New Analysis Capabilities for Fatigue Life of Welded Components

Welding is often necessary in product design and production, but it can lead to susceptibility to fatigue cracking.  Predicting the fatigue life of welded components is therefore critical to ensuring product durability requirements are met. 

A number of analytical approaches have been used predict to weld durability.  These existing methods may struggle to accurately predict fatigue life in some cases.  This is particularly true in cases of complicated weldments and advanced materials that have become more prevalent in the current lightweighting environment.  In some weldments, cracks may initiate but grow very slowly – or not at all – depending on how the weld is designed.  Understanding the total life of the weld becomes very important to ensuring product durability.

The WholeLife fatigue method in nCode DesignLife addresses this analysis gap, bringing powerful new analysis capabilities for a more accurate prediction of weld fatigue life that results in improved product durability, reduced overdesign, and lower weight and cost.  WholeLife uses an integrated approach to model fatigue over the entire lifetime of the component – from very early stages of crack initiation to macroscopic crack growth and final fraction – to give a more accurate determination of weld life.  This combined approach of crack initiation and crack growth overcomes limitations and assumptions that are inherent in adopting either of these approaches separately.

SAE International’s Fatigue Design and Evaluation (FD&E) committee have evaluated and validated this ‘total-life’ approach as part of a multi-year research project involving a team of industry-wide durability experts, including HBM Prenscia. Results of this new total-life method detailing our involvement in this FD&E total life project were discussed at the M200 session of the 2019 WCX: World Congress Experience on April 10th.

We also shared a presentation describing how this total-life method has been implemented in nCode, including descriptions of the required inputs for FE modeling, material properties, residual stresses, and applied loading. Contact us to learn more.




Editor's Note: This article was orignally published May 2019 and has been updated to contain updated reference material for WholeLife.