Nonlinear Dynamic Response Characterization of hemispherical shell under External Pressure: Innovative Vibration-Based Buckling Prediction Methodology

In this paper, a new method for predicting hemispherical shell buckling under external pressure is presented. Due to the suddenness of collapse under external pressure and uncertainty in buckling calculation in the shells with non-zero Gaussian curvature, this method can be used for health monitoring of deep submarines. In this article, the effect of external pressure on the natural frequency of the system was initially investigated, and it was shown that the natural frequency decreases under the impact of external pressure. In various examples, it has been shown that the value of the natural frequency under the effect of external pressure reaches zero between 60% and 80% of the value of the linear buckling pressure. Due to the error in linear buckling analysis of the hemispherical shell, explicit dynamic analysis has also been used. Eventually, it is shown that the buckling pressure can be predicted when the external pressure is about 90% of the collapse pressure. The findings of this paper show that by evaluating hull vibrations, it is possible to practically predict the buckling of deep-sea submarines before the submarine collapses.