Applications of Griffith's equation in the study of cracks developed in mechanical elements subject to axial stresses, working under accelerated aging conditions

Abstract

Mechanical components often suffer fractures due to porosities that form and become cracks due to stress and exposure to the environment, especially when working in aggressive environments. Because of this, it is necessary to study and simulate the aspects that cause these fractures in the first place and thus understand how they develop and spread. Fracture mechanics is usually applied when the component is already on the verge of failure, using finite element analysis to evaluate the fracture behavior, however, it is also essential to analyze the previous stages to forecast the remaining service life and evaluate corrosion factors from the environment. The external variables include UV radiation, temperature, and humidity, while the internal variables are mechanical properties of the material. The expected degradation is represented as a function of time and these variables. The maximum acceptable stress and maximum allowable crack length are calculated to determine whether the component is safe. Some case studies in AISI 4140  ferrous materials are presented, where the degradation was measured at the periphery of a specimen and the degradation trend was calculated, as well as the study of finite element analysis, in order to identify the maximum main processes surrounding the crack boundaries