A numerical model of a cylinder of marine steam turbine was established for analyzing its reliability under the impact of fractured blades. In this model, the initial speed, mass, yield strength, modulus of elasticity of the fractured blades, as well as the elastic modulus, yield strength and ultimate strength of the cylinder material were taken as random variables. A certain number of samples were acquired using Monte Carlo method. The distribution of random variables was obtained via curve-fitting using a few samples among them. Then, 50 groups of initial values of random variables were obtained using the program for generating random variables, and the process of penetration of the cylinder was simulated with this model. The maximum equivalent stress of the cylinder was obtained. Adopting the ultimate strength criteria and W-testing, the maximum equivalent stress of the cylinder was validated to obey the normal distribution, and the destructive probability of the cylinder was obtained. A reliability analyi

Underwater mechanical noise is one of the main noise sources of submarines. In this paper, the transfer paths of radiation noises of mechanical equipments of the submarines are analyzed, and the procedure from shell vibration to radiation noise prediction is studied theoretically and experimentally. Distribution of vibration acceleration of the inner and outer shells is measured by model testing. The mean-square vibration velocity of the inner and outer shells is computed. With sub-band radiation efficiency formula of stiffened cylindrical shell, the values of radiation sound pressure are predicted using the mean-square vibration velocities of the inner-and-outer shells. The results are compared with the experimental data. It shows that the computation and experimental results are in good agreement. It is concluded that only the inner-shell vibration signal is necessary for prediction of radiation noise of the double-layer shell structure. Therefore, the feasibility of radiation noise prediction through the shell structural vibration is demonstrated.