PSI - Issue 75

Per-Olof Danielsson et al. / Procedia Structural Integrity 75 (2025) 572–580 Per-Olof Danielsson et al. / Structural Integrity Procedia (2025)

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Fig. 3. Overview of the fatigue analysis process using physical measurements for load determination.

Furthermore, the integration of Internet of Things (IoT) and comprehensive customer usage data has refined load estimation methods, enabling more physics-based approaches to fatigue design. These advancements facilitate a transition away from conservative, incremental methodologies towards more precise and optimized structural designs. Moreover, recent investments in modern manufacturing equipment enable the production of structurally efficient solutions with lean manufacturing principles. Increased automation and integrated weld preparation enable the achievement of high-quality welds with reduced manual effort, enhancing overall manufacturing efficiency and quality. 3. Innovations in Fatigue Analysis, Design, and Production Engineering 3.1. Enhanced Fatigue Analysis Method (SFM ) To overcome limitations in traditional fatigue analysis, Volvo CE developed and verified the SFM approach [1-3], based on Linear Elastic Fracture Mechanics (LEFM) and currently applies to weld root configurations . Fatigue analysis of weld toes is excluded from this paper and will be addressed in future publications. The SFM approach improves fatigue life prediction accuracy and reduces analysis time and simplifies the CAD-modelling input for FE analysis. Pre-calculated geometry factors stored in a database streamline the calculation of stress intensity factors, making fatigue analyses more efficient for complex weldments. The number of load cycles for a crack to grow from an initial size to a size where the structure dis-integrates can be calculated by integrating Paris’ law . Features such as crack closure models and mean stress effects can be added to this model. See Table 1. for explanation of the variables used: (1) The SFM approach combines the limited need for high-resolution finite element modeling required by both the effective notch stress and fracture mechanics methods showing much higher accuracy compared to both nominal [4] and effective notch stress methods [5]. It leverages the unique properties of fracture mechanics by considering only stress components that contribute to crack growth. The SFM approach offers the accuracy of fracture mechanics methods but is easier to use and applicable to complex welded structures. Unlike the ENS method, the SFM approach accounts for varying crack-driving stress along the potential crack path, something the simpler nominal stress and ENS methods cannot address, see Fig. 3.