Fatigue lifespan of a fillet welded joint - Hybrid approach to obtain the S-N curve with a reduced number of tests

Abstract

This paper 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 according Zhao et al. 1998 , 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.

Probabilistic S-N fields based on statistical distributions applied to metallic and composite materials: State of the art

“…The ASTM-E739 standard is widely applied to analyze the experimental fatigue life results of metals based on log-normal statistical distribution to estimate the confidence bands for the S-N and e-N curves. [40][41][42][43][44][45] Correia et al 46 have used in its research work this ASTM standard with the purpose of generating the design curves for fatigue crack growth (FCG) rates applied to old steel bridges materials, demonstrating the applicability of this methodology to other laws. Raposo et al 47 presented a methodology to generate P-S-N curves applied to the structural and mechanical components, based on the FCG modeling as a process of successive crack re-initiations, using local fatigue damage parameters (e.g.…”