Metodologia para análise de sensibilidade e valores admissíveis de projeto em base B para resistência de laminados com furos circulares

Abstract

The increasing demand for predictions of crack behavior in composite materials has driven significant advancements in failure studies, particularly in the area of Linear Elastic Fracture Mechanics (LEFM). Traditional methods are based on Classical Laminate Theory (CLT) and the Tsai-Wu failure criteria, which address First Ply Failure (FPF) and Last Ply Failure (LPF), including their respective failure surfaces. However, these methods rely on multiple tests, resulting in significant costs. To overcome this limitation, an approach has been developed using the longitudinal modulus E1 as a single parameter to determine the elastic properties of laminates. This methodology not only simplifies testing procedures but can also be extended to predict the strength of notched laminates under tensile (Open-Hole Tension - OHT) and compressive (Open-Hole Compression - OHC) loadings. Despite the effectiveness of this approach, it still depends on several material parameters, such as longitudinal strength F1 and fracture toughness G0, as well as geometric factors like diameter D and width W. Therefore, this study aims to develop a finite fracture mechanics model to determine failure stresses in tension and compression (OHT and OHC), comparing the obtained results with data available in the literature and identifying the limitations of the applied method. The global sensitivity of failure stress is evaluated, considering different material systems and using Sobol indices. Finally, a surrogate model based on machine learning is proposed to generate B-basis design allowable values, aiming to reduce computational costs and accelerate the analysis process. The results indicate that the most influential parameters are laminate-dependent and are mainly governed by the hole diameter.