Modelo híbrido para obtenção de curvas de S-N com número de ensaios reduzidos

Abstract

Welded joints have great importance in the fatigue analysis of structures subjected to cyclic loading, being that design engineers and industries have interest in reliable methods that can be used to obtain the parameters for the fatigue analysis, such as the materials properties and methods for obtaining the stresses in the welded regions, in order to determine the life cycle of the structure or mechanical component with adequate reliability. This work introduces a hybrid approach for obtaining S–N curves with reduced number of tests associated to statistically simulated data. In order to validate the proposal, two validation process were developed. One using a methodology to generate S–N curves based on Monte Carlo simulations and other using actual data available in the literature, allowing to compare the hybrid approach with the experimental curve S–N obtained with high replication. In both validation process, a good accuracy was verified. Subsequently, the fatigue analysis of a fillet welded joint was carried out using finite element analysis to evaluate the cumulative damage and fatigue life, enabling comparison between the proposed method and standard NBR 8800: 2008. The results obtained with the proposed methodology allowed more accuracy results and less conservative than standard for the same weld detail class, both for fatigue life and for cumulative fatigue damage evaluations.