Engineered Rapid Assessment Method For Shock Resistance Of Propulsion Shafting

The various types of ships will be threatened in the shock environment, especially the ship equipments which are easily damaged. As the power equipment of ship, the propulsion shafting affects the ship stability and security directly. In order to achieve the rapid assessment for the shock resistance of propulsion shafting in the design stage, this paper studies the rapid assessment method for engineering research, and makes the method program by summarizing the advantages and disadvantages of generalization program. The limit loads of propulsion shafting will be determined by a lot of conditions based on the fast calculation method. Then the security of shafting will be judged by the comparison of shock load and limit load. The above program only makes the comparison, and the complicated calculation process is avoided. Therefore, the rapid assessment of shock resistance is achieved, which facilitates the engineering application.First, this paper checks the shock resistance of propulsion shafting in the surface fast ship with the generalized assessment method, and the rapid assessment program is determined based on the method features. Besides, the generalized assessment method does not consider the precession phenomenon of shafting stern. This paper studies the vacancy, and excludes its impact on the shock analysis.According to the program, the problems which are related to the rapid assessment of the shock resistance of propulsion shafting are determined. The first problem is the method for rapid calculation. To solve this problem, the beam is used to simplify the shafting, and the feasibility and stress relationship are finished by the numerical simulation. The result shows that the beam modeling process is not complicated, and solves quickly; the displacement responses of the two models are closer, and the stress has a certain proportion, which provides the basis for the rapid assessment.A lot of conditions for the propulsion shafting of different tonnage ships are studied based on the rapid calculation, and the threshold curves are finished according to the limit loads. The threshold curves are the demarcation of safe loads and dangerous loads, which can be used to judge the security of propulsion shafting.In order to assess the resistance of shafting in the environment of underwater long-range explosion, the hull structures are considered into the underwater shock wave, and the loads calculation method for the shafting are finished. The specific course of study experiences a process of shock wave-design spectrum speed-shock spectrum-calendar load, and the design spectrum speed expression is focused, which is verified based on the test date then. The shock load can be compared with the threshold curve directly, and the shock resistance of propulsion shafting can be assessed rapidly.Finally, in order to verify the threshold curve which is made based on interpolation method, the shock loads outside the fitting points are selected, and the shafting of different tonnage ships are calculated based on the loads. The result shows that the threshold curves have a higher precision, and the evaluation criteria are a bit more conservative.