I am Anna-Maria Persson and I started my PhD at the 1st of February this year. My study is related to the field of mechanical properties of thermoplastic elastomers in injection moulded components. My PhD is a SINTEF Material and Chemistry funded industrial PhD, associated to SFI Manufacturing and admitted by NTNU.
I started my PhD with experimental studies of the elasto-visco-plastic response of a novel but commercialised thermoplastic elastomer prepared by vulcanization (TPV). One significant aspect is sample preparation and geometry (figure 1), and another is handling and treating the experimental data (strain) output. As the experimental methodology in itself is a target for the PhD, a selected few more materials will be studied subsequently.
I started my PhD with experimental studies of the elasto-visco-plastic response of a novel but commercialised thermoplastic elastomer prepared by vulcanization (TPV). One significant aspect is sample preparation and geometry (figure 1), and another is handling and treating the experimental data (strain) output. As the experimental methodology in itself is a target for the PhD, a selected few more materials will be studied subsequently.
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Figure 1A and 1B: Speckle patterns for digital image correlation giving 3D field strain measurements of cyclic compression tests.
In parallel, materials models are intended calibrated and verified, primarily for a selection of published material models, including behavioural features of non-linear nature and time-temperature dependency. I am currently immerged in 10-15 years of publications of rubber and elastomer material models. One major challenge is to adequately describe the complex mechanical response with a model also suitable for industrial use. Figure 2 is an example of one characteristic of elastomer mechanical response.
In parallel, materials models are intended calibrated and verified, primarily for a selection of published material models, including behavioural features of non-linear nature and time-temperature dependency. I am currently immerged in 10-15 years of publications of rubber and elastomer material models. One major challenge is to adequately describe the complex mechanical response with a model also suitable for industrial use. Figure 2 is an example of one characteristic of elastomer mechanical response.
 Figure 2: Hysteresis effect, a visco-plastic-elastic type of response during cyclic tensile loading. |  Figure 3: Residual stresses in conventional rubber o-rings initially after assembly. |
During my PhD, I will have a close dialogue with Kongsberg Automotive's Couplings division to get the valuable industrial view feedback (figure 4). To develop a response on how an integrated, free-geometry elastomer sealing can compete with a conventional o-ring in a demanding application, the material models will be used in simulation of two component injection moulded sealings. After this, the elastomer sealing performance needs to be related to the performance of a conventional rubber sealing (figure 3.)
 Figure 4: Henning Ruud and Geir Liakleiv, Kongsberg Automotive (Foto: i4plastics) |  Anna-Maria Persson |
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