Description: The design of an aircraft is a highly iterative process. During the conceptual design phase there is no time for developing detailed simulation models and decisions are typically made either by using low fidelity models or existing data and regression models. However, the decisions made during the conceptual design phase greatly affect the performance of the aircraft and the associated cost, and typically the majority of the cost is locked during very early stages of the design process. Usually the sound insulation requirements of a passenger cabin are met after the outer mold line of the aircraft and the design of the fuselage structure have been completed and this approach adds weight to the design. Ideally the structural-acoustic concerns should enter the design cycle early and be considered along with other main design disciplines. During the early design stages of an aircraft the interior noise performance of different fuselage configurations must be evaluated based on the following information: length, cross sectional stations as a function of longitudinal location, main interior arrangements, spacing and size of stiffeners and stringers, thickness and material properties of insulation blankets, thickness and material properties of the fuselage and of the trim panels, and the type of acoustic treatment placed in the interior. The acoustic performance expressed in terms of noise reduction comprises the metric for assessing the aircraft performance for interior noise considerations. The proposed project will develop an easy to use, physics based, computational capability that can provide fast an assessment for the interior noise of either conventional or novel aircraft during the early stages of the design process. It will also allow engaging information from multi-scale simulations for designing quiet composite materials with increased damping and reduced radiation efficiency characteristics.

Benefits: Interior noise concerns are present in civil aircraft design since the structural-acoustic performance is directly related with the perceived product quality and the occupant comfort. Currently, structural-acoustic concerns are typically addressed late in the design cycle when the structural configuration has been finalized. Therefore bringing structural acoustic simulations early in the design cycle will offer cost and weight savings. Thus, there is a great market potential for the outcome of this SBIR in the aircraft manufacturing industry. The proposed development fits well the business activities of the proposing firm in the area of computational structural-acoustics and in product design.

Structural-acoustic concerns are present in aircraft structures, launch vehicles, and spacecraft, since they are directly related with occupant comfort and noise induced vibration on payloads and electronic equipment. In all of these areas decisions made early in the design are critical for the performance and the cost of the system. Currently, structural-acoustic concerns are typically addressed late in the design cycle when the structural configuration has been finalized. Bringing structural acoustic simulations early in the design cycle will offer cost and weight savings. Therefore, the proposed developments will be useful to all NASA groups interested in reducing weight and cost when designing aircraft, launch vehicles, and spacecraft.