The Research On Vibration And Sound Radiation From Single And Double Cylindrical Shells Under Multi Forces

Reinforced single and double cylindrical shells are common structures in projects. This passage utilizes cylindrical shells to simulate ship cabins and studies vibration and noise related issues of them. The forces generated by the internal machinery and equipments inspire the internal cylindrical shell mainly through the transfer of bases, floating rafts and other structures. The contact between these structures and the shell can not be simply simulated by a single point. It is usually in the form of lines or faces. Therefore, in order to better utilize the cylindrical shell to simulate the real structure, this paper will focus on the vibration and sound radiation of reinforced single and double cylindrical shells under multi forces. There are two transmission paths between the inner and outer shells of double cylindrical shell, the path of the connection structure and the path of the flow field. To understand the influences of vibration and acoustic radiation caused by different paths helps in dealing with more complex problems.The Flügge equation of thin shell is applied to describe shell motion. The effects of stiffeners are treated as reverse forces and moments on the cylindrical shells, then the coupled vibration equation is solved. It assumes that the cylindrical shell meets the simply supported boundary condition, the shell displacements in three directions are expressed in the double-series form along the longitudinal and circumferential modal expansion. With the displacement and stress continuity conditions, the dynamic reaction forces of the ring ribs, longitudinal ribs and annular plates are represented by the displacements of the shell. Then the dynamic reaction forces are substituted into the vibration equation. Theoretical results of radial quadratic velocity, radiated power and radiation efficiency are presented. This paper discusses the transfer characteristics of double cylindrical shell, the vibration and sound radiation of cylindrical shell under excitation of the radial, tangential and axial single-point forces and axial and circumferential multi-point, linear and area forces. Some significant conclusions have been gained.