bluuebunny/crossref_metadata_2025_split huggingface dataset:
Artificial Neural Network (ANN) Approach to Hardness Prediction of Aged Aluminium 2024 and 6063 Alloys
Authors: Meyveci Ahmet , Karacan İsmail , Durmuş Hülya , Çalıgülü Uğur 
Published: December 2013

Abstract
In this study, the effect of aging heat treatment on the hardness of AA 2024 and AA 6063 aluminum alloys was investigated by experimental and an Artificial Neural Network (ANN). AA 2024 and AA 6063 aluminum alloys were solution treated at two different temperatures of 490° C and 520° C. Then both samples were cooled to room temperature. After this process, the samples were aged at three different temperatures (140° C, 180° C, 220° C) for ten different periods of time (2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 h.). The experimental results were trained in an ANNs program, and the results were compared with experimental values. It is observed that the experimental results coincided with the ANNs results.
Cavitation Erosion Behaviour of Stainless Steels with Constant Nickel and Variable Chromium Content
Authors: Bordeasu Ilare , Mitelea Ion 
Published: December 2013

Abstract
The paper highlights new aspects in the evaluation of cavitation erosion resistance based on the chromium content variation and implicit on the Cr/Ni equivalent which constitutes the microstructure development using the information given by the Schaeffler diagram. The presented and analysed results show that it is possible to establish an optimum relation between the chromium and nickel content, in order to obtain a substantial increase of the cavitation erosion resistance. For this purpose, four stainless steels used in manufacturing of machinery parts, heavily subject to cavitation such as hydraulic turbine runners and pump impellers, were analyzed from the point of view of cavitation erosion. The cavitation erosion behaviour was evaluated by the microstructure behaviour investigated through optic and electronic microscopy and by comparisons with the characteristic curves for reference steels.
Weldability Characteristics of Dissimilar Al/Cu Friction Stir Weld Joints
Authors: Sarsilmaz Furkan 
Published: December 2013

Abstract
In the present investigation, the AA1030 aluminium alloy and commercially pure copper plates were joined by friction stir welding. The effect of the processing parameters on the interface morphology, microstructure and strength of the joints was analyzed. The experimental results showed that some intermetallic compounds such as AlCu, Al4Cu9 and Al2Cu cause the weld to crack during the friction stir welding process on the centerline of the weld. Especially at lower traverse speeds such as 60, 90, and 125 mm/min, some tunnels and voids were detected in the Aluminium close to the Al/Cu interface. The maximum tensile strength of the samples was obtained at a traverse speed of 160 mm/min getting by without cavity defects in the weld. In addition, the fracture morphology revealed both partially brittle and cleavage-like fracture.
Correlation Between Work Index and Mechanical Properties of some Saudi Ores
Authors: Haffez Gamal S. Abdel 
Published: December 2013

Abstract
The crushing energy for applications in the mineral processing industry is usually determined by an empirical bond index, regardless of the mechanical properties of a rock. Although several attempts have been made to obtain the comminution energy based on theoretical approaches, it would be beneficial to examine this relation based on a physical concept. In this paper, some Saudi samples of bauxite, kaolinite, granodiorite, magnetite, granite, feldspar and quartz were tested for hardness, abrasion, compressive strength as well as modulus of elasticity and the bond work index of these samples was estimated. The value of the bond work index of the above samples has shown a variation from 10.8 kWh ton-1 for bauxite (high abrasion value and low compressive strength) to 20.4 kWh ton-1 for granite (low abrasion value and high modulus of elasticity). The correlation between the abrasion value (X2) and work index (Wi) is found to be Wi = −1.8 Ln(X2) + 11.5 with a correlation coefficient of 0.80.
TMF Cracking in Metallic Heat Shields of Gas Turbine Combustion Chambers
Authors: Neidel Andreas , Cagliyan Erhan , Jahnke Anne , Riesenbeck Susanne , Ullrich Thomas , Wallich Sebastian 
Published: December 2013

Abstract
Several metallic heat shields of the combustion chamber of a large industrial gas turbine were affected by thermo-mechanical cracking after long service exposure. The base metal Alloy 617 is coated with a thermal barrier system. While microstructural evidence allowed the exclusion of creep damage as the metallurgical cause of failure, other microstructural features led to the conclusion that the affected components were massively overheated and experienced service temperatures of up to 1100 °C. There are several possible reasons for such overheating, ranging from burner failure and lack of cooling to abuse in service. A discussion of these factors is not the subject of this case study.
Ein neues Verfahren zur präzisen Analyse des diffusiblen Wasserstoffanteils in Stählen
Authors: Kühn Sebastian , Luithle Alexander , Unterumsberger Fabian , Pohl Michael 
Published: December 2013

Kurzfassung
Hochfeste Stähle mit einer kubisch raumzentrierten Gitterstruktur können bereits bei sehr geringen Wasserstoffgehalten zur verzögerten Rissbildung neigen. Zum sicheren Einsatz dieser Stähle ist deshalb die Kenntnis des enthaltenen diffusiblen Wasserstoffes notwendig, der sich schadensursächlich auswirken kann. In diesem Beitrag wird die Funk­tionsweise eines neuen Wasserstoffanalyseverfahrens beschrieben, welches sich in der Verfahrensabfolge von konventionellen Verfahren, wie der Trägergasheißextraktion bzw. Trägergasschmelzextraktion, unterscheidet. Bei dem entwickelten Verfahren, der sogenannten Hydrogen Collecting Analysis (HCA), werden die zu analysierenden Proben in Glasküvetten eingeschmolzen und die Wasserstoffextraktion aus der Probe und die Wasserstoffanalytik in zwei konsekutive Verfahrensschritte unterteilt. Mit dem HCA-Verfahren können die Anteile an diffusiblem Wasserstoff in Metallproben im Hundertstel-ppm-Bereich hochgenau analysiert werden.
Effect of Pin Penetration Depth on the Mechanical Properties of Friction Stir Spot Welded Aluminum and Copper
Authors: Özdemir Uğur , Sayer Sami , Yeni Çınar 
Published: December 2013

Abstract
The effect of pin penetration depth on the mechanical properties of friction stir spot welded (FSSW) aluminum alloy 1050 and pure copper has been investigated. For a certian tool geometry, constant tool rotation speed and penetration time, the materials have been friction stir spot welded in three different penetration depths, namely 2.8 mm, 4 mm and 5 mm. Tensile shear tests, microhardness measurements and micostructural investigation have been carried out on the welded specimens in order to investigate the effect of penetration depth. 2.8 mm plunge depth has resulted in a weak joint, whereas 4 mm and 5 mm plunge depths offer acceptable tensile shear results. Presence of intermetallic phases had an influence on the tensile shear and hardness values.
Fatigue Life Behaviour of Nanocomposite Coated Carbon Steel
Authors: Hedia Hassan S. , Aldousari S. M. , Khairy A. , Aljabarti Ezat 
Published: December 2013

Abstract
Recently, nano-materials have received increasingly more attention for their potential applications as structural and functional materials. The unique mechanical properties of CNTs, their high strength and stiffness and the enormous aspect ratio provide potentials for the improvement of the mechanical properties of structural materials. The aim of this research is to investigate experimentally the effect of nanocom­posite coating on the fatigue life of carbon steel AISI 1045 specimens with different surface finishes. Nanoadhesives of epoxy resin are synthesized and evaluated. They are originally modified by multiwalled carbon nanotubes (MWCNT) with 0.5 wt.-% as reinforcement. Fatigue tests are conducted on the respective specimens by a rotating bending machine of the cantilever type. Comparing the results for specimens coated with 0.5 wt.-% MWCNT-epoxy composition with the base materials it is found that fatigue life increased five times for a roughness of 0.3 µm and three times for an average specimen roughness of 0.8, 1.6 and 2.5 µm, respectively.
Surface Roughness Changes and Corrosion on Nickel Titanium Orthodontic Wires Compared to Stainless Steel Wires in Various Artificial Salivas
Authors: Kucukyildirim Bedri Onur , Eker Aysegul Akdogan 
Published: December 2013

Abstract
Nickel titanium shape memory alloy and stainless steel orthodontic wires were exposed to three different artificial saliva solutions which are modified Fusayama, modified Fusayama with 1g/l NaF addition and modified Fusayama with 1.7 % H3PO4 addition. Under conditions similar to oral cavity temperature, corrosion behaviours were observed by using weight loss method and by macro surface photographic observations. Also, surface roughness of wires were investigated and compared. Consequently, it was determined that corrosion rates of all NiTi wires exposed to the modified Fusayama solutions with NaF addition are higher because of galvanic interaction of NiTi and hydrogen embrittlement of titanium. Also, surface roughness of NiTi wires were increased in modified Fusayama solution with NaF addition.
Experimental and Numerical Strategies to Consider Hole Eccentricity for Residual Stress Measurement with the Hole Drilling Method
Authors: Nau Andreas , Scholtes Berthold 
Published: December 2013

Abstract
For the analysis of residual stress depth distributions the semi-destructive incremental hole drilling method is the process of choice for quick and cost-efficient measurements. Nevertheless, the experimental execution has to be carried out carefully. Minor deviations of the ideal case, for example incorrect depth setting or eccentricity of the drilled hole to the center of the applied strain gage rosette can result in large errors or invalid results. In this paper two different strategies are presented, in order to take eccentricity into consideration. The first strategy requires a specific strain gage rosette consisting of eight single strain gages arranged at 45° angle to each other. The second strategy works with standard strain gage rosettes, but with calibration functions modified for the eccentric case. Both strategies are able to reveal and to correct the consequences of eccentricity on the results of stress analyses. In order to improve the quantitative accuracy of residual stress measurements the latter strategy should be preferred.
Rolling Contact Fatigue of Wheel and Rail
Authors: Dörner Florian , Kleiner Otto , Schindler Christian , Starke Peter , Eifler Dietmar 
Published: December 2013

Abstract
This investigation describes rolling contact fatigue phenomena in the wheel/rail-contact area of railway vehicles. In the scope of this paper new calculation, experimental results of stresses and strains within the wheel as well as a new method the determination of fatigue strength are presented. The stress fields in railway wheels introduced by different loads are calculated using the finite element method. The results are validated on a full-scale test rig. The results of the measurements are used to draw conclusions for the fatigue strength of wheels. Furthermore, the fast and cost saving “PHYBALLIT” method for the determination of fatigue properties is described.
Detection of Defects in Natural Composite Materials Using Thermal Imaging Technique
Authors: Suriani M. J. , Ali Aidy , Khalina A. , Sapuan S. M. , Abdullah S. , Haftirman  
Published: December 2013

Abstract
Nowadays, non-destructive testing (NDT) is frequently replacing destructive techniques in determining the properties of materials. In this study, defects in Kenaf/epoxy composite materials were detected using an inyyfrared (IR) thermal imaging technique, which is one of the most practical non-destructive techniques currently applied. Kenaf bast fibres were used to fabricate composite materials with epoxy resin as a binding material. The composites were manufactured using a manual lay-up process. The thermography analysis of the IR camera were verified by optical microscope and scanning electron microscope (SEM) investigations. The defect detection accuracy of this technology is 95%.
Effect of Curing Conditions on the Interface Strength of Single-Fibre Composite Specimens
Authors: Solmaz Murat Yavuz , Kaman Mete Onur , Turan Kadir 
Published: December 2013

Abstract
The purpose of this paper is to examine the effect of curing conditions on interface strength in single-fibre composites. Test specimens produced by using polyester resin and single glass fibre were cured under four different temperatures, which were room temperature, 40°C, 55°C and 70°C for three different curing periods, which were 1 hour, 4 hours and 8 hours. Afterwards they were subjected to tensile test. As a result of the examination under optic microscope, it has been observed that the major damage formations are in the form of matrix cracks and fibre fragments. Young modulus and therefore mechanical properties of single-fibre composite specimens improved after a treatment above 40°C.
Zur Lebensdauerberechnung faserverstärkter Kunststoffe im Automobilbau*
Authors: Oppermann Helge 
Published: December 2013

Kurzfassung
Faserverstärkte Kunststoffe finden im Automobilbau zunehmend auch für hochbelastete Bauteile Verwendung. Für die betriebsfeste Auslegung solcher Bauteile müssen zuverlässige Lebensdauerberechnungsverfahren zur Verfügung stehen. Die Methodenentwicklung zur Lebensdauerberechnung von faserverstärkten Kunststoffbauteilen und zu deren Verbindungstechniken steht im Automobilbau noch in den Anfängen. Zwar existieren bereits methodische Ansätze für Teilaspekte der Lebensdauerberechnung, jedoch ist die virtuelle betriebsfeste Auslegung von faserverstärkten Kunststoffbauteilen im Entwicklungsprozess heute noch nicht ohne experimentellen Mehraufwand möglich. Der experimentelle Prüfaufwand ist vergleichsweise zu Metallen bei den Composites aufgrund der Komplexität der Einflussfaktoren (Interlaminare Spannungen, Viskoelastizität, Alterung usw.) je nach Problemstellung deutlich größer. Dieser Aspekt ist auch bei der Methodenentwicklung zur Lebensdauerberechnung unbedingt zu berücksichtigen, d. h., der experimentelleAufwand zur Ermittlung der Materialdaten für die Berechnung darf ein akzeptables Maß nicht überschreiten.
Scanning-Laservibrometrie zur integrierten Bauteilüberwachung mit Hilfe von Ultraschallober­flächenwellen
Authors: Neumann Mirko Nikolaj , Schell Jochen , Lammering Rolf , Behrendt Reinhard 
Published: December 2013

Kurzfassung
Ultraschall-Lamb-Wellen werden aktuell als vielversprechende Möglichkeit zur Schadensdetektion in dünnwandigen Strukturen untersucht. Um die physikalischen Phänomene technisch gut ausnutzen zu können, ist das Ausbreitungsverhalten der Wellen und ihre Interaktion mit Defekten zu untersuchen. Gut geeignet hierfür sind optische Messtechniken, die sich durch Rückwirkungsfreiheit auf die mechanischen Strukturen auszeichnen – zum Beispiel die Laservibrometrie. Die Technik liefert im Scanning-Verfahren flächige, zeitkontinuierliche Schwingungsdaten zur Beurteilung der Wellenfelder. Im 3D-Scanning-Verfahren sind hierbei In-Plane- und Out-of-Plane-Schwingungen voneinander unterscheidbar, während sich die Verschiebungsinformationen bei der 1D-Vibrometrie bezüglich der Ortsrichtung vermischen, was zu Fehlinterpretationen führen kann. Lamb-Wellen in isotropen Platten und Faserverbundplatten werden kurz beschrieben und ihre Beobachtung mittels (3D-)Scanning-Vibrometrie vorgestellt. Ein kurzes Experiment mit transient angeregten Lamb-Wellen zur Detektion von Impact-Schäden in einer CFK-Platte wird vibrometrisch beobachtet und beschrieben, wobei eine gute Eignung von Lamb-Wellen zur Struktur­überwachung festgestellt wird.
Impact of High Pressure Hydrogen Atmosphere on the Mechanical Properties of Haynes 282 Superalloy
Authors: Bruchhausen Matthias , Fischer Burkhard , Hähner Peter , Soller Sebastian 
Published: December 2013

Abstract
Haynes 282 alloy is a newly developed nickel-base superalloy, with properties focussed on high creep strength, thermal stability, good weldability and fabricability, which might qualify it as a substitute for established materials like Hastelloy-X or René-41 e.g. in aerospace applications. However, so far no information on the sensitivity for hydrogen environment embrittlement (HEE) has been published for this material. In the present work, tensile tests under hydrogen atmosphere have been carried out at room temperature and the results have been compared to those from tests under argon. Haynes 282 is found to show significant hydrogen embrittlement.
Microstructure and Mechanical Behaviour of Friction Welded AISI 2205/AISI 1040 Steel Joints
Authors: Kirik İhsan , Özdemir Niyazi , Sarsilmaz Furkan 
Published: December 2013

Abstract
The goal of this study is to investigate the effect of friction time on mechanical and microstructural properties of dissimilar AISI 1040/AISI 2205 stainless steel couples. The experiments were carried out with continuous drive friction welding set-up. Friction welding experiments with different frictional times and constant friction pressure as well as rotational speed were carried out. The strength of the welds was determined by tensile strength tests. Hardness variation of the joint was also obtained. The results were compared with those of previous studies. The results of applied tests and observations showed that the properties of microstructure change and that the interface temperature increases with friction time. The best tensile strength of the joint was observed for the specimen welded at 1700 rpm rotation speed and a friction time of 3 s.
Zur Wiederverwendung von Durchläufern im Treppenstufenversuch
Authors: Müller Christian , Hinkelmann Karsten , Wächter Michael , Masendorf Rainer , Esderts Alfons 
Published: December 2013

Kurzfassung
Viele Bauteile sind während ihrer Nutzungsdauer schwingenden Beanspruchungen ausgesetzt. Ermüdungsfestigkeitsnachweise sollen den sicheren Betrieb schwingend beanspruchter Bauteile garantieren. Ein wichtiger Kennwert zur Führung von Ermüdungsfestigkeitsnachweisen ist die Bauteildauerfestigkeit. Ihre experimentelle Bestimmung ist zeit- und kostenintensiv. Häufig stehen nur wenige Prüfkörper zur Verfügung, sodass eine statistische Auswertung unmöglich wird. Um dennoch Aussagen über die Bauteildauerfestigkeit abzuleiten, können so genannte Durchläufer wiederholt eingesetzt werden. Im vorliegenden Beitrag werden die Auswirkungen des Wiedereinsatzes von Durchläufern diskutiert. Hierbei werden keine werkstoffmechanischen Betrachtungen zur Vorschädigung oder zur Trainierwirkung angestellt. Vielmehr werden Simulationsmethoden vorgestellt, mit denen sich maximale Fehler bei der 50%-Dauerfestigkeitsschätzung ableiten lassen. Durch nachträgliche Berücksichtigung des maximalen Fehlers kann ein Bemessungskennwert auch mit wenigen Proben abgeleitet werden.
Approximation of Damage Accumulation in Fibre Reinforced Polymers
Authors: Zachariev Georgi 
Published: December 2013

Abstract
A unified approach for the derivation of the known equations describing damage accumulation as a result of loading of fibre-reinforced polymers is proposed. The investigated materials are short glass fibre-reinforced polyoxymethylene (GF/POM) and long glass fibre-reinforced epoxyresin (GFRP). The damage structures themselves consist of the accumulation of additional internal surfaces within the entire material volume as measured by small angle scattering X-ray refractometry. On the basis of the concept for a loading percentage under creep, damage accumulations applying short-term and long-term loading are compared. It is shown that for the investigated materials our approximations by a double exponent function are more effective than the approximations according to Weibull. It is also shown how the coefficients of the double exponent cumulative function can be found.
Wear Behaviour of Heat Treated Hot Work Tool Steels under Dry Sliding Conditions
Authors: Polat Şeyda , Atapek Ş. Hakan , Türedi Enbiya , Aktaş Gülşah 
Published: December 2013

Abstract
In this study, commercial hot work tool steels were selected and their wear behaviour under dry sliding condition was investigated after heat treatment applications. In the first stage of the study, solution annealing, quenching, and finally tempering treatments were applied to the experimental steels. All samples were examined by light microscopy after metallographic preparations. In the second stage, hardness values (HRC) of the steels were determined to evaluate the surface resistance to wear. Finally, wear tests were carried out using ‘ball-on-disc’ type tribometer under dry sliding condition and all worn surfaces were characterized using both light and scanning electron microscopy. It is concluded that (i) the steels had typical tempered martensite matrices, (ii) alloy content affected the final microstructure and a finer matrix was obtained due to vanadium addition, (iii) hardness levels directly affected the coefficient of wear of steels, and (iv) worn surfaces exhibited abrasive and adhesive wear tracks.
Predictive Modelling of Ball Burnishing Process Using Regression Analysis and Neural Network
Authors: Ugur Esme , Kulekci Mustafa Kemal , Ozgun Sueda , Kazancoglu Yigit 
Published: December 2013

Abstract
The present paper focuses on two techniques, namely regression and neural network techniques, for predicting surface roughness in ball burnishing process. Values of surface roughness predicted by the two techniques were compared with experimental values. Also, the effects of the main burnishing parameters on surface roughness have been determined. Surface roughness (Ra) was taken as response (output) variable and burnishing force, number of passes, feed rate, and burnishing speed were taken as input parameters. Relationship between the surface roughness and burnishing parameters was found out for direct measurement of the surface roughness. Results showed the application of the regression and neural network models to accurately predict the surface roughness.
Einsatz der Bayes'schen Statistik in der Zuverlässigkeitsbestimmung von zerstörungsfreien Prüfsystemen
Authors: Kanzler Daniel , Müller Christina , Ewert Uwe , Pitkänen Jorma 
Published: December 2013

Abstract
Die Fehlerauffindwahrscheinlichkeit oder “Probability of Detection” ist zu einer wichtigen Qualitätskennzahl von zerstörungsfreien Prüfsystemen geworden. Die Einschätzung von nur künstlichen Fehlern ist jedoch als Bewertungsgrundlage meist nicht ausreichend. Die später verwendeten Prüfobjekte mit den real vorkommenden Fehlern sind die zu betrachtende Basis, für die der Endanwender eine gültige Qualitätseinschätzung der angewandten zerstörungsfreien Prüfung fordert. Jedoch ist bei dem Fall, dass die Datenmenge gering ist, auch die Aussage der POD beschränkt. Es muss daher eine Zwischenlösung gefunden werden, in der die Informationen von beiden Prüfungen kombiniert werden. Die Mathematik ermöglicht mit der Bayes'schen Statistik, diese Informationen miteinander zu kombinieren und somit beide Informationen in die Bewertung einfließen zu lassen. Dabei spielt jedoch der Zusammenhang zwischen Signal und Fehlerausprägung eine wichtige Rolle. Praktisch angewendet und erprobt wird diese Vorgehensweise für die Bewertung der zerstörungsfreien Prüfungen der Firma POSIVA, die sich mit dem Bau eines Endlagers für hochradioaktiven Abfall in Finnland beschäftigt.