Prażmo Jakub , Kucharczyk Wojciech
Published: August 2014

The present work investigates the effect of natural weathering on polypropylene (PP) composites containing short glass fibers and talc. The samples of PP composites obtained by injection moulding were submitted to nine months of natural ageing (from March to November 2012). It observed effects of climatic conditions on some physical properties such as hardness, longitudinal and transverse shrinkage as well as plastic and elastic deformations.
Bicomponent Fibers for the Preparation of a New Effective Filtration Materials for Separation of Hazardous Chemicals in Technological Processes of Wood Treatment
Authors: Ružinská Eva , Krajewski Krzysztof J. , Mitterová Iveta , Zachar Martin
Published: August 2014

The paper deals with to evaluate the preparation and properties of polymer blends and fibers prepared from new type of synthetic fibres (bicomponent PP/PA6 with addition of interfacial agent MAH) for the purpose of subsequent production of a highly efficient filter for collection of particulate matter (dust) and aerosols of hazardous chemical (VOCs) in processes surface finishing and treatment of wood and wood products, in order to achieve the required hygiene and ecological characteristics and with a view to the protection of air and the working environment.
Char Layer of Various Tree Parts from Selected Coniferous Wood
Authors: Osvaldová Linda Makovická , Osvald Anton , Kačiková Danica
Published: August 2014

In the paper there is compared wood char layer of various tree parts (branches, trunk, roots) from pine, fir, spruce, larch. The samples were thermally loaded by the radiating source. The course of thermal degradation was evaluated by the char laye. The obtained results showed the influence of tree parts and wood species on calculated fire technical parameters. The values of char layer of wood from branches were the lowest. The char layer of trunk wood was the highest in case of spruce.
Mathematical Modelling of Temperatures in Airways during a Fire with Effects on Evacuation of Persons
Authors: Kučera Petr , Bradáčová Isabela , Dudáček Aleš , Vlček Vladimír
Published: August 2014

The contribution presents two basic variants of fire compartmentation. A conservative standard design is confronted with an atypical design supported by the mathematical modelling of temperature field. In both the cases, the required level of safety is ensured. The atypical design in this case enables the use of more available and economically profitable products ensuring the fire safety of the structure.
The Granularity of Dust Particles when Sanding Wood and Wood-Based Materials
Authors: Očkajová Alena , Stebila Ján , Rybakowski Marek , Rogozinski Tomasz , Krišták L'uboš , L'uptáková Jana
Published: August 2014

The article presents results of the granulometric composition of chip particles when sanding wood (beech) and wood-based materials (particleboard and semi-hardboard) using different types of sanders – wide belt sander, narrow belt sander, and hand sander. On the basis of the carried out sieve analyses, the proportion of produced particles, which can be marked as dust with the particle size of ≤ 80 μm, is high at the interval from 89.21% - 96.29 %. The highest percentage of dust particles was reached at dust from the hand disk sander. At the end of the article we point to possible technical safety measures – additional dust exhausting, suction, to possibly reduce the dust getting to the working environment.
Environmental Friendly Degradation of Atrazine by Ozone and Identification of Main Degradation Products
Authors: Šudý Marián , Balog Karol , Soldán Maroš
Published: August 2014

The present study investigates the degradation of atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine) by ozone and OH radicals during ozonization with the identification of the main degradation products after ozonation. The identification of main degradation products during atrazine degradation process was conducted by gas chromatography–mass spectrometry (GC–MS).
Identification of the Security Environment Influences on Renewable Energy Sources and Critical Infrastructure Elements of Euroregion Beskydy
Authors: Vidriková Dagmar , Boc Kamil
Published: August 2014

This article deals with security significance of environment on the critical infrastructure elements at the regional level. It divides it into external and internal environment. It identifies basic relevant influences that significantly impact development of activities of the society that functions within the environment. The article highlights the link between security risks and economic activities, as well as their reciprocal influence, including critical infrastructure elements at the regional level. Similarity of geographical conditions in Euro-region Beskydy also creates favourable conditions for investments into renewable energy sources. In recent years, however, these objects are the target of criminal attacks. Therefore, when deciding where to locate these objects need to build upon the security environment analysis of their wider surroundings and security risks. It illustrates by example on Euro-region Beskydy possible analysis of mutual relationship between security environment and development of individual regions. It is based on analysis of similarities of condition that potentially influence economic activity of both whole region and its individual national regions. Second part of the article contains proposal of possible procedure and content of the security analysis for the purpose of identification of those security risks that origin in the environment of the critical infrastructure elements at the regional level, and which have causal effect on its economic development. Therefore, the aim of this article is focused on the impact of crime in different parts of the territory of Euro-region Beskydy at the national as well as transnational level. At present, the importance of the critical infrastructure elements rises, already at the European, national or regional level. It is expected that these elements will be exposed to more significant impact and to action of crime from the enxironment.
New High Strength and Heat Resistance Aluminum Alloy Material for Engine Cylinder Head
Authors: Li Jin Lei , Su Yong , Ma Teng Di , Wang Qin
Published: August 2014

The effect of Cu、Ni、Fe、Mn on the mechanical properties of Al-Si alloy by orthogonal experiment method was investigated in this paper. By tensile testing and microstructure analysis, the content Ni element is 1% under the condition of Cu. The addition of Fe can improve high temperature strengthening of the alloy. However, we need to control the ratio of Fe and Mn to prevent the appearance of β phase, and reduce herringbone Fe phase. The best content of Cu、Ni、Fe、Mn is 1%,0.7%,0.9% and 0.5%. Thus the alloy’s room temperature and high temperaturetensile strength reaches 249MPa and 212MPa, fully meet the requirements of high-temperature load of the cylinder head.
Poly Acrylic Acid Superabsorbent Hydrogel for Hygiene Materials
Authors: Cui Hong Wei , Wen Shi Miao , Zhuang Ting Ting , Bai Fu Chen , Yu Li
Published: August 2014

Poly acrylic acid (PAA) was synthesized by solution polymerization. We analysed that MBA dosage, acrylic acid percentage, neutralization degree and surface crosslink have affections on PAA, mainly about three properties (including 0.9%NaCl solution's absorptivity, absorptivity under 2068Pa, and holding ability of moisture). The experimental evidence obtained that lower acrylic acid percentage is helpful to these three properties. Indexes increase at first and then decrease with neutralization degree raise. MBA dosage is against to absorptivity and retention capability, but useful to absorptivity under pressure. Scanning electron microscopy (SEM) was used to observe the surface of the PAA powder, and prove that surface crosslink promote form a kind of honeycomb structure. Under the optimum synthetic conditions, the absorptivity of 0.9%NaCl solution is 58.8 times, retention capability is 38.4 times, and absorptivity under 2068Pa is 33.6 times.
Study on the Relativity between Intrinsic Coercivity and Microstructure of the Nd-Fe-B Magnet Treated by the Optimized Aging Process
Authors: Ding Xia , Wang Xiao Li , Si Cong Hui , Zhao Li Na , Ding Kai Hong , Cui Sheng Li , Sun Yong Cong , Li Mu Sen
Published: August 2014

In order to increase the intrinsic coercivity of the Nd-Fe-B magnets, the aging process optimization had been carried out. The results showed that more than 17 kOe intrinsic coercivity could be obtained by the aging process optimization. The microstructures and the fractures of the Nd-Fe-B magnets treated by the optimized aging process were also investigated by optical microscope, thermal field emission scanning electron microscopy and energy disperse spectroscopy. It was showed that the thin, continuous and smooth Nd-rich layer along the boundaries of the main crystal phase Nd2Fe14B could be formed by the optimized aging treatment and it resulted in the increase of the intrinsic coercivity of the Nd-Fe-B magnets.
Comparison of Solvent-Casting and Melt-Compounding Blended Biomedical (Polylactide)-(Polyethylene Glycol) Mixture as Drug Carrier
Authors: Jiang Hong , Wang Li Bo , Xu De Jun , Liu Xiao Yang
Published: August 2014

For the purpose of drug carrier and delivery, the polylactide was modified by polyethylene glycol blending with the weight percentage of 80/20 by two methods: solvent-casting and melt-compounding. Characterizations of X-ray diffraction, Scanning Electron Microscope and degradation experiments have been done to study the crystallization, miscibility and degradation behavior. The melt-compounding provides a better miscibility associated with longer degradation time, however the heating procedure effects the polymers. Because of the heating and cooling cycle, the polymers had an opportunity to crystalize and the crystal peak can be seen in the XRD results. While the solvent-casting avoids the high temperature experience of blend with an amorphous state, and provides lower miscibility and short degradation time. These significant features will be considerable factors in drug carrier design.
Influence of Morphological Texture on Stresses Analysis by X-Ray and Neutron Diffraction: Accounting for Extreme Morphologies
Authors: Hounkpati Viwanou , Fréour Sylvain , Gloaguen David , Legrand Vincent
Published: August 2014

This work investigates, by diffraction methods, the morphological texture influence on the residual stress analysis in polycrystals having cubic or hexagonal symmetries. Different extreme crystallite morphologies (sphere, disc and fiber, with their principal axes aligned along common directions) were considered in the present study. In a second part, crystallographic textures were accounted for, also, enabling to reflect the combined effect of the simultaneous occurrence of morphological and crystallographic textures. A stronger influence of morphological texture than that of the crystallographic texture in terms of stresses was observed. The main purpose of this work is to make the best choice of lattice planes (hkl) used for residual stress analysis, in elasticity, depending on the morphological (and crystallographic) texture of the polycristal.
Study of Mechanical Behaviour of Polycrystalline Materials at the Mesoscale Using High Energy X-Ray Diffraction
Authors: Baczmański Andrzej , Gadalińska Elżbieta , Wroński Sebastian , Braham Chedly , Seiler Wilfrid , François Manuel , le Joncour Lea , Panicaud Benoit , Buslaps Thomas , Yahyaoui Houda , Sidhom Habib , Zhao Yu Chen
Published: August 2014

Owing to its selectivity, diffraction is a powerful tool for analysing the mechanical behaviour of polycrystalline materials at the mesoscale, i.e. phase and grain scale. In situ synchrotron diffraction (transmission mode) during tensile tests and modified self-consistent elastoplastic model were used to study elastic and plastic phenomena occurring in polycrystalline specimens during deformation. The evolution of stress for grains which belong to different phases of duplex stainless steel and pearlitic steel was analyzed.
Residual Stress Tensor Distributions in Cracked Austenitic Stainless Steel Measured by Two-Dimensional X-Ray Diffraction Method
Authors: Saito Youichi , Tanaka Shunichiro
Published: August 2014

The residual stress tensor for cracked austenitic stainless steel was measured by a two-dimensional X-ray diffraction method. Higher von Mises equivalent stress concentrations, attributed to hot crack initiation, were obtained at both crack ends. The stress of 400 MPa at the crack end in the columnar grain region was about two-fold larger than that of 180 MPa in the equiaxed grain region. This difference was caused by a depression in the cast slab.
Tailored Mechanical Properties and Residual Stresses of a-C:H:W Coatings
Authors: Schmid Christoph , Hetzner Harald , Tremmel Stephan , Hilpert Felix , Durst Karsten
Published: August 2014

In this study, three different a-C:H:W coatings with predefined hardness values, ranging from 10 up to 16 GPa, were deposited by adjusting bias voltage according to a previously created regression model. For this purpose, the influence of the main process parameters of the used reactive unbalanced magnetron sputtering process on the mechanical properties of the a-C:H:W coating was investigated previously by nanoindentation. For a systematical evaluation of the single effects, parameters were varied according to a central composite design. The three coating variants of this study were investigated in terms of microstructure, mechanical properties and residual stresses. It turned out, that by the use of the regression model, a-C:H:W coatings with tailored mechanical properties can be deposited. Residual stresses were measured by means of focused ion beam milling of a double-slit geometry, which causes the internal stresses to relax, and mapping of the resultant relief strain by digital image correlation. A linear relation between the applied bias voltage and the hardness, the modulus of the coating as well as the determined relief strain was observed. Thus, residual stresses of the coatings increase disproportionately with applied bias voltage. The obtained results can be helpful for tailored coating design and further optimization of a-C:H:W coatings.
Determination of Stress Profiles in Expanded Austenite by Combining Successive Layer Removal and GI-XRD
Authors: Pires Fernandes Frederico Augusto , Christiansen Thomas L. , Somers Marcel A.J.
Published: August 2014

The present work deals with the evaluation of the residual-stress profile in expanded-austenite by successive removal steps using GI-XRD. Preliminary results indicate stresses of several GPa's from 111 and 200 diffraction lines. These stresses appear largest for the 200 reflection. The strain-free lattice parameter decayed smoothly with depth, while for the compressive stress a maximum value is observed at some depth below the surface. Additionally a good agreement was found between the nitrogen profile determined with GDOES analysis and the strain-free lattice parameter from XRD.
Spatial Convolution of a Stress Field Analyzed by X-Ray Diffraction
Authors: Kahloun Charlie , Badji R. , Queyreau S. , Franciosi P. , Bacroix Brigitte
Published: August 2014

X-ray stress analysis suffers from homogeneity limitations of the stress field in the analyzed volume. When this homogeneity is not fulfilled, it is possible to reduce the irradiated volume down to stress homogeneity achievement. New limitation however occurs : the diffracting sites become too few for stress homogenization. We show that the diffractometry analysis corresponds to a spatially convoluted stress field. The inverse convolution problem is posed. An example of regularization method is given.
Residual Stress State in Oxide Dispersive Steel due to Irradiation by Swift Heavy Ions
Authors: Uglov Vladimir V. , Skuratov Vladimir A. , Ulyanenkova Tatjana , Benediktovitch Andrei , Ulyanenkov Alexander , Zlotski Sergey
Published: August 2014

Oxide dispersive steel is a promising material for next nuclear reactors generation. Performance of this material in nuclear reactor can be modeled by means of irradiation by swift Bi ions, which are typical nuclear fusion products. Radiation damage results in microstructure alternation leading to formation of micro and macro stresses that influence the material performance. The residual stress state of ferrite matrix of the steel is investigated by XRD methodic and dependence on the irradiation dose is analyzed.
Residual Stress Measurement with Laser-Optical and Mechanical Methods
Authors: Martínez-García Venancio , Wenzelburger Martin , Killinger Andreas , Pedrini Giancarlo , Gadow Rainer , Osten Wolfgang
Published: August 2014

A new approach in hole-drilling residual stress analysis is described, applying a laser for quasi non-destructive material removal by laser ablation and measuring simultaneously the residual deformation around the hole by means of high-resolution, digital holographic interferometry. To evaluate this technology, experiments measuring well-defined in-plane stresses in curved strip specimen, on experimental bending device based on the European Standard for four-point bending tests, were carried out with the conventional hole drilling and milling technique and the laser-optical technique described.
Combining XRD with Hole-Drilling Method in Residual Stress Gradient Analysis of Laser Hardened C45 Steel
Authors: Kolařík Kamil , Pala Zdenek , Ganev Nikolaj , Fojtik Frantisek
Published: August 2014

LLocalized laser hardening of steel surfaces performed with optimal parameters not only hardens the surface layer, but is also capable of generating advantageous hook-like shape of residual stress depth distribution. Upon combining two most common methods of XRD and hole-drilling, the residual stresses up to the depth of 3 mm were analysed for two widths of high-powered diode laser beam. Narrower laser beam generates wider area with compressive stresses and the diffraction technique as compared with hole-drilling method always indicates higher values of compressive residual stress maxima.
Strain Measurement with Nanometre Resolution by Transmission Electron Microscopy
Authors: Cooper David , Rouviere Jean Luc
Published: August 2014

Strain is routinely used in state-of-the-art semiconductor devices in order to improve their electrical performance. Here we present experimental strain measurements obtained by different transmission electron microscopy (TEM) based techniques. Dark field electron holography, nanobeam electron diffraction (NBED) and high angle annular dark field scanning electron microscopy (HAADF STEM) are demonstrated. In this paper we demonstrate the spatial resolution and sensitivity of these different techniques on a simple calibration specimen where the accuracy of the measurement can easily be assessed.
A Measuring and Evaluation Program for the Application of the Ring-Core or Hole-Drilling Method
Authors: Nau Andreas , Scholtes Berthold
Published: August 2014

There is a strong need for reliable residual stress measurements. On the one hand, residual stresses can be beneficial, when they are adapted to external loads. On the other hand, they can be detrimental, when they are unknown. Thus, their occurrence can lead to an uneconomical oversizing of components or in their failure, as well. Apart from diffraction methods, mechanical methods are well recognized in order to determine unknown residual stress states. Depending on the applied method, specific boundary conditions have to be taken into account. In the case of mechanical methods like the hole-drilling and the ring-core method, the characteristics of the geometry of the component should be in accordance with an ideal and thick plate. The reason behind is the need for a calibration data set to transform strains into stresses. The calibration is usually carried out numerically. For the sake of simplicity, the geometry of the component is an ideal thick plate and the hole is introduced in its center. However, in most cases, this is not identical with the geometry of the component under investigation. Hence, an application tool was designed that enables the parametric design of a Finite Element Model, the determination of calibration coefficients, the evaluation of the experiment and the visualization of the results for geometries of practical importance. So far, the application tool can represent plates variable in their geometries and in positioning of the point of measurement. The option for other geometries are also possible e.g. a turbine blade.
Improvement to Stress Calculation Model of LRM in Thick Plate
Authors: Liao Kai , Li Li Jun , Wu Yun Xin , Gong Hai
Published: August 2014

Layer removal method is an experiment method which is used to calculate the average stress indirectly by deformation of the specimen. However, in the experiment, some certain predeformation can be caused after each clamping, which can affect the accuracy of the test data, and make the deformation data larger. Based on the comparison of the simulation calculation, this paper builds an amended function by fitting the deformation error, which solves the deviation caused by larger deformation on stress calculation while the specimen is milled by layer, that is to say, the stress calculation model can be compensated by this function. This method can make the experimental calculation model more accurate.
Stoney Formula: Investigation of Curvature Measurements by Optical Profilometer
Authors: Ardigo Maria Rosa , Ahmed Maher , Besnard Aurélien
Published: August 2014

Thin films’ residual stress is often determined by the Stoney formula, using the measurements of the substrate curvature, even if the required hypotheses are not completely respected. In this study, a 2.2 µm titanium nitride coating was deposited by reactive sputtering on a silicon substrate. The Stoney formula was used in order to calculate the residual stress of the film. The radius of curvature was measured, before and after coating by optical profilometer, considering the whole surface of the sample. The effect of the substrate shape (square and rectangular) with various dimensions was investigated. We showed that the shape of the substrate influence strongly the deformation. Moreover, it was highlighted that the choice of the radius (maximum value, minimum value, mean value, with or without initial curvature correction) is critical to the determination of the stress.
Characterisation of In-Depth Stress State by Magnetic Barkhausen Noise on Machined Steel Acquiring Different Frequency Bands
Authors: Lasaosa Aitor , Gurruchaga Kizkitza , García Navas Virginia , Martínez-de-Guereñu Ane
Published: August 2014

The use of magnetic Barkhausen noise (MBN) signal to non-destructively characterize the in-depth residual stress state of machined steel was investigated. The effect of the frequency of the magnetic field applied and of analysing the resulting MBN signal in different frequency bands for an in-depth residual stress characterisation is discussed. The effect of the residual stress on each of the parameters derived from the MBN signal is analysed comparing with the result of the XRD method.
Residual Stress Measurement of Shot-Peened Steel Rings by Barkhausen Noise, ESPI Hole-Drilling and X-Ray Diffraction
Authors: Rickert Theo J. , Thomas James J. , Suominen Lasse
Published: August 2014

Shot-Peening is used to generate surface-near compressive residual stresses in final shape parts, usually to improve their fatigue properties. The success of the process can be checked in different ways. XRD and Hole-Drilling determine quantitative stress depth profiles in specific locations. Barkhausen noise measurements evaluate a near-surface zone in real-time and can cover large areas quickly. It is a fully nondestructive method. This study compares ESPI Hole-Drilling, which is a very fast technique, and XRD, which is very precise but slower, to Barkhausen Noise results for the case of three steel rings shot-peened with different intensities.
Identification of Inhomogeneous Residual Stress State in Elastic Cylinder within the Framework of Plane Strain
Authors: Bogachev Ivan V. , Dudarev Vladimir Vladimirovich , Nedin Rostislav Dmitrievich , Vatulyan Alexander Ovanesovich
Published: August 2014

The problem on radial oscillations of an elastic cylinder with inhomogeneous residual stress (RS) is considered. Two acoustic techniques of RS reconstructing are suggested. Within the framework of the first method, a set of radial displacement values is assumed to be known, while the frequency is fixed. Within the framework of the second method, the radial displacement value at the outer radius is assumed to be known for a set of frequencies. The examples of numerical identification experiments are presented.
Influence of Beam Speed on Residual Stresses in the Vicinity of Laser Welds
Authors: Ganev Nikolaj , Kolařík Kamil , Pala Zdenek , Němeček Stanislav , Čapek Jiří
Published: August 2014

One of the drawbacks of the laser welding is distortion of the welded bodies that is closely linked with the generation and redistribution of residual stresses in the vicinity of the weld. In this contribution, mapping of surface macroscopic residual stresses and grain sizes was performed for several welds created with the laser beam with various speeds. Larger distortions are exhibited by samples manufactured with higher laser beam speed, which also exhibit substantial compressive residual stresses perpendicularly to the welds axis.
Residual Stresses of Explosion Cladded Composite Plates of ZERON 100 Superduplex Stainless Steel and ASTM SA516-70 Carbon Steel
Authors: Varavallo Rogério , de Melo Moreira Vitor , Paes Vinicius , Brito Pedro , Olivas Jose , Pinto Haroldo Cavalcanti
Published: August 2014

In the present work bimetal composite plates of ZERON 100 superduplex stainless steel and ASME SA516-70 carbon steel were produced by explosion welding and submitted to post weld heat treatment for stress relief. The cross section microstructure of the cladded plates was characterized by optical microscopy and scanning electron microscopy and the hardness profile across the weld interface was determined. Residual stress analysis by X-ray diffraction was performed before and after heat treatment on the stainless steel side of the cladded plates. In the as-welded condition, metallography analysis indicated severe plastic deformation at the welded interface and a wavy morphology characteristic of high adhesive strength. Elevated tensile residual stresses were created as a result of the welding process. The heat treatment process applied (6h at 250°C) did not alter hardness at the welded interface nor the residual stress state in the cladded materials.
Influence of Welding Defects on Residual Stresses: Numerical Study
Authors: Frih Intissar , Adragna Pierre Antoine , Montay Guillaume
Published: August 2014

This paper presents a study on the application of the finite element methods to predict the influence of a defect on the residual stress distribution in a T-welded structure. A defect is introduced in a numerical model firstly without residual stress to see its impact (size and position) on the stress distribution. Secondly the most critical defect (determined previously) is simulated with a residual stress gradient. The obtained results are useful for computation stress concentration factor due to weld residual stresses.
A Profile-Based Method of Determining Intragranular Strains Using Kossel Diffraction Patterns
Authors: Morawiec Adam
Published: August 2014

Kossel microdiffraction is one of a few experimental methods of investigating heterogeneities of elastic stresses within crystallites. With digitally recorded back-reflection Kossel patterns, one can determine absolute lattice parameters, and hence lattice strains and stresses, based on geometry of Kossel lines, but the strain resolution of this approach is limited by finite widths of the lines. A new method is proposed which considerably improves the resolution in cases when the patterns originate from areas with similar lattice orientations. The method is based on determination of differences between pattern geometries: lattice strains are calculated from mutual shifts of intensity profiles of Kossel lines. The strain accuracy of this profile-based approach was estimated. It is demonstrated that the limit of strain resolution reaches a few parts per hundred thousand, i.e., it is nearly one order of magnitude better than that of the conventional Kossel-based lattice parameter refinement. This improvement concerns the critical range of lattice strain, and it constitutes a qualitative leap in resolution. The paper describes main aspects of the new approach and strain resolution tests.
Estimation of Cross-Sectional Residual Stress Distributionon Hardened Layer of Carburized Chromium-Molybdenum Steel by Electron Backscattering Diffraction Method
Authors: Sakaida Yoshihisa , Inayama Tomohito , Yashiro Shigeki
Published: August 2014

A chromiummolybdenum steel composed of 0.20 mass% carbon was used as a starting material. Three kinds of specimens having different case depths were made by carburizing and quenching. Using the scanning electron microscope, the crystallographic information was measured on the cross-sectional hardened layer by EBSD (electron backscattering diffraction) technique. The KAM (kernel average misorientation, Θ) maps were calculated from the carburized surface to the interior below the case depth of each specimen. The area-average, Θmean, of the KAM map was compared to the case depth and the cross-sectional residual stress distribution measured by x-ray. As a result, the area-average of the hardened layer was larger than that of the interior of specimen after quenching. The estimated depth of the increment in the Θmean was found to accord to the case depth and be proportional to the depth in which large compressive residual stress was distributed on the gradually polished surface. Therefore, both the case depth and eigen strain distribution that induce the compressive residual stress are indirectly estimable by electron backscattering diffraction method.
Microstructure and Residual Stresses of Laser Structured Surfaces
Authors: Preußner Johannes , Oeser Sabine , Pfeiffer Wulf , Temmler André , Willenborg Edgar
Published: August 2014

A new approach to structure metallic surfaces with laser radiation is structuring by remelting. In this process no material is removed but reallocated by melting. The laser power was adapted linearly to the increasing laser beam diameter for laser remelted (polished) samples. A carbon depleted area could be found close to the remelted zone accompanied with a local minimum in hardness. The surface residual stresses tend from tensile to compressive with increasing laser beam diameter/laser power and number of repetitions for laser structured and laser remelted samples. The residual stresses are a result of combined shrinkage (tensile) and transformation (compressive) stresses.
Measurement of Pre-Self-Balanced Surface Residual Stresses Induced by Milling in Titanium Alloys and the FEM Validation
Authors: Meng Long Hui , He Ning , Li Liang , Yang Yin Fei , Zhao Wei
Published: August 2014

Flank milling was used to machine titanium alloy workpieces, and there would be high residual stresses induced by milling in the superficial layer of the workpieces. Corrode the stress layers gradually and measure the changes of workpiece’s bending deflection during the corrosion process. With reverse thinking, calculate the stress values in the upper layers based on the values in the bottom layers and the changes of the bending deflection. At last, the stress values got by this method are prior to the self-balanced state, so the result rules out the factors of the workpiece’ size and shape. The deformations of workpieces with different sizes and shapes can be predicted accurately based on the stress values got by this method. The correctness of the method has been verified by Finite Element Method(FEM).
Modelling Machining-Induced Residual Stresses after Laser-Assisted Turning of Steels
Authors: Nasr Mohamed N.A. , Balbaa Mohamed , Elgamal Hassan
Published: August 2014

The current study examines the effects of laser assistance on machining-induced residual stresses (RS), using finite element modelling, during turning of steels. Dry orthogonal cutting was modelled, along with the pre-heating effect of the laser beam. AISI 4340 steel was used in the current work. Laser-assisted machining (LAM) resulted in higher surface tensile RS compared to conventional machining, with more pronounced effects at lower feed rates. This is basically because the assisted material experienced higher plastic deformation, due to thermal softening, as well as higher temperatures, which are both attributed to the pre-heating effect of LAM.
Predicting the Effects of Grain Size on Machining-Induced Residual Stresses in Steels
Authors: Nasr Mohamed N.A.
Published: August 2014

The current study examines the effect of grain size on machining-induced residual stresses (RS), during turning, using finite element modelling. Based on the well-known inverse relation between grain size and material strength, the grain size effect was simulated via changing the workpiece yield strength. This was also done at different strain hardening rates. The model was validated using four materials. Larger grain size (lower yield strength) resulted in higher surface tensile RS. This is attributed to the surface layer being subjected to higher compressive plastic deformation, as well as higher workpiece temperatures, which both contribute to higher tensile RS.
Effect of Different Manufacturing Process Steps on the Final Residual Stress Depth Profile along the Process Chain of Autofrettaged Thick-Walled-Cylinders
Authors: Brünnet Horst , Hofmann Michael , Lyubenova Nataliya , Bähre Dirk
Published: August 2014

Selectively induced compressive residual stress depth profiles are gaining increasing importance as design tool for internally pressurized components. Hydraulic Autofrettage (AF) is a well-known manufacturing process to induce pronounced compressive residual stresses. However, AF does not stand alone in the technical process chain. In this paper, results from neutron diffraction experiments performed on thick-walled cylinders are presented and compared to finite-element simulations with Abaqus/CAE. The impact on the final residual stress depth profile after pre-machining, Autofrettage and post-machining is discussed.
Effect of Thermal Residual Stresses on Bonded Structures Containing Cold Expanded and Bolted Holes
Authors: Syed Abdul Khadar , Fitzpatrick Michael E. , Moffatt James E.
Published: August 2014

The primary focus of this investigation is to determine the distribution of thermal residual stresses that result during composite bonding processes, and the effect on stresses generated during the subsequent cold expansion of holes. Residual stress measurements were carried out using neutron diffraction techniques. Results show that the cold expansion process resulted in radial compressive stresses 3-4 mm from the edge of the hole and there was no significant effect of thermal residual stresses from the bonding process on the cold expansion and bolted stresses.
Effect of Ultrasonic Impact Treatment (UIT) on Fatigue Strength of Welded Joints
Authors: Suzuki Tamaki , Okawa Teppei , Shimanuki Hiroshi , Nose Tetsuro , Ohta Noriaki , Suzuki Hiroshi , Moriai Atsushi
Published: August 2014

Ultrasonic impact treatment (UIT) is a remarkable post-weld treatment, which reduce not only in external stress concentration, but also in residual stress in a welded joints. Internal and surface stresses were investigated on UIT treated welded joints by neutron and X-ray diffraction method. This paper discuses the effect of internal and surface residual stress and surface stress concentration after UIT on fatigue resistance by the comparison of fatigue experiments to predictions calculated with the results of the experimental investigations.