Sound waves and angular orientation in fibrous materials

International audienceAngular orientation is a state of fibers which can be intentionally changed to modify the properties of the corresponding material. Here, the angular orientation tensor of a fibrous material is identified from scanning electron microscope images, in order to construct a model of the microgeometry, in which the partial differential equations governing the physics at the upper scale can be solved. Permeability and impedance tube measurements show that the corresponding model is a good candidate to simulate the transport properties of fibrous materials. It is also shown that the transport properties of the samples are highly affected and tunable through the angular orientation of the fibers. The proposed numerical approach can be applied to evaluate the effective transport and sound absorbing properties of general fibrous materials just from the geometrical information embodied in the microstructural parameters of single fibers, the fibers orientation distribution and the bulk porosity