Acoustics and Vibration Modelling and Analysis
Acoustics and vibration have a physical causal link which Xi can help explore via numerical modelling and analysis. Over a decade ago Xi lead the way in developing fully-coupled structural dynamics-acoustic models of large scale energy converting devices such as wind and tidal turbines. These initial models were focused on the identification of noise sources and the development of mitigations techniques. Over the proceeding decade, the fully-coupled approach has been expanded to examine the performance of a range of products at all physical scales from microscale transducer optimisation to kilometre scale offshore HVDC cable installation and its effect on the marine environment.
At all scales the central modelling principle is consistent; the structural dynamics are modelled; the surface acceleration of the structure imparts an acceleration on the fluid in an acoustic domain (e.g. air, water, etc); and sound is generated. Meanwhile, the mass and motion of the fluid domain also imparts a load on the structure thereby affecting its dynamics response. The model is therefore fully-coupled, i.e. the structure effects the acoustic domain and the acoustic domain effects the structure.
While the central fully-coupled premise is consistent across all models, the physical scale of the acoustic domain does control the modelling method. At physical scales where the wave length is comparable to the size of the geometry, the acoustics can be modelled with a finite element analysis. However, when the physical scale is far greater that the wave length of sound, other methods must be used, or couple with an FEA, such as boundary element method, ray trace or diffusion acoustics. At the small scale, such as in the case of hearing aid or mobile phone microphones, thermal and viscous acoustic losses also become and should be considered. Other physics can also be coupled to these models such as electrostatics and fluid flow. Xi have the experience to help research and development teams develop and implement the best simulation approach to acoustic and vibration modelling and analysis.