Estimativa da tenacidade à fratura conforme a ASTM E1820 via elementos finitos

Abstract

The need to understand and predict the behavior of materials under crack propagation remains a continuous challenge, especially in critical applications where failures can lead to severe consequences. The traditional approach, based on experimental testing, presents practical limitations such as the requirement for specific specimen geometries, which hinders its application in certain contexts. To overcome these challenges, this study proposes an alternative approach based on numerical simulations using the Finite Element Method (FEM), implemented through the Abaqus software. The main objective is to develop and validate a numerical methodology capable of replicating and, when necessary, replacing experimental tests for the determination of JIC. Based on previous experimental results of fracture toughness obtained from compact tension C(T) specimens made of AISI 4340 steel at 28 HRC and 40 HRC, it is possible to structure the simulation with appropriate boundary conditions and compare the simulated results with the experimental data. The development includes modeling the specimen geometry, implementing the material's tensile mechanical properties, and calibrating the model based on load-displacement curves and JIC values. The proposed methodology is applied to estimate the fracture toughness of two steels used in the manufacturing of reinforcement wires. The results obtained show that finite element simulations are effective for determining fracture toughness in accordance with the ASTM E1820 standard, as the simulated JIC values are consistent with the experimental data. The systematic error associated with the simulated JIC values is -12.5 kJ/m² for AISI 4340 at 40 HRC and -12.33 kJ/m² for AISI 4340 at 28 HRC, indicating a high degree of accuracy in the simulated fracture toughness values. This approach not only proves to be economically advantageous but also expands the possibilities for analysis in situations where physical testing would be unfeasible. This study contributes to the advancement of material characterization practices, promoting greater safety and efficiency in the development and prediction of the mechanical properties of engineering materials, thus enabling designers to more quickly and appropriately select potential materials.