PSI - Issue 68

E. Ezgi Aytimur et al. / Procedia Structural Integrity 68 (2025) 540–546 E. Ezgi Aytimur / Structural Integrity Procedia 00 (2024) 000–000

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strains and the Johnson-Cook material model is preferred for larger strains and large impacts. On the other hand, comparison with experimental data is also important to assess the accuracy of the modelling results.

4. Conclusion

In this study, the e ff ects of strain rate dependence integrated into material models on the deformation and energy absorption of materials after single impact collision are investigated. A steel ball was impacted against the plate using Ansys LS-DYNA software to perform impact analysis according to one of the NHTSA regulations. According to the simulation results, the following results were observed: • The use of strain rate-dependent material models, such as the Johnson-Cook and Cowper-Symonds models, significantly improves the accuracy of crashworthiness simulations by capturing the complex material behavior under dynamic loading conditions. • The study shows that strain rate e ff ects have a noticeable impact on crashworthiness simulations. • It can be said that the simulation results are consistent with the findings of previous studies. • Results demonstrate the Johnson-Cook model’s superior performance in predicting deformation, stress distribution, deceleration, and restitution coe ffi cients compared to the simpler Elastic model. • While both strain rate-dependent models give similar results, the Johnson-Cook model gives more accurate results, but Cowper-Symonds may be preferred for its simplicity. • The choice of material model should be carefully considered, balancing between predictive accuracy, computational e ffi ciency, and model complexity, to meet specific application requirements. • Further validation through experimental data comparison is important to ensure the reliability and accuracy of crashworthiness simulations for optimizing vehicle design and enhancing occupant safety.

Acknowledgements

The author would like to thank Asst. Prof. Eser Yarar from Kocaeli University for his valuable time and support in this study.

References

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