Abstract This work presents a new computational approach to estimate the fatigue life in welded joints, taking into account three-dimensional, non-proportional, and out-of-phase stresses; the thermomechanical properties of steel; parameters of the welding process; and the effects of residual stresses. We use the mechanical equations of continuous and cumulative fatigue damage found from Multiaxial RainFlow, the Wang and Brown and critical plane methods, and the Findley criteria approach. The numerical finite element method, available with software, is used to simulate the formation of residual stress and quantify its influence by solving equations. Based on the analysis of numerical results, we were able to prevision the crack location and angles of propagation of a high cycle fatigue crack with totally random loads in a metallic structure. We conclude that the result of the computational method is valid and can be used to estimate and life in fatigue in welded joints.

Resumo O principal objetivo deste trabalho é mostrar aos especialistas envolvidos com estruturas soldadas submetidas a esforços cíclicos uniaxiais e multiaxiais, proporcionais ou não proporcionais, as opções existentes para previsão de vida em fadiga para juntas soldadas. Apresentam-se as normas, Eurocode 3 - IIW- AASHTO e BS 5400, com suas características específicas e uma revisão das metodologias computacionais desenvolvidas nos últimos anos. Para avaliar as normas apresentadas, analisa-se dois casos de previsão de vida em fadiga, uma chapa e uma viga I, nas diferentes normas. Identificou-se as similaridades e discrepâncias entre as normas, acerca dos principais parâmetros constitutivos, a previsível semelhança entre as previsões de vida em fadiga obtidas via IIW e Eurocode 3 e as significativas diferenças entres AASHTO e BS 5400 em decorrência da filosofia de cada norma.

Abstract The main objective of this work is to show to the specialists involved welded structures subjected to cyclic uniaxial and multiaxial stresses proportional or non-proportional to the existing options for fatigue life prediction for welded joints that deals with the subject. Each of the standards (Eurocode 3 - IIW-AASHTO and BS 5400) has specific characteristics, some of them very distinct as well as a review of the computational methodologies developed in recent years. To evaluate the standards presented a case of fatigue life prediction of a plate top in I -beam I in the different standards. The similarities and discrepancies between the standards, the main constitutive parameters, the predicted similarity between fatigue life forecasts obtained through IIW and Eurocode 3, and the significant differences between AASHTO and BS 5400 were identified as a result of the philosophy of each standard.