Fatigue assessment of welded joints at sub-zero temperatures by means of stress averaging approach

The problem of typical stress-based fatigue assessment methods is that additional influencing factors like temperature effects do not directly influence the respective stress and can thus only be incorporated via modification factors. The stress averaging approach is expected to account for effects that influence the support around notches via the micro-structural support length ρ*. This study thus investigates the applicability of the stress averaging approach for welded joints in engineering structures exposed to sub-zero temperatures. For this purpose, fatigue test results of welded joints in the temperature range of 20°C down to −50°C are assessed. It is shown that it is possible to assess data for different temperature with the same reference fatigue curve while maintaining a small scatter without the need for modification factors.