Estimation of fatigue S-N curves of welded joints using advanced probabilistic approach

Abstract This paper provides a new advanced probabilistic approach for reliable estimation of the fatigue characteristic S-N curves of welded joints both for constant amplitude (CA) and variable amplitude (VA) loading conditions. The presented approach, which is referred to as the ML-MCS approach, combines Maximum Likelihood method (ML) and Monte-Carlo Simulations (MCS) method to estimate true p-quantiles of CA and VA S-N curves by using complete experimental data-sets. The ML-MCS approach includes a linearization method for use of S-N curves in combination with linear damage accumulation rule as well as for direct comparison with current standards. Application of the ML-MCS approach on two study cases and comparison with current standards shows that the use of the ML-MCS approach may have a significant impact in re-definition of CA and VA S-N curves of current standards and in particular of the CAFL, of the S-N curve second slope and of the critical value of accumulated damage at failure. The last section of the paper provides accurate guidelines for future experimental tests needed for re-definition of current standards.

[1]  William Q. Meeker,et al.  Estimating Fatigue Curves With the Random Fatigue-Limit Model , 1999, Technometrics.

[2]  E. Haibach,et al.  THE METHOD OF MAXIMUM LIKELIHOOD APPLIED TO THE STATISTICAL ANALYSIS OF FATIGUE DATA INCLUDING RUN-OUTS , 1979 .

[3]  Russell B. Millar,et al.  Maximum Likelihood Estimation and Inference: With Examples in R, SAS and ADMB , 2011 .

[4]  Dimitris Diamantidis,et al.  The Joint Committee on Structural Safety (JCSS) Probabilistic Model Code for New and Existing Structures , 1999 .

[5]  W Nelson,et al.  Fitting of fatigue curves with nonconstant standard deviation to data with runouts , 1984 .

[6]  A. Hobbacher.  Recommendations for fatigue design of welded joints and components , 2016 .

[7]  Alain Nussbaumer,et al.  Fatigue Design of Steel and Composite Structures: Eurocode 3: Design of Steel Structures, Part 1-9 Fatigue; Eurocode 4: Design of Composite Steel and Concrete Structures , 2011 .

[8]  Michael Vormwald,et al.  Consideration of Fatigue Damage Below the Endurance Limit in Life Predictions for Variable Amplitude Loading , 1990 .

[9]  Gary Marquis,et al.  LONG LIFE SPECTRUM FATIGUE OF CARBON AND STAINLESS STEEL WELDS , 1996 .

[10]  Luca DAngelo,et al.  Experimental fatigue tests of in-plane welded gusset joints , 2015 .

[11]  Christoffer Astrup,et al.  Fatigue of Welded Structures , 2009 .

[12]  S. J. Maddox,et al.  Investigation of fatigue damage to welded joints under variable amplitude loading spectra , 2009 .

[13]  E. W. C. Wilkins,et al.  Cumulative damage in fatigue , 1956 .

[14]  C. Sonsino.  Course of SN-curves especially in the high-cycle fatigue regime with regard to component design and safety , 2007 .

[15]  S Berge,et al.  Residual Stress and Stress Interaction in Fatigue Testing of Welded Joints , 1982 .

[16]  Alain Nussbaumer,et al.  RESISTANCE OF WELDED DETAILS UNDER VARIABLE AMPLITUDE LONG-LIFE FATIGUE LOADING , 1993 .

[17]  Naman Recho,et al.  Fatigue behavior of welded joints Part 1 - statistical methods for fatigue life prediction : A model is investigated where fatigue life and fatigue limit are treated as random variables , 2005 .

[18]  C G Schilling,et al.  Fatigue of welded steel bridge members under variable-amplitude loadings , 1978 .

[19]  Kentaro Yamada,et al.  Simulation of Service Fatigue Loads for Short-Span Highway Bridges , 1979 .