PhD Position: Acoustic Black Holes for Silent SYStems (ABHSSYS), Marie Curie

Context

Siemens Industry Software NV is hiring a doctoral candidate within the Marie Skłodowska Curie Actions (MSCA) project Acoustic Black Holes for Silent SYStems (ABHSSYS), funded by the European Commission’s Horizon Europe programme under grant agreement number 101227712.

ABHSSYS aims at delivering efficient noise and vibration reduction solutions without added mass, by using the so-called acoustic black hole effect. The network will train 11 doctoral candidates as scientists and engineers by means of PhD research tracks within an international and interdisciplinary consortium consisting of top European universities and companies.

The doctoral candidate will join the research team of the Test Division at Siemens in Leuven, Belgium, and will be enrolled in a dual PhD programme at INSA Lyon and Le Mans University. Part of the research will be done via secondments to other institutions within the consortium and in cooperation with the other doctoral candidates. Regular workshops and trainings will be hosted by the different partners.

PhD Research Topic

Weight reduction is crucial for limiting the carbon footprint of automotive, aeronautical and aerospace vehicles. However, current noise and vibration mitigation solutions heavily rely on adding porous materials and visco-elastic layers to such structures. Acoustic black holes provide an appealing alternative, as they rely on redirecting and concentrating energy in small areas of the structure, thus requiring less damping material.

Research on acoustic black holes has evolved from a theoretical concept in the 1980s1 to a mature field2 with dedicated sessions at international conferences. Despite its great potential, exploiting the acoustic black hole effect in real-world applications requires radically different design paradigms, departing from conventional solutions. Therefore, industrial applications and demonstrators remain scarce, but are now within reach.

The primary goal of the PhD is to evaluate the efficiency and robustness of the acoustic black hole effect when implemented on complex structures. In order to achieve this, the research is structured into the following phases:

Phase 1

• The first step is to review existing models of multi-layer structures3,4 and implement a computationally efficient framework for spatially-varying media. A sensitivity study will then be carried out to evaluate the impact of variations in the design parameters on the performance of 1D1 and 2D5 acoustic black holes.

Phase 2

• The second step will consist in developing a model-based experimental protocol for the retrieval of property gradients and for the spatial localisation of energy dissipation. Full-field methods such as laser vibrometry5, digital image correlation7 or thermal imaging6 will be considered, in conjunction with wavenumber recovery8. The parameter identification will be formulated as a statistical inverse problem using a Bayesian framework9, enabling a robust quantification of energy reduction in acoustic black holes embedded in complex structures

Phase 3

• The third step will focus on demonstrating the modelling and experimental protocols on real structures of aerospatial or automotive industrial relevance.