LAUSR

This paper presents a novel method to control passively the interior noise of an enclosure such as car cabin by using the movement of the peak level and peak frequency according to the laminated angle of carbon fiber reinforced plastic composite plate. Recently, the use of carbon fiber reinforced plastic laminated plates in a car has been increased in order to reduce the weight of a car. For example, the metal plate roof has been replaced by the carbon fiber reinforced plastic plate roof for weight reduction of an electric vehicle. The characteristics of the interior noise inside of a car made of carbon fiber reinforced plastic plate roof can be changed according to the laminated angle of carbon fiber. In this paper, how this characteristic is changed was studied based on the effect of laminated angle of carbon fiber. In order to perform this study, a closed box with one flexible side wall and five acoustically rigid side walls was modelled as the interior compartment of a car. The flexible side wall of the closed box regards as the roof plate of a car. For the flexible side wall of the closed box, three carbon fiber reinforced plastic plates with different angle-ply (±θ) laminates each other were used. Therefore, three carbon fiber reinforced plastic plates with the fiber lamination angles of [−15/15/15/–15]s, [–30/30/30/–30]s, and [–75/75/75/–75]s were fabricated and used as the flexible side wall of the closed box. How the interior noise inside of the closed box was changed according to the laminated angle was studied by theoretical and numerical methods. For the validation of theoretical and numerical methods, the experimental work was performed. Finally, the carbon fiber reinforced plastic plate roof for a passenger car was numerically simulated, and the effect of the laminated angle on the interior noise was studied.