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Offre de thèse_From structure to dynamics in a model fibrous materials: vibroacoustic behavior of mineral wool

Saint-Gobain designs, manufactures and distributes materials and solutions which can be found everywhere in our living places and our daily life. They provide comfort, performance and safety while addressing the challenges of sustainable construction, resource efficiency and climate change.


Glass wool is a mat of entangled glass fibers held together by a dispersed polymer binder. A better understanding of structural dissipation mechanisms within the material is of high interest to try and improve acoustic performances of building elements such as, for example, floating floors, walls or ceilings.


As for other materials like polymer composites reinforced with fibers, biological tissues composed of collagen fibers or disordered fibrous material, many unknowns exist in the characterization and description of the micro- meso- and macrostructure of glass wool: fibers length and diameter distribution, spread of binder, fiber/fiber interaction including direct mechanical contact, with friction and possibly adhesion…


This PhD project draws on previous works carried out these last years within Saint-Gobain, to link microstructure of fibrous materials to their macroscopic acoustic behavior. Until now, this has been done assuming that the glass wool structure is motionless. The scope of the present project is to continue this work by taking into account the viscoelastic behavior of the material in the framework of Biot’s model.


Lab scale experiments will be performed on model fibrous samples in order to explore the influence of the relevant key parameters, mainly binder mechanics, individual fiber geometry and fiber arrangement in the wool. An innovative approach will be developed at SIMM, based on confocal microscopy. In addition to a precise 3D measurement of fiber morphology and position, the technique will also help validating assumptions on the nature of fiber-fiber contacts by using in situ deformation during volume imaging and modeling the measured displacement fields. These detailed structural results will be fed into mechanical models of the fibrous assemblies and compared with measurements of the macroscopic response. This part of the project will be carried out at UTC. First, the mechanical properties of the glass wool (Young’s modulus and loss factor) will be determined at several scales using a quasistatic dedicated test bench. Secondly, on the basis of previous works, numerical modeling of the fibrous network at the microscopic scale accounting for the network geometry, binder and fiber properties, effect of contact for large strain will be further developed.


This thesis proposition is part of an ongoing collaboration between Saint-Gobain Research, UTC and ESPCI. The workplace will be shared between the three entities.


Funding: CIFRE


Profile: Engineering student or Master 2, specialized in Acoustics, Mechanics or Materials Sciences, with interest in both experiments and numerical methods (FEM)


Contacts: Laboratoire Roberval, Université de technologie de Compiègne (UTC), FRE CNRS 2012, Centre de Recherches Royallieu, CS 60319 - 60203 COMPIEGNE cedex

- Nicolas Dauchez,


Laboratoire Sciences et Ingénierie de la Matière Molle (SIMM), ESPCI, 10 Rue Vauquelin 75005 Paris

- Etienne Barthel,


Saint-Gobain Research, 39 Quai Lucien Lefranc, 93303 Aubervilliers

- Sylvain Berger,

- Gary Jacqus,

- Alessandro Benedetto,

- Maria Malheiro Reymao,