Frequency Response Function of a Submarine Hull

In this research, simplified physical model of the submarine hull has been considered as acylindrical shell containing ring stiffeners. It identification is done in low frequency,so, the goal is to determine frequency response function is in frequencies of low than100 hz. For determination of it, mass matrix, stiffness matrix and damping matrix ofmodel should be extracted. The structure is modeled in ansys11 software, and ismeshed with triangular element. Displacement domain of each node is considered inradial and axial direction, number of structural elements and coordinates of nodes aretheoretically analyzed by matlab software based on finite element rotating shell.Three matrixes above are extracted, then the natural frequency is obtained and thendiagram of function is drawn in the low frequency range. The achievements of usingthis method are determination of response of propeller−shafting system of hull,coupling propeller−shafting system to hull, the optimization of resonance changer inlow frequencies due to reduction of transmission noise of propeller to submarine hullwith technique of genetic algorithm, description of the acoustic signature ofsubmarine due to submarine propeller excitation which is being investigated by thedepartment of mechanics and this method can be considered as one of the maritimetechnologies and implemented as plan applicable in marine industries.

Keywords:

Mass matrix , Stiffness matrix , damping matrix , Frequency response function