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Lightweight structures and designs have been widely used in a number of engineered structures due to ecological and environmental aspects. Nonetheless, lightweight structures typically experience a reduced noise and vibration reduction performance as a consequence of their increased stiffness-to-mass-ratio. To enhance it, novel low mass and compact countermeasures are often sought to address the challenges of achieving not only a good Noise, Vibrations and Harshness (NVH) reduction performance but also maintaining a lightweight design. Recently, locally resonant metamaterials have emerged and shown potential as a lightweight noise and vibration solution with a superior performance in tunable frequency ranges, known as stop bands i.e. frequency regions where free wave propagation is not allowed. These can be achieved by assembling resonant elements that are tuned to the targeted frequency range onto a host structure.

In passenger aircraft the most important noise control treatment is the primary insulation attached to the fuselage. Next to its acoustic properties the primary insulation main purpose is the thermal insulation and the minimization of condensed water. In general it consists of fibrous materials like glass wool wrapped in a thin foil. Due to stringent flame, smoke and toxicity requirements the amount of available materials is limited. Furthermore the amount of material installed in aircraft per year is much smaller compared to needs in the automotive industry. Therefore the best lay-up of the available materials is needed in terms of acoustics. This paper presents a tool for numerical optimization of the sound insulation package. To find an improved insulation the simulation tool is used in interaction with a measurement database. The databank is constructed from aircraft grade materials such as fibrous materials, foams, resistive screens and impervious heavy layers.