Advanced Modeling of Aircraft Interior Noise using the Hybrid FE-SEA method

Noise transmission paths in an aircraft include, in many cases, both components with a few modes and others with a high modal density. The components with few modes display a long wavelength behavior and are usually modeled using the Finite Element Method (FEM). On the other hand, components with many modes show a short wavelength behavior and suit the application of the Statistical Energy Analysis (SEA). An example of this kind of transmission path is given by the vibration transmission from the fuselage to the floor panels through the floor beams. The fuselage and the floor panels possess a high modal density while the floor beams are considerably stiff and display a small number of modes. The prediction of the vibro-acoustic response of such systems is commonly called the “mid frequency problem” and, until recently, was difficult to be handled with traditional modeling approaches. A Hybrid method that rigorously couples SEA and FEM has been recently proposed. In this work, different applications of the Hybrid FE-SEA method to aircraft interior problems are investigated and validated against experimental results. It is seen that the Hybrid FE-SEA method can considerably improve the predictions of “mid frequency problems”. It is also demonstrated that the method can be successfully used to improve SEA models by including some details to the model that affect the vibro-acoustic performance of the system.