On Wednesday the 28th November, Peter Risby Andersen successfully defended his PhD thesis " Modelling of acoustic viscothermal losses using the Boundary Element Method: From method to optimization".
The PhD investigates the study of existing literature regarding the behaviour of acoustic and mechanical waves with losses in the micro-scale and the coupling of mechanical and acoustic domains. Systematic testing and development of numerical simulation and analysis tools that can model the behavior of the aforementioned small coupled devices with losses. This includes numerical methods based on the Finite Element Method (FEM), the Boundary Element Method (BEM) and a combination of them. Measurement of both simplified test setups and partial assemblies in order to verify and support numerical results. Optimization of acoustical-mechanical systems in order to achieve specific performance objectives in terms of acoustical and mechanical transmission, or absorption of sound waves. Both topology and shape optimization methods will be utilized. The new numerical tools and the acquired knowledge will lead to the study of state-of the art techniques and their applicability to the class of devices and design problems at hand. Examples of subjects include acoustic/structural metamaterials, transducer impedance matching and narrow tubes designed as filters.
The work which was presented in the form of a collection of papers, consisted of five papers, three being published journal papers, one conference publication and one submitted journal publication. The committee found the thesis timely and appropriate and the area not overcrowded with results and the presentation clear and didactic. The shape optimization proposed in Paper E, for which the viscothermal losses are critical, appears to be the first of its kind and in terms of scope, novelty and quality, the committee found the thesis entirely sufficient for a PhD thesis. The questions and discussion afterwards was active and stimulating, proving scientific maturity. Peter answered all questions, including the difficult ones fluently and indicated that he knows the limitation of his work and included suggestions for further work in the field.
Supervisor: Associate Professor Vicente Cutanda Henríquez
Examiners: Prof. Martin Berggren (Umeå University, Sweden)
Prof. Jean-Philippe Groby (Le Mans Université, France)
Assoc. Prof. Jonas Bronskog(DTU Elektro)
Chairperson: Associate Professor Cheol-Ho Jeong
Congratulations to Peter who continues as a post-doc. at DTU.
