A Stiffener Layout Design Method for Vibration Reduction in a Wide Frequency Band

Stiffened plates and shells are widely used in aerospace, marine, automotive, and other industries due to their high strength to weight ratio and ability to prevent buckling. In addition to these properties, stiffeners are also of great importance for vibration control. Natural frequencies can be tuned by the design of stiffeners to meet the requirements of dynamic integrity. Geometries, sizes, and layouts of stiffeners play a significant role in determining the natural frequencies of stiffened structures, among which the layout design of stiffeners has been identified as the most challenging task. In this paper, a stiffener layout design method is proposed to achieve vibration reduction in a wide frequency band. The principle of the method is to assign natural frequencies by adding stiffeners progressively according to the energy distribution of mode shapes. As a result, neighboring natural frequencies are manipulated in the opposite direction, whereupon a frequency band is opened for vibration suppression. The method is investigated in a squared plate. The gap between natural frequencies is increased during the process of iteration validating the proposed design method. The gap width of the designed stiffened plate can be enlarged by 410%.