Study of vibration propagation in periodic rib-stiffened plates using advanced statistical energy analysis

Abstract

Statistical energy analysis (SEA) is widely used in predicting dynamic response of complex coupled systems. This paper studies the bending wave propagation in periodic rib-stiffened plates in the framework of SEA. Effect of frequency band gap property of the rib-stiffened plate and wave filtering characteristics of the stiffened ribs on the prediction results of SEA is analyzed by using the wave approach and Bloch theory. It is found that due to the fact that classic SEA ignores an energy “tunneling mechanism” between subsystems that are not physically connected, large error up to almost 40 dB is generated in the subsystems of the plate compared with the results calculated from the finite element method. This tunneling mechanism mainly results from the wave filtering effects caused by the periodic arrangement of the ribs and it plays a significant role on the subsystem response at high frequencies. However, this is not incorporated in the modelling of classic SEA thus large errors can occur. To solve this problem, an advanced statistical energy analysis (ASEA) is used to consider the transition, transmission and transport of energy between unconnected subsystems. ASEA divides the energy of each subsystem into two parts: available energy which is the modal energy that could transmit into connected subsystems, and unavailable energy that dissipates within the subsystem; therefore the energy cannot propagate further away. Then the ray tracing algorithm is used to track the power flow across subsystems. By using ASEA, the accuracy of the prediction results can be greatly improved so that the error is reduced to less than 5 dB in most frequency bands. An experimental set-up is also designed to support the plate by simulating the simply-supported boundary conditions along the edges. The test results agree well with the finite element method, and it is sufficient to validate the theoretical models.