Evaluation of Bend-Twist Coupling in Shape Memory Alloy Integrated Fiber Rubber Composites

  • Annadata, Achyuth Ram (ITM, TU Dresden)
  • Endesfelder, Anett (Fraunhofer IWS)
  • Koenigsdorf, Markus (IFE, TU Dresden)
  • Mersch, Johannes (ITM, TU Dresden)
  • Gereke, Thomas (ITM, TU Dresden)
  • Zimmermann, Martina (Fraunhofer IWS)
  • Cherif, Chokri (ITM, TU Dresden)

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The aim of this project is to evaluate the bend-twist coupling in the Interactive Fiber Rubber Composites. The term interactive in this context implies a sheathed SMA wire stitched onto the textile fibers with the help of TFP method, which when activated, induces a contraction force resulting in bending and twisting of the composite. The reinforced composite is made of polydimethylsiloxane (PDMS) and has two layers of glass fibers stacked upon one another and joined with the help of TFP machine. The bottom layer is a 0°/90° woven fabric and the top layer has segment combination of 0°/90° woven fabrics and 45° unidirectional (UD) fibers. The sheathed SMA wire is stitched on the top layer and has a U-shape with the curved bend positioned on the UD fibers ensuring the maximum force to act in the composite when activated. This work also focuses on the simulation of this approach in ANSYS Workbench with a user-defined material model for SMA paving for a comparative study with experimental results of the deformation and twisting angles. The importance of this model is that the shape memory effect can be achieved for different profiles of SMA, thus eliminating the necessity for a pre-stretch in contrast to the built-in model. As a sheath around the SMA, a cylindrical nylon tube with elastic properties is considered to replicate the behavior of PA yarns. The experimental values are evaluated from Multi-DIC technique, which is capable of determining deformations with respect to all directions. The derived conclusions are to be helpful in obtaining and evaluating 3D spatial movements in IFRC structures with multiple joints in the future projects.