## 6 Conclusions  
This paper presents a case study of an electric propulsion shaft system, establishing a finite element model that includes an equivalent model of a high-elasticity coupling for the propulsion shaft system. The impact resistance performance is simulated using both the DDAM method and the time-history method. Through the analysis of the computational results, the following conclusions are drawn:  
(a) Simulation calculations of the impact resistance for a finite element model of a propulsion shafting system containing an equivalent model of a high-elasticity coupling using different computational methods indicate that the equivalent model is convenient for modeling and has a higher computational speed, which allows for rapid forecasting of the impact resistance characteristics of a propulsion shafting system containing a high-elasticity coupling.  
(b) Comparative analysis of the impact resistance simulation results for a ship's electric propulsion shafting system containing a high-elasticity coupling using the Dynamic Design Analysis Method (DDAM) and the time-history method demonstrates the accuracy of the established equivalent model of the high-elasticity coupling.  
(c) Comparison of the impact resistance calculation results between DDAM and the time-history method reveals that the maximum impact displacement calculated by DDAM is 22.47 mm, occurring at the driven end of the high-elasticity coupling, and the maximum impact stress is 252.67 MPa, occurring at the thrust bearing support point. The time-history method calculates a maximum impact displacement of 15.61 mm, also at the driven end of the high-elasticity coupling, while the maximum impact stress is 180.45 MPa, occurring at the thrust bearing support point. The impact response results from the DDAM method are relatively larger, and the calculations tend to be conservative.  
(d) Based on the impact resistance calculations for the propulsion shafting system using DDAM and the time-history method, the impact displacement of the high-elasticity coupling is less than its radial displacement compensation range (\(\pm\)24 mm); the impact stress of each shaft section is much lower than the allowable stress of the shaft section, which is 530 MPa. This indicates that the electric propulsion shafting system containing the high-elasticity coupling can safely operate under this impact load.  
(e) Through the application of diverse methodologies in the investigation of the impact resistance performance of electric propulsion shaft systems incorporating high-elastic couplings, this research has furnished both the empirical data and theoretical underpinnings for the future design selection and predictive modeling of impact resistance for a variety of shaft systems and high-elastic couplings with distinct structural configurations.  
Conceptualization, Methodology, Investigation, Writing--Original Draft, Writing--Review and Editing, Y.G.; Conceptualization, Methodology, Formal Analysis, Investigation, Writing--Original Draft, Z.M.; Resources, Supervision, Funding Acquisition, Validation, R.Z.; Conceptualization, Methodology, Formal Analysis, J.W.; Formal Analysis, Validation, Z.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China's Major Program (Project No.: 51839005): For the theory and technology for the control-oriented intelligent installation of large marine propulsion shafting, the funder is [PERSON].  
Not applicable.  
Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors declare no conflicts of interest.