PSI - Issue 68

Alen Marijančević et al. / Procedia Structural Integrity 68 (2025) 1203 – 1207 A. Marijancˇevic´ et al. / Structural Integrity Procedia 00 (2024) 000–000

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(a)

(b)

Fig. 2: Intermediate shaft: (a) Total lateral deformation, (b) Total bending moment.

required safety factor. Special attention in the analysis was given to the intermediate shaft with 410 mm diameter and multiradii transition towards the flange at the connection with the propeller shaft, similar to study described in Song et al. (2020). Simplified method to define permissible torsional vibratory stress in steady state and transient condition could be found in Han et al. (2015).

3. Results and discussion

Several analyses were performed in this study, including free vibration (modal) and forced steady state analysis. Fig. 3(a) shows the von Mises stress of intermediate shaft section near flange connection to propeller shaft loaded with torsional torque of 206161 Nm at rated speed 77 rpm. Earlier analysis showed that intermediate shaft is loaded with bending moment 80043 Nm. In Fig. 3(a) it can be seen the bending moment causes a minor influence on the state of von Mises stress.

4. Conclusions

Several analyses were performed in this study, including free vibration (modal) and forced steady state analysis. It can be seen that bending moment causes a minor influence on the state of von Mises stress at the shaft to flange transition with a multiradii design. Slow steaming mode at 70% of MCR power o ff ers exactly the same vibration regime compared to the MCR point.

Acknowledgements

This study has been supported by the Croatian Science Foundation under the project IP-2020-02-8568 and by the University of Rijeka under the project number uniri-iskusni-tehnic-23-112.