The development of wind turbines for regions with low wind speeds imposes a challenge to the expansion of the corresponding energy generation capacity. The present work consists of an evaluation of the potential carded jute fiber and jute yarn to be used in the construction of a wind blade for regions of low wind intensity. The fibers used were supplied by Company Textile of Castanhal (Castanhal-Para-Brazil) and used in the study without chemical treatment in the form of single-filament fibers and yarns with a surface twist of 18.5°. The composites were produced through the resin infusion technique and underwent tensile and shear tests using 120-Ohm strain gauges and a blade extensometer to obtain the Young’s modulus. In the analysis of the results, the ANOVA test was applied with a 0.05 significance level, followed by Tukey’s test. The results showed that long, aligned jute fibers can be a good option for laminated structures applied in composites for small wind turbine blades.

This study presents the development and mechanical characterization of a full-scale helmet manufactured from a polyester matrix composite reinforced with woven jute fabric using vacuum infusion. Laminates with two and four reinforcement layers were produced and assembled using four joining configurations: seamless, stitched, bonded, and hybrid (bonded + stitched). Tensile tests were performed according to ASTM D3039, while frontal and lateral compression tests followed ABNT NBR 7471, aiming to evaluate the influence of laminate thickness and joining strategy on mechanical performance. In tension, the seamless configuration reached maximum loads of 0.80 kN (two layers) and 1.60 kN (four layers), while the hybrid configuration achieved 0.79 kN and 1.43 kN, respectively. Stitched and bonded joints showed lower strength. Under compression, increasing the laminate thickness from two to four layers reduced frontal elongation from 15.09 mm to 9.97 mm and lateral elongation from 13.73 mm to 7.24 mm, corresponding to stiffness gains of 50.3% and 87.3%, respectively. Statistical analysis (ANOVA/Tukey, α = 0.05) confirmed significant effects of thickness and joint configuration. Although vacuum infusion is a well-established process, the novelty of this work lies in its application to a full-scale natural-fiber helmet, combined with a systematic evaluation of joining strategies and a direct correlation between standardized tensile behavior and structural compression performance. The four-layer hybrid laminate exhibited the best balance between strength, stiffness, and deformation capacity.

Natural fiber-reinforced polymer composites have been increasingly investigated for sustainable structural applications, including small wind turbine blades operating under low wind-speed conditions. However, despite their environmental advantages, there is a lack of experimental validation of structural models applied to real aerodynamic blade geometries manufactured with carded natural fibers, whose intrinsic fiber dispersion and microstructural heterogeneity challenge classical laminate-based approaches. The objective of this study is to evaluate the structural performance, modeling validity, and manufacturing feasibility of a small wind turbine blade produced from polyester resin reinforced with carded jute fibers, combining Classical Laminate Theory (CLT), additive-manufactured tooling, vacuum infusion processing, and quasi-static bending experiments. A 3D-printed ABS mold was used to manufacture an S1210 aerodynamic profile, enabling a low-cost and rapid tooling approach aligned with current trends in digital composite prototyping. The blade was structurally modeled using CLT with elastic properties obtained from previous experimental characterization and was experimentally evaluated through quasi-static bending tests instrumented with strain gauges at three spanwise stations. Numerical predictions showed strong agreement with experimental strain measurements, validating the applicability of CLT to carded natural-fiber laminates despite their inherent angular dispersion and microstructural variability. All monitored regions exhibited fully linear elastic behavior, with maximum stresses of approximately 5 MPa—well below the composite tensile strength (~60 MPa)—resulting in a safety factor close to 12. These results confirm the structural reliability, manufacturing feasibility, and sustainability potential of jute-reinforced polyester composites for small wind turbine blades operating in low-wind-speed environments (<2 m/s).