The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Robert Liebich - One of the best experts on this subject based on the ideXlab platform.
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a time dependent equivalent stress function for proportional and non proportional transient loaded and Notched metallic Components
International Journal of Fatigue, 2017Co-Authors: Heinz Mertens, Robert LiebichAbstract:Abstract The novel “Modified Mohr Mises” (MMM) Hypothesis allows the assessment of non-proportional stresses within a fully automated process, due to its invariant equivalent stress notation. Those non-proportional stresses are most common in complex structures of aircrafts, spacecrafts and vehicles for instance. The new MMM Hypothesis provides a physically reasonable sign determination derived directly from the effective stress Components. Supporting effects through material and adjacent material areas and local geometries are considered in the theory as well. The use of a suitable tension shear strength ratio allows a consideration of anisotropic material behavior in the surface as well. The MMM Hypothesis and its predecessors were formulated to support the development of the fatigue strength assessment of the German FKM Guideline, in order to be able to utilize, among others, the Guideline material-related knowledge for non-proportional Components with load-free and fluid-loaded, smooth and Notched Component surfaces.
F V Antunes - One of the best experts on this subject based on the ideXlab platform.
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rapid assessment of multiaxial fatigue lifetime in Notched Components using an averaged strain energy density approach
International Journal of Fatigue, 2019Co-Authors: Ricardo Branco, Filippo Berto, L.p. Borrego, Jd Costa, P A Prates, Andrei Kotousov, F V AntunesAbstract:Abstract This paper proposes a rapid fatigue lifetime assessment approach to deal with Notched Components undergoing multiaxial loading. The modus operandi consists of calculating an effective quantity of the strain energy density nearby the crack initiation site of the Notched Component using an elastic-plastic numerical model. This quantity is then inserted into a fatigue master curve connecting the strain energy density with the number of cycles to failure to estimate the number of cycles to fatigue crack initiation. The proposed approach is applied to lateral U-shaped Notched round bars subjected to multiaxial in-phase loading histories. Both the experimental results and the numerical predictions are in good agreement.
Heinz Mertens - One of the best experts on this subject based on the ideXlab platform.
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a time dependent equivalent stress function for proportional and non proportional transient loaded and Notched metallic Components
International Journal of Fatigue, 2017Co-Authors: Heinz Mertens, Robert LiebichAbstract:Abstract The novel “Modified Mohr Mises” (MMM) Hypothesis allows the assessment of non-proportional stresses within a fully automated process, due to its invariant equivalent stress notation. Those non-proportional stresses are most common in complex structures of aircrafts, spacecrafts and vehicles for instance. The new MMM Hypothesis provides a physically reasonable sign determination derived directly from the effective stress Components. Supporting effects through material and adjacent material areas and local geometries are considered in the theory as well. The use of a suitable tension shear strength ratio allows a consideration of anisotropic material behavior in the surface as well. The MMM Hypothesis and its predecessors were formulated to support the development of the fatigue strength assessment of the German FKM Guideline, in order to be able to utilize, among others, the Guideline material-related knowledge for non-proportional Components with load-free and fluid-loaded, smooth and Notched Component surfaces.
Tatsuo Inoue - One of the best experts on this subject based on the ideXlab platform.
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fatigue behavior in Notched Component of α β and β titanium alloys under combined axial torsional loading
Journal of The Society of Materials Science Japan, 1995Co-Authors: Toshihiko Hoshide, Takatoshi Hirota, Tatsuo InoueAbstract:In the present study, fatigue tests under axial, torsional and combined axial-torsional loading were conducted using the cylindrical specimen with circumferential blunt notch of Ti-6Al-4V titanium alloys. Two kinds of alloys with different microstructure, the (α+β) and the β alloys, were investigated in the fatigue tests. The fatigue life was correlated with the range of equivalent plastic strain. In both alloys, the fatigue life for the same equivalent plastic strain became longer as increasing shear Component in the stress state at the notch root. The dominant surface cracks propagated in Mode I under the axial and combined loading in the two alloys. When the crack growth rate under the axial and combined loading was correlated with the range of J-integral, the result almost coincided with the growth relation for large through-thickness cracks in each material. Although the growth of Mode II type was predominant under the torsional loading, the growth direction of the main crack was the axial one in the (α+β) alloy, but the circumferential one in the β alloy. The cracking morphology depending on the microstructure, under the torsional loading, was simulated successfully by using a proposed model for crack initiation.
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residual life evaluation based on modeling of distributed small cracks in Notched Component subjected to cyclic combined loadings
Journal of The Society of Materials Science Japan, 1993Co-Authors: Toshihiko Hoshide, Eisaku Kakiuchi, Tatsuo InoueAbstract:A procedure to evaluate residual life under cyclic combined loadings was established for a given initial state of distributed small cracks. Distributed cracks at the initial stage were modeled as straight-line cracks by using an image-processing technique. The algorithm for the analysis of the crack growth after the initial stage was constructed by taking account of both modes of the propagation as a single crack and the coalescence between propagating cracks. Fatigue tests under combined axialtorsional loadings with constant and variable amplitudes were also conducted using cyclindrical specimens of pure copper with circumferential blunt notches. The fatigue life was correlated with the equivalent plastic strain range. When Compared for the same value of the parameter, the fatigue life became longer with increasing shear Component in the stress state at the notch root, while no significant difference was observed between two loading modes of constant and variable stress amplitudes. The fatigue life defined by the formation of crack with a specific length was evaluated based on the proposed procedure. The predicted life almost coincided with the experimental data. Cracking morphology was also simulated by using the present model to show good correspondence with experimental observations.
Ricardo Branco - One of the best experts on this subject based on the ideXlab platform.
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rapid assessment of multiaxial fatigue lifetime in Notched Components using an averaged strain energy density approach
International Journal of Fatigue, 2019Co-Authors: Ricardo Branco, Filippo Berto, L.p. Borrego, Jd Costa, P A Prates, Andrei Kotousov, F V AntunesAbstract:Abstract This paper proposes a rapid fatigue lifetime assessment approach to deal with Notched Components undergoing multiaxial loading. The modus operandi consists of calculating an effective quantity of the strain energy density nearby the crack initiation site of the Notched Component using an elastic-plastic numerical model. This quantity is then inserted into a fatigue master curve connecting the strain energy density with the number of cycles to failure to estimate the number of cycles to fatigue crack initiation. The proposed approach is applied to lateral U-shaped Notched round bars subjected to multiaxial in-phase loading histories. Both the experimental results and the numerical predictions are in good agreement.
