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    <title>Auteurs : Bojan Starman</title>
    <link>https://popups.uliege.be/esaform21/index.php?id=2347</link>
    <description>Publications of Auteurs Bojan Starman</description>
    <language>fr</language>
    <ttl>0</ttl>
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      <title>Parameters' Confidence Intervals Evaluation for Heterogeneous Strain Field Specimen Designs by Using Digital Image Correlation </title>
      <link>https://popups.uliege.be/esaform21/index.php?id=2415</link>
      <description>This paper aims to compare different heterogeneous test designs from the perspective of the confidence interval quantification of inversely identified parameters, where the influence of a DIC optical system systematic and random error are taken into account. Because the errors in optical measurement can arise from many reasons and sources, our methodology relies on the system's errors determined from initial sets of pictures acquired at the load-free state for hundreds of specimens (over 850 tests over the past three years). In this way, a prior probability distribution of systematic and random error, arisen from the system initial settings and testing procedures are determined. Further, by conducting an inverse identification procedure of linear orthotropic elastic material parameters, the influence of the error distributions is studied for different types of heterogeneous specimens. The presented methodology determines the DIC bias and random error propagation through the inverse identification procedure to individual parameters. For each specimen design, confidence intervals of identified material parameters were determined. The results show the appropriateness of a specimen design for the identification of particular material parameters.  </description>
      <pubDate>Tue, 23 Mar 2021 18:30:15 +0100</pubDate>
      <lastBuildDate>Mon, 29 Mar 2021 20:00:09 +0200</lastBuildDate>
      <guid isPermaLink="true">https://popups.uliege.be/esaform21/index.php?id=2415</guid>
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      <title>Advanced computational modelling of metallic wire-arc additive manufacturing </title>
      <link>https://popups.uliege.be/esaform21/index.php?id=2340</link>
      <description>Wire-arc welding-based additive manufacturing (WAAM) is a 3D printing technology for production of near-net-shape parts with complex geometry. This printing technology enables to build up a required shape layer by layer with a deposition of a consumable welding wire, where the welding arc is a source of heat. Welding is usually performed by CNC-controlled robotic manipulator, which provides a controlled location of material layer adding. Because the process itself involves thermo-mechanically complex phenomena, Finite Element-based virtual models are commonly employed to optimize the process parameters. This paper presents advanced computational modelling of the WAAM of a tube. A thermo-mechanical numerical model of the process is calibrated against experimental data, measured as temperature variation at the acquisition point. The virtual modelling starts with a preparation of the tube geometry in CAD software, where the geometry of the single-layer cross-section is assumed. The geometry is then exported to a G-code format data file and used to control robotic manipulator motion. On the other side, the code serves as an input to in-house developed code for automatic FEs activation in the simulation of the material layer-adding process. The time of activation of the finite elements (FEs) is directly related to the material deposition rate. The activation of the FEs is followed by a heat source, modeled with a double ellipsoidal power density distribution. The thermo-mechanical problem was solved as uncoupled to speed-up computation.  </description>
      <pubDate>Tue, 23 Mar 2021 17:02:11 +0100</pubDate>
      <lastBuildDate>Mon, 29 Mar 2021 19:26:36 +0200</lastBuildDate>
      <guid isPermaLink="true">https://popups.uliege.be/esaform21/index.php?id=2340</guid>
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