A computational iterative design method for bend-twist deformation in composite ship propeller blades for thrusters

This study investigates the feasibility of utilising common composite material layup techniques in ship propeller blade design to achieve an automatic pitch adjustment through bending-induced twist deformation. A comprehensive design approach, including various reinforcement materials and arrangements, was employed to attain the desired foil pitching, while minimising other undesirable deformation modes. The design process involved iterative computational analysis using finite element analysis and a deformation mode analysis based on foil shape parameters. The research showed that the proposed design approach effectively found options to improve the desired foil parameter pitch, while minimising undesirable deformation modes such as blade deflection and foil shape change. Furthermore, the proposed blade design was tested in thruster steering operational conditions and was found to have a pitch change well matched, potentially countering some changes in fluid flow. When compared to Kumar and Wurm's design, which only focused on the angular orientation of glass reinforcement, the proposed design was found to outperform the twisting by achieving the same twist for a blade half the length. This study provides valuable insights into the utilisation of composite materials in ship propeller design and highlights the potential for further improvement through a composite engineering design approach.