Theorical study on mechanical properties of AZ31B Magnesium alloy Sheets under multiaxial loading

Numerical simulation by plastic deformation of the shaping processes currently has a large industrial interest. It allows you to shorten the time of design and construction related products and tools to analyze and to optimize processes. An essential part of simulation tools is the constitutive law used to describe the material used. The activity of characterization and modeling of material behavior of the plastic deformation shaping remains a very important research field of activity; the objective of proposing laws of behavior used in computer codes, essentially based on finite element is sufficiently to represent the real behavior of materials. Considering the nature of the materials used and the stresses they experience the behavior laws account for several requirements which make them increasingly complicated. Among these requirements, we cite in particular plastic anisotropy, the great transformations, the complexity and diversity of loads, etc. The complexity of these laws makes them more difficult to implement and in particular to identify: the classic tests are no longer sufficient for identification. The objective of this work is based on two essential points: Suggest a construction strategy, particularly of identifying laws elastoplastic behavior anisotropic operational for the numerical simulation of plastic deformation shaping processes with particular attention to sheet metal magnesium. Magnesium sheet metal manufacturing process involves rolling operation. In a cost-cutting goal, this operation now takes place cold, implying a very marked anisotropy of the material at the output of the mill.&nbsp

A new efficient Bayesian parameter inference strategy: Application to flow and pesticide transport through unsaturated porous media

International audienc

Fluid-structure interaction of a 7-rods bundle: Benchmarking numerical simulations with experimental data

Fluid flows through rod bundles are observed in many nuclear applications, such as in the core of Gen IV liquid metal fast breeder nuclear reactors (LMFBR). One of the main features of this configuration is the appearance of flow fluctuations in the rod gaps due to the velocity difference in the sub-channels between the rods. On one side, these pulsations are beneficial as they enhance the heat exchange between the rods and the fluid. On the other side, the fluid pulsations might induce vibrations of the flexible fuel rods, a mechanism generally referred to as Flow Induced Vibrations (FIV). Over time, this might result in mechanical fatigue of the rods and rod fretting, which eventually can compromise their structural integrity. Within the SESAME framework, a joint work between Delft University of Technology (TU Delft), Ghent University (UGent), and NRG has been carried out with the aim of performing experimental measurements of FIV in a 7-rods bundle and validate numerical simulations against the obtained experimental data. The experiments performed by TU Delft consisted of a gravity-driven flow through a 7-rods, hexagonal bundle with a pitch-to-diameter ratio P/D=1.11. A section of 200 mm of the central rod was made out of silicone, of which 100 mm were flexible. Flow measurements have been carried out with Laser Doppler Anemometry (LDA) whereas a high-speed camera has measured the vibrations induced on the silicone rod. The numerical simulations made use of the Unsteady Reynolds-averaged Navier-Stokes equations (URANS) approach for the turbulence modelling, and of strongly coupled algorithms for the solution of the fluid-structure interaction (FSI) problems. The measured frequency of the flow pulsations, as well as the mean rod displacement and vibration frequency, have been used to carry out the benchmark.RST/Reactor Physics and Nuclear Material