| Abstrakt: |
As the research on composite materials based on natural resources proliferates further, ramie fiber and polylactic acid (PLA), whch are fully biodegradable composite materials, are expected to be used for mechanical application due to their excellent strength and degradability. Various natural fibers have been applied to a wind turbine blade composite structure, as reinforcement material. However, none of them are fully biodegradable, as the matrix still uses synthetic resins. Hence, this study aims to theoretically optimize the fully biodegradable ramie/PLA laminate design using its lamina orientation on a taper-less blade shell of a wind turbine, as the operating structure experienced multiaxial loading through bending and torsional moment derived by the wind. The selection of taper-less blades was made due to their congruence with the wind speed categorization in southeastern Indonesian territory. The optimization was carried out using the nonlinear Generalized Reduced Gradient (GRG) method on Microsoft Excel. The optimized laminate result is in a stacking sequence of [-4°, 24°, 47°, 65°, 74°, 79°]S that delivers the factor of safety, which is the ratio between the allowable stress and the actual stress, of 7.296 and 18.057 on the longitudinal axis and the laminate shear-plane, respectively, This renders the composite laminate highly safe, both theoretically and numerically. [ABSTRACT FROM AUTHOR] |
