Modeling Approaches for Evaluating the Equivalent Mechanical Properties of Wind Turbine Blade Composites

Resumo

The objective of this paper is to conduct a systematic and critical assessment of four models used to calculate the structural and inertial properties of wind turbine blades, with particular emphasis on those made from composite materials. Although traditional 3D Finite Element Analysis offers high accuracy, it is computationally expensive. Consequently, reduced-order modeling approaches, particularly one-dimensional geometrically exact beam theories, are commonly employed. However, the accuracy of these simplified models depends on the fidelity of the sectional properties provided as input.This study analyzes and compares four modeling approaches, each implemented through a dedicated computational tool: PreComp, VABS, CROSTAB, and GXBeam. These models are evaluated based on their theoretical foundations, computational capabilities, assumptions, and limitations. PreComp, while efficient due to its simplified assumptions, may lack accuracy when applied to complex geometries or heterogeneous structures. VABS (Variational Asymptotic Beam Section analysis) is distinguished by its rigorous mathematical framework, enabling accurate computation of both one-dimensional beam properties and three-dimensional field distributions. CROSTAB offers high computational efficiency but is constrained by assumptions regarding material homogeneity and in-plane wall behavior. GXBeam employs a finite element-based formulation that accurately determines the mass and stiffness properties of composite sections with arbitrary geometry and anisotropic materials. Importantly, it captures all relevant geometric and material-induced couplings, including bend–twist interactions. In this work, the structural and inertial properties are computed using GXBeam. The results are then compared with those previously obtained from PreComp, VABS, and CROSTAB, which serve as reference data for the analysis of sectional properties.To evaluate the performance of these models, the paper presents a case study based on a realistic wind turbine blade featuring two distinct cross-sections, both derived from the MH 104 airfoil. Each cross-section is modeled with five outer skin segments and two internal webs, located at 15% and 50% of the chord length. The blade’s material layup is highly detailed and representative of industry standards. The complexity of this configuration necessitates models capable of accurately capturing anisotropic behavior and elastic couplings.