PSI - Issue 68

Emanuele Vincenzo Arcieri et al. / Procedia Structural Integrity 68 (2025) 1324–1328 E.V. Arcieri et al. / Structural Integrity Procedia 00 (2025) 000–000

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The relationship between the impact speed and the dent depth after impact appears to follow a second-degree polynomial equation across the entire range of impact speeds investigated, with an obtained coefficient of determination R 2 close to 1 (Fig. 2a). If results for impact speeds below 120 m/s are excluded, the trendline equation changes slightly, and the coefficient of determination increases marginally (Fig. 2b). This minor variation can likely be attributed to numerical approximations, such as rounding and discretization errors, that have a more pronounced effect at lower impact speeds, when post-impact dent depths are smaller. However, the material model used for the hourglass specimen is elastic perfectly plastic and does not account for potential material removal, which may occur at high impact speeds. Material plasticity could be modelled with alternative approaches based on stress-strain curves obtained from experimental testing, such as power law, bilinear hardening and piecewise linear. In Fig. 2c, the displacement at the end of the simulation at the minimum cross section of the specimen is shown for a specific impact case. The dent depth was determined as the maximum displacement observed in this cross section. 3. Conclusions and future studies This study analyzed the geometry of the dent created by the normal impact of a ball with an hourglass-shaped aluminum alloy specimen using the finite element method. A second-degree relationship was observed between impact speed and dent depth. However, the material model adopted for the hourglass specimen cannot simulate potential material removal, that may occur at high impact speeds. This limitation may influence prediction accuracy at high speeds, as material loss could provide a different dent geometry and consequently fatigue life. The presented results contribute to the understanding of impact damage mechanics and provide a basis for developing predictive models to estimate the geometry of the impact dent and the resulting stress concentrations and residual stresses. These factors are essential for accurately estimating the fatigue life of components subjected to impact damage. Future studies should use more complex material models to improve the accuracy of damage prediction, particularly at high impact speeds. In addition, to develop a robust predictive model for dent geometry based on impact parameters, i.e. to find the relationship between the impact parameters and the coefficients of the impact speed vs. dent depth trendline equation, a variety of impact scenarios involving different materials of both impacting and impacted objects and geometries should be investigated. References ABAQUS, ABAQUS Documentation, Dassault Systèmes, Providence, RI, USA, 2017. Arcieri, E.V., Baragetti, S., 2024. 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