FEM-based Vibrational Power Flow Analysis Of Structures Consisting Of Plates

Extensive vibration can cause fatigue damage of engineering structures, especially naval architectures, and result in malfunctions of mechanical machinery and onboard electronic devices, even induce severe noise level due to the structural vibration radiation. Flat, stiffened plate and box structures are common structural components of ships. Researching on their vibration behavior, especially understanding the characteristics of distribution and transmission path of their transvers vibrational energy is most important to control vibration and noise for some more complex structures consisting of them.From the view of energy, we use the power flow analysis to investigate the structural vibration. Thus, not only the vibrational energy can be calculated, but also the energy transmission path can be predicted. In this paper, the vibrational power flow characteristics are numerically predicted for common structures found in naval architectures, such as plates, stiffened plates, and boxes. The transmission path of vibration energy is studied by means of the structural intensity visualization techniques. And the structural vibration is analyzed by using power flow theory. The main research topics in the paper are: 1) Modelling structural vibration intensity, defining vibration evaluation indicators- power flow transmissibility, and developing structural vibration intensity visualization method. 2) Investigating the effects of the excitation frequency, the excitation amplitude, structural damping ratio and lumped damper to power flow; Analyzing the influence of the excitation frequency, the number of stiffeners, and the stiffener forms to the power flow of stiffened panels. And 3) studying the effects of the entrained water and structural stiffness influence to the power flow of the box structure, and further, analyzing the vibration power flow properties of a complex box structure and discussing vibration control results.The power flow properties and transmission path of several structures are analyzed by means of the structural intensity visualization. The analysis methodology and steps developed consist of a useful tool for practical applications of vibration and noise control.