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1.
Johannes Ruck Yamen Othmani Tanja Lube Iyas Khader Andreas Kailer Thomas Böhlke 《PAMM》2015,15(1):147-148
Modeling the damage of brittle materials is of great importance considering a variety of structural components. Prominent examples are high strength engineering ceramics. The present work is concerned with silicon nitride, a material with increasing relevance in industrial applications. In the sense of a hierarchical model structure, effective properties of micromechanical simulations were applied to macroscopic, phenomenological damage models for monotonous and cyclic loading. In the following, both models are introduced and the application of the cyclic damage model to a four point bending test is discussed. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
In this paper, an implicit coupling algorithm for fluid–structure interaction problems with under-time steps for the solid
is presented. Its implementation on two configurations is achieved by using the CASTEM finite-elements code. First, the free
oscillations of a cylinder in an annular fluid domain where its movement is determined by the coupled fluid–solid action is
considered in the case of viscous fluid. It should be noted that the implicit coupling algorithm gives the best prediction
of the structure oscillations. The under-time steps for the solid are introduced in order to obtain better results. Then,
an application whose final objective is to model a floating barrage is studied. The main goal of this application is to predict
the displacements of a ring completely immersed and anchored by a cable to the lower boundary of the fluid domain. The finite-element
discretization of the Navier–Stokes equations in the ALE formulation is used 相似文献
3.
In this Note we present a justification of the kinematic assumptions for thin-walled rods with shallow profile. These assumptions are fundamental to writing the one-dimensional equilibrium equations for such structures. The obtained kinematics are different from the Vlassov case, which is only valid for strongly curved profiles. They are also different from the that classically used in shell theory. The justification given in this Note is based on an asymptotic approach. To cite this article: L. Grillet et al., C. R. Mecanique 333 (2005). 相似文献
4.
In order to preserve the physical properties of the flow (scaling laws, conservation laws, …) during the simulation, a class of subgrid models respecting the symmetry group of the Navier–Stokes equations is built. The class is then refined such that models satisfy the second law of thermodynamics and are suited to take into account the inverse energy cascade. A simple model belonging to the class is tested and a better result than those provided by Smagorinsky and dynamic models is obtained. To cite this article: D. Razafindralandy, A. Hamdouni, C. R. Mecanique 333 (2005). 相似文献
5.
In this paper, we present a non-linear one-dimensional model for thin-walled rods with open strongly curved cross-section, obtained by asymptotic methods. A dimensional analysis of the non-linear three-dimensional equilibrium equations lets appear dimensionless numbers which reflect the geometry of the structure and the level of applied forces. For a given force level, the order of magnitude of the displacements and the corresponding one-dimensional model are deduced by asymptotic expansions. 相似文献
6.
As sulfur dioxide (SO2) is often involved in combustion processes, we present here SO2-concentration measurements in the post-flame region of a CH4/air/SO2 premixed flame. SO2 concentrations were deduced from high-resolution absorption spectra recorded with a mid-infrared tunable diode-laser (TDL)
source operating at liquid nitrogen temperature. Single-mode, continuous frequency tuning around 1384.5 cm-1 (or 7.5 μm) is achieved by a fine TDL temperature ramp. These experiments lead us to develop in situ combustion-pollutant
measurements with compact apparatus. We show that this non-intrusive method is efficient for detection and allows the retrieval
of SO2 concentration and temperature.
Received: 19 February 2001 / Revised version: 18 April 2001 / Published online: 7 June 2001 相似文献
7.
N. Jacquinet-Husson N.A. Scott K. Garceran A.A. Chursin M. Birk C. Camy-Peyret C. Clerbaux P.F. Coheur L. Daumont J.M. Flaud A. Hamdouni D. Jacquemart J.Y. Mandin S. Mikhailenko A. Nikitin A. Perrin L. Régalia-Jarlot F. Schreier K.M. Smith J.L. Teffo Vl.G. Tyuterev P. Varanasi 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,95(4):429-467
The content of the current (2003) version, GEISA/IASI-03, of the computer-accessible spectroscopic database, GEISA/IASI, is described. This “system” or database is comprised of three independent spectroscopic archives, which are (a) a database of individual spectral line parameters on 14 molecules, H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, HNO3, OCS, C2H2, N2, and the related 51 isotopomers and isotopologues, representing 702,550 entries, in the spectral range 599-, (b) a database of spectral absorption cross-sections (6,572,329 entries related to six molecules, CFC-11, CFC-12, CFC-14, HCFC-22, N2O5, CCl4), and a catalogue of microphysical and optical properties (mainly, the refractive indices) of atmospheric aerosols. The modifications and improvements, which have been implemented since the earlier editions of this database, in terms of content and management, have been explained in detail. GEISA/IASI has been created with the specific purpose of assessing the capability of measurement by the IASI instrument within the designated goals of ISSWG in the frame of the CNES/EUMETSAT European Polar System preparation.All the archived data can be handled through a user-friendly associated management software, which is posted on the ARA/LMD group web site at http://ara.lmd.polytechnique.fr. 相似文献
8.
The aim of this communication is to show the ability of POD to compute the instantaneous flow velocity when applying the Lagrangian
technique to predict particle dispersion. The instantaneous flow velocity at the particle's location is obtained by solving
a low-order dynamical model, deduced by a Galerkin projection of the Navier-Stokes equations onto each POD eigenfunction and
it is coupled with the particle's equation of motion. This technique is applied to particle dispersion in a three-dimensional
lid driven cavity. It yields a substantial decrease in computing time in comparison with LES computation and it enables treating
different cases of particle dispersion
Published in Prikladnaya Mekhanika, Vol. 44, No. 1, pp. 133–142, January 2008. 相似文献
9.
10.
Symmetries have an important role in turbulence. To some extent, they contain the physics of the equations (conservation laws,
etc.), and it is essential that turbulence models respect them. However, as observed by Oberlack (Annual Research Briefs.
Stanford University, Stanford 1997) and next by Razafindralandy and Hamdouni (Direct and Large-Eddy Simulation 6: Proceedings
of the 6th International ERCOFTAC Workshop on Direct and Large-Eddy Simulation. Springer, Heidelberg, 2006) in the case of
an isothermal fluid, only few subgrid stress tensor models preserve the symmetries of the Navier–Stokes equations. In this
communication, we present the symmetries of the equations of a non-isothermal fluid flow and analyze some common subgrid stress
tensor and flux models under the point of view of these symmetries.
相似文献