The Experts below are selected from a list of 16488 Experts worldwide ranked by ideXlab platform
Camille A Issa - One of the best experts on this subject based on the ideXlab platform.
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preliminary study on interfacial bond strength due to successive casting lifts of self consolidating concrete effect of thixotropy
Construction and Building Materials, 2016Co-Authors: Joseph J Assaad, Camille A IssaAbstract:Abstract Vibration is prohibited during placement of freshly mixed self-consolidating concrete (SCC), making it particularly sensitive to delays or stoppages during multi-layers casting. This paper seeks to propose suitable testing methods that can be used to assess the effect of delays between successive lifts on interfacial bond strength of Hardened Material, including the proposal of time limits necessary to ensure proper mixing of cast layers. Two methods for testing bond by slant shear and pull-off are tested and compared. The SCC mixtures were proportioned to exhibit low to high thixotropic levels, while the relative delay between cast layers was set to 30, 60, and 120 min after initial mixing. Test results have shown that the lowest drop in interfacial bond strength occurred for moderately thixotropic mixtures, given the moderate bleeding rate that prevented dryness of the first cast layer while, at the same time, avoided excessive increase in water that reduces bond strength development along the interfaces.
Philippe Bristiel - One of the best experts on this subject based on the ideXlab platform.
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simulation of multiaxial fatigue strength of steel component treated by surface induction hardening and comparison with experimental results
International Journal of Fatigue, 2011Co-Authors: Thierry Palinluc, Dominique Coupard, C Dumas, Philippe BristielAbstract:Abstract This paper proposes a method to assess the high-cycle multiaxial fatigue strength of components treated by surface induction hardening (SIH). Surface quenching following surface induction heating is simulated, taking into account the following features of the process: (i) electromagnetic and thermal fields, (ii) phase transformation, and (iii) the residual stress field resulting from the entire process. The fatigue strength of the specimens was simulated using Crossland and Dang-Van criteria; the field of the residual stresses and the fatigue characteristics of both the untreated Material and the treated layer (martensite) are considered. Fatigue tests on smooth specimens were carried out to compare simulated results with experimental data. These tests yield information regarding the influence of the thermal treatment on Material behaviour and strength, including microstructure evolution and mechanical characteristics, especially in fatigue. For this purpose, residual stresses were analyzed by X-ray diffraction before and after the fatigue tests. Fatigue crack initiation areas (at the specimen’s surface or below) are predicted depending on the depth of the Hardened Material layer. The simulation of the fatigue strength at 2 × 106 cycles is in good agreement with experimental results.
E Elmagd - One of the best experts on this subject based on the ideXlab platform.
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description of the creep behaviour of the precipitation Hardened Material al cu mg alloy 2024 using finite element computations based on microstructure mechanical models
Computational Materials Science, 1996Co-Authors: J Du Nnwald, E ElmagdAbstract:Abstract Precipitation-Hardened Materials change their microstructure during creep exposure which not only affects the shape of the creep curve but also the rupture time. This effect can be clearly shown on ageable aluminium alloys like Duralumin 2024 (Al-Cu-Mg). The goal of the numerical simulation of the Materials behaviour under high temperature conditions is to describe the creep response under special consideration of internal back-stress and precipitation kinetics, and to implement corresponding microstructural parameters into an FEM programme. Thus a finite element programme was developed which simulates creep behaviour by taking structure mechanics into consideration.
Mirko Schaper - One of the best experts on this subject based on the ideXlab platform.
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short austenitization treatment with subsequent press hardening correlation between process parameters microstructure and mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Olexandr Grydin, Anatolii Andreiev, Martin Joachim Holzweisig, Christian Johannes Rusing, Kristina Duschik, Yaroslav Frolov, Mirko SchaperAbstract:Abstract This study discusses contact heating of blanks as a time- and cost-saving alternative to conventional heating in radiation furnaces for press hardening of high-strength car body elements. Different from radiation furnaces, where the process takes up to 10 min, contact heating allows to austenitize the Material within seconds. Various experimental series were carried out to investigate the influence of short austenitization on the microstructure and resulting mechanical properties after subsequent press hardening. Attention was given to the individual effects on the relevant processing parameters of the production chain “contact heating – press hardening”. Those include thickness and initial state of the Material, cooling rate as well as the presence of post-treatment (cathodic dip coating). The obtained results were compared both to the conventionally austenitized and press-Hardened Material as well as to the requirements of the industrial standard. Finally, the feasibility of the process was proven by considering the example of press hardening of a door impact beam.
Joseph J Assaad - One of the best experts on this subject based on the ideXlab platform.
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preliminary study on interfacial bond strength due to successive casting lifts of self consolidating concrete effect of thixotropy
Construction and Building Materials, 2016Co-Authors: Joseph J Assaad, Camille A IssaAbstract:Abstract Vibration is prohibited during placement of freshly mixed self-consolidating concrete (SCC), making it particularly sensitive to delays or stoppages during multi-layers casting. This paper seeks to propose suitable testing methods that can be used to assess the effect of delays between successive lifts on interfacial bond strength of Hardened Material, including the proposal of time limits necessary to ensure proper mixing of cast layers. Two methods for testing bond by slant shear and pull-off are tested and compared. The SCC mixtures were proportioned to exhibit low to high thixotropic levels, while the relative delay between cast layers was set to 30, 60, and 120 min after initial mixing. Test results have shown that the lowest drop in interfacial bond strength occurred for moderately thixotropic mixtures, given the moderate bleeding rate that prevented dryness of the first cast layer while, at the same time, avoided excessive increase in water that reduces bond strength development along the interfaces.
