Optimisation Potentials of Laminated Composites Using Semi-analytical Vibro-Acoustic Models

Light and stiff composites such as fibre-reinforced plastics are sensitive to propagate structure borne sound but simultaneously can be manipulated to adjust the material behaviour. Furthermore, stiffness and damping of such composites have contradictory material properties in relation to the fibre orientation. Composite designs are normally analysed based on FEA that require special modelling efforts. However, a multi-dimensional optimisation approach of laminates with numerous layers consisting of different materials and different orientations requires very fast numerical solutions for numerous repetitions. Here, the FEA is extended by a strain energy-based modal with a damping approach for the layerwise accumulation of the anisotropic damping. The radiated sound power is determined by a velocity-based approach directly on steady state structural simulations avoiding a complex multi-physical modelling. Moreover, the frequency dependent radiation is consolidated to a single scalar optimisation objective using a fast and efficient semi-analytic approach. This efficient simulation methodology is applied to design a vibro-acoustic composite oil pan. The achieved results show the optimisation potentials of thermoplastic composites with various fibre and matrix materials in comparison to a steel as reference case.