EPSRC Reference: 
EP/K037161/1 
Title: 
Mid and HighFrequency Vibroacoustics of Builtup Structures  A Wave Approach 
Principal Investigator: 
Renno, Dr J 
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Department: 
Faculty of Engineering & the Environment 
Organisation: 
University of Southampton 
Scheme: 
EPSRC Fellowship 
Starts: 
01 October 2013 
Ends: 
30 June 2015 
Value (£): 
489,871

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Panel History: 

Summary on Grant Application Form 
Noise and vibration are important performance aspects in many mechanical systems. High noise and vibration levels can be detrimental to structures (e.g. causing damage) and to the human operators (e.g. causing fatigue or injury). Thus, it is important to be able to understand how structures vibrate and emit noise, i.e., their vibroacoustic behavior. Traditionally, engineers would try to describe the vibroacoustics using analytical methods. However, these are only possible for very simple structures. Structures that engineers confront in the aerospace, railway or maritime sectors are often made of composite panels that are connected together using complicated structural joints. The analysis of the vibroacoustics of such complex builtup structures cannot be performed analytically.
Over the years, researchers have developed numerical techniques to solve this problem. Elementbased methods (such as the finite element method) are welldeveloped and wellestablished methods with many commercial/inhouse codes that can be used. However, aerospace, railway and maritime structures are relatively large. For example, a typical railway car can be modelled using the finite element method up to 500 Hz. Above this frequency, the size of the finite element model becomes too large, impractical and the associated computational cost becomes prohibitive. However, the audio frequency range is 20 Hz20 kHz. At high frequency (above 10 kHz), the railway car can be modelled using energybased methods such as the statistical energy analysis method. Energybased statistical methods are valuable, but less wellestablished than elementbased methods. The railway car example points to a frequency gap, indeed a midfrequency gap, where neither elementbased nor energybased methods can be used.
I am proposing to use wave methods to bridge the midfrequency gap and to further strengthen energy methods. Waves provide a unifying, intuitive approach to vibroacoustics. The computational cost of a wave model is substantially small (especially when compared to a full finite element model), and the wave properties of structures can be obtained by post processing the finite element model of a small segment of an arbitrarily large structure.
Thus, the goal of this programme is to develop a wavebased toolbox for modelling the vibroacoustics complex builtup structures. Industrial examples from the aerospace, railway and maritime sectors will be used to demonstrate the efficiency and effectiveness of the developed methods.

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Organisation Website: 
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