The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform
Hamid Jahed - One of the best experts on this subject based on the ideXlab platform.
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an asymmetric elastic plastic analysis of the load controlled Rotating Bending Test and its application in the fatigue life estimation of wrought magnesium az31b
International Journal of Fatigue, 2014Co-Authors: E Kalatehmollaei, Hassan Mahmoudiasl, Hamid JahedAbstract:The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.ijfatigue.2014.02.012 © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
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An asymmetric elastic–plastic analysis of the load-controlled Rotating Bending Test and its application in the fatigue life estimation of wrought magnesium AZ31B
International Journal of Fatigue, 2014Co-Authors: E Kalatehmollaei, Hassan Mahmoudi-asl, Hamid JahedAbstract:The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.ijfatigue.2014.02.012 © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
E Kalatehmollaei - One of the best experts on this subject based on the ideXlab platform.
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an asymmetric elastic plastic analysis of the load controlled Rotating Bending Test and its application in the fatigue life estimation of wrought magnesium az31b
International Journal of Fatigue, 2014Co-Authors: E Kalatehmollaei, Hassan Mahmoudiasl, Hamid JahedAbstract:The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.ijfatigue.2014.02.012 © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
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An asymmetric elastic–plastic analysis of the load-controlled Rotating Bending Test and its application in the fatigue life estimation of wrought magnesium AZ31B
International Journal of Fatigue, 2014Co-Authors: E Kalatehmollaei, Hassan Mahmoudi-asl, Hamid JahedAbstract:The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.ijfatigue.2014.02.012 © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Gianni Nicoletto - One of the best experts on this subject based on the ideXlab platform.
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XVII International Colloquium on Mechanical Fatigue of Metals (ICMFM17) High Temperature Fatigue Behavior of Eutectic Al-Si-Alloys used for Piston Production
2020Co-Authors: Gianni Nicoletto, E. Riva, A. Di FilippoAbstract:Pistons of IC engines are typically subjected during operation to high cycle fatigue loading cycles at high temperatures (up to 350°C) in areas facing the combustion chamber. During operation the high temperature exposure results in a progressive loss of fatigue strength of the material at the weakest areas of the piston and may eventually results in a premature failure by crack initiation and propagation. The quantification of the temperature effect on fatigue strength inevitably require experimentation since such data are scarce. An extensive fatigue Testing program of eutectic Al-Si alloys at room temperature and at several high temperatures (250 °C, 300°C and 350°C) is reported. Specimens were extracted from piston crowns and Tested in a Rotating Bending Test machine. The resulting fatigue strength loss at 10 7 cycles is quantified by a staircase approach. The influence of the Test temperature is investigated in terms of chemical composition, process route and of mechanisms of fracture observed in the broken specimens.
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A novel Test method for the fatigue characterization of metal powder bed fused alloys
Procedia structural integrity, 2017Co-Authors: Gianni NicolettoAbstract:Abstract This research addresses the conflicting factors of high costs of fatigue Testing and large number of influencing factors that need to be investigated for PBF material and process qualification. Metal powders are remarkably expensive, the PBF production process requires expensive systems and fatigue Testing requires multiple specimens (depending the required degree of confidence) to characterize a single material/process combination. In this paper a novel fatigue Test method aimed at the peculiar needs of PBF technology is initially presented and fatigue data obtained on Direct Metal Laser Sintering Ti6Al4V are validated against standard Rotating Bending Test results. Then, the link between microstructure and directional fatigue behavior is demonstrated using the present methodology and SLM Inconel 718: namely, the stress direction parallel to build direction is the most severe. Finally, the new Test method is applied to the investigation of the fatigue notch sensitivity of DMLS Ti6Al4V in relation to the notch fabrication process. Round notches in specimens with opposite fabrication orientations (i.e. up-skin vs down-skin) resulted in two notch fatigue factors and the up-skin notch has a better fatigue strength than the down-skin notch.
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The role of elevated temperature exposure on structural evolution and fatigue strength of eutectic AlSi12 alloys
International Journal of Fatigue, 2016Co-Authors: Radomila Konečná, Gianni Nicoletto, Ludvík Kunz, E. RivaAbstract:Abstract Pistons of internal combustion (IC) engines are typically subjected during operation to high cycle fatigue loading at elevated temperatures (up to 350 °C). The materials typically used for piston production are eutectic Al–Si alloys for their excellent fluidity and suitable mechanical properties. Results of a fatigue Testing program of eutectic Al–Si alloys at room temperature and at elevated temperatures (250 °C, 300 °C and 350 °C) performed with the aim to support piston design and material optimization are reported in this paper. Specimens were extracted from piston crowns and Tested in a Rotating Bending Test machine. The fatigue strength at 10 7 cycles was quantified by a staircase approach. To investigate the strengthening mechanism based on the formation of precipitates (Guinier–Preston (GP) zones) during decomposition of a metastable supersaturated solid solution, a structural investigation of one of the alloys before and after fatigue Testing at elevated temperatures was conducted. Metallography, color etching, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to elucidate the following aspects: (1) the structural features of the alloy (dendrites of α-phase, primary Si particle size and distribution, morphology and distribution of intermetallic phases); (2) the changes of the strengthening mechanism (GP zones) with elevated temperature exposure.
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High Temperature Fatigue Behavior of Eutectic Al-Si-Alloys Used for Piston Production
Procedia Engineering, 2014Co-Authors: Gianni Nicoletto, E. Riva, A. Di FilippoAbstract:Abstract Pistons of IC engines are typically subjected during operation to high cycle fatigue loading cycles at high temperatures (up to 350 °C) in areas facing the combustion chamber. During operation the high temperature exposure results in a progressive loss of fatigue strength of the material at the weakest areas of the piston and may eventually results in a premature failure by crack initiation and propagation. The quantification of the temperature effect on fatigue strength inevitably require experimentation since such data are scarce. An extensive fatigue Testing program of eutectic Al-Si alloys at room temperature and at several high temperatures (250 °C, 300 °C and 350 °C) is reported. Specimens were extracted from piston crowns and Tested in a Rotating Bending Test machine. The resulting fatigue strength loss at 107 cycles is quantified by a staircase approach. The influence of the Test temperature is investigated in terms of chemical composition, process route and of mechanisms of fracture observed in the broken specimens.
T. P. Kicher - One of the best experts on this subject based on the ideXlab platform.
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A study of the fatigue properties of small diameter wires used in intramuscular electrodes
Journal of Biomedical Materials Research, 1991Co-Authors: Avram Scheiner, J. Thomas Mortimer, T. P. KicherAbstract:Single and multi-strand stainless steel and cobalt-nickel alloy wires, with strand diameters from 26 to 46 microns, were fatigue Tested using a modified Rotating Bending Test to determine what factors are most important in controlling fatigue life. The relation between cyclic strain and cyclic life was determined for each material by cyclically straining Test specimens at various strain ranges and recording the number of cycles to failure. The results show that (a) the fatigue curves of the 316LVM, MP35N, DBS, and Syntacoben wires are very similar and have many of the same fatigue characteristics of specimens of large cross section. (b) Multi-stranded wires have the same average fatigue life as their individual constituent strands, but the variance of that life is smaller. (c) Deformities in the wire, which are created during the manufacturing, appear to have the effect of shortening the fatigue life of these small section wires. (d) Observation of wire fracture surfaces show a relatively small crack propagation zone and a large fast fracture zone suggesting that most of the fatigue life of these small wires is in the original crack formation, which creates a large stress concentration and quickly leads to wire failure. (e) The size of the wire cross sectional area is of secondary importance compared to the amplitude of the maximum cyclic strain of the individual strands in determining fatigue life of the cable. To maximize the fatigue life of electrodes in vivo, the highest fatigue life for a given Bending radius of curvature is desired. This suggests wire strands should be manufactured at the smallest diameter possible (without introducing structural flaws) to maximize service life.
Christof Sommitsch - One of the best experts on this subject based on the ideXlab platform.
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construction of a corrosion Test chamber for the installation in a Rotating Bending machine for corrosion fatigue Tests of cr mn n austenitic steels used in the oil field industry
BHM Berg- und Hüttenmännische Monatshefte, 2015Co-Authors: Dominik Leidinger, Bernd Holper, Christof SommitschAbstract:The high requirements of materials used in drilling and exploration in the earth’s crust (oil, gas, and geothermal wells) are reflected by both multi-axial stresses and corrosive attacks. Schoeller-Bleckmann Oilfield Equipment AG (SBO) is the world leader in the production of high precision parts for the oilfield industry. The priorities of the company are non-magnetic drill string components for directional drilling. Drill string components are subjected to severe mechanical and environmental loads. As a consequence, the high quality standards are proved by several lab Tests. Among other facilities, a Rotating Bending Test equipment is used to simulate the actual loads on the material. Current Rotating Bending Tests at SBO are done in ambient air and not at elevated temperatures or in corrosive atmosphere. The aim of this work was to construct a corrosion Test chamber to install it in the Rotating Bending machine and to simulate the environmental influences to the used material. The determined corrosion fatigue results for different environments are compared to those in ambient air. The Tests carried out showed that the fatigue properties of the material decrease in a corrosive environment.
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Construction of a Corrosion Test Chamber for the Installation in a Rotating Bending Machine for Corrosion Fatigue Tests of Cr-Mn-N Austenitic Steels Used in the Oil-field Industry
BHM Berg- und Hüttenmännische Monatshefte, 2015Co-Authors: Dominik Leidinger, Bernd Holper, Christof SommitschAbstract:The high requirements of materials used in drilling and exploration in the earth’s crust (oil, gas, and geothermal wells) are reflected by both multi-axial stresses and corrosive attacks. Schoeller-Bleckmann Oilfield Equipment AG (SBO) is the world leader in the production of high precision parts for the oilfield industry. The priorities of the company are non-magnetic drill string components for directional drilling. Drill string components are subjected to severe mechanical and environmental loads. As a consequence, the high quality standards are proved by several lab Tests. Among other facilities, a Rotating Bending Test equipment is used to simulate the actual loads on the material. Current Rotating Bending Tests at SBO are done in ambient air and not at elevated temperatures or in corrosive atmosphere. The aim of this work was to construct a corrosion Test chamber to install it in the Rotating Bending machine and to simulate the environmental influences to the used material. The determined corrosion fatigue results for different environments are compared to those in ambient air. The Tests carried out showed that the fatigue properties of the material decrease in a corrosive environment. Die Anforderungen an die Werkstoffe, die für Explorations- und Erschließungsbohrungen von Energiequellen in der Erdkruste (Erdöl und Erdgas) verwendet werden, sind sehr hoch aufgrund unter Rotation des Bohrstranges einwirkender Kräfte und Umgebungseinflüsse (korrosive Medien und Temperatur). Schoeller-Bleckmann Oilfield Equipment AG (SBO) ist Weltmarktführer bei der Herstellung von Hochpräzisionsteilen für die Ölfeld-Industrie. Die Schwerpunkte sind dabei amagnetische Bohrstrangkomponenten für die Richtbohrtechnologie. Da an die einzelnen Bohrstrangkomponenten sehr hohe mechanische Anforderungen gestellt werden und eine hohe Qualität gefordert wird, werden die dafür verwendeten Werkstoffe (Cr-Mn-N-Austenite) im Unternehmen unter anderem einer Umlaufbiegeprüfung, bei der die Rotation und die dabei auf den Bohrstrang einwirkende Biegespannung simuliert wird, unterzogen. Das Problem, das in dieser Arbeit behandelt wird, ist, dass die derzeitigen Umlaufbiegeprüfungen bei SBO an Umgebungsluft und nicht in temperatur- und korrosionsbeaufschlagter Umgebung geprüft werden. Dadurch ergibt sich auch die Aufgabenstellung und Forderung nach der Konstruktion einer Korrosionsprüfkammer zum Einbau in die Umlaufbiegemaschine, um die geforderten Umgebungseinflüsse auf die Werkstoffe simulieren zu können. Die dabei erreichten Werkstoffkennwerte unter Korrosion und definierten Temperaturen können nun mit jenen in Umgebungsluft verglichen werden und geben nun Aufschluss über das Verhalten des Materials in wirklichkeitsgetreuem Einsatz. Die durchgeführten Tests zeigten, dass unter den gegebenen Untersuchungsbedingungen in korrosiver Umgebung die Dauerfestigkeit des geprüften Materials abnimmt.
