Development of a novel characterization model for innovative bionic helical carbon fiber tows

[Display omitted] The design of bionic helical structures significantly enhances load-bearing capacity and impact resistance, demonstrating great potential for mechanical property improvement. However, there is still a lack of precise characterization models for the helical structures of carbon fibers, which constrains their potential in engineering applications. This paper successfully fabricated helical carbon fiber tows using a carbon fiber twisting technique and introduced a novel intersecting circular cross-section model to thoroughly investigate the influence of the helical structure on the mechanical properties of carbon fiber tows. Tensile test results show that at a twist angle of 5°, the helical structure increases the tensile strength and fracture toughness of carbon fiber tows by 13.6% and 34.3%, respectively. Additionally, the introduction of complex structures such as helices significantly influences the material’s modulus, and precise modulus prediction is crucial for material optimization and practical application. Based on the newly proposed model, a modulus prediction model is developed, demonstrating higher predictive accuracy than traditional models with a prediction error of 2.8%. Finite element simulations further validate the practicality and superiority of the intersecting circular cross-section model. Compared to traditional models, the predictions of the novel model are closer to experimental data, with a prediction error below 2%, emphasizing the significant impact of microstructures on macroscopic properties and offering a new perspective for modeling complex material systems. These findings provide crucial theoretical and methodological support for the design and performance optimization of carbon fiber materials.