Logo - La Salle   Oriol Guasch i Fortuny
Department of Engineering, La Salle, Ramon Llull University
Oriol Guasch
Research Areas

Graph theory applied to Statistical Energy Analysis
Statistical Energy Analysis (SEA) is widely used to simulate the vibroacoustic behaviour of structures in the mid-high frequency range. Once build the SEA model of a physical system many questions of interest for the noise control engineer can be posed. Which are the most dominant energy transmission paths from the source subsystems to the target ones? Which loss factors should be modified to reduce the energy received at a set of targets? How many paths of a given order do exist between any pair of subsystems in the SEA model? These questions and many others can be answered by setting them in the general framework of graph theory. Exploring and implementing the possibilities of applying graph theory to SEA is one of our main research topics.

Computational acoustics and aeroacoustics
Nowadays, the finite element method (FEM) has become central to address complex problems in many areas of physics. However, it is well known that the Galerkin approach to FEM suffers from many numerical drawbacks. To overcome them use can be made of stabilized finite element formulations. In particular, we apply sudgrid scale stabilized finite elements to solve various problems in acoustics and aeroacoustics. Recently, we have focused on articulatory speech synthesis and we aim at synthesizing vowels and syllables using finite elements.

Transmission path analysis using direct transfer functions
Transmission path analysis (TPA) allows factorising the response of a system dof (degree of freedom) in terms of the forces entering the system. However, if one has no means of controlling and/or measuring them, it may be more appealing to decompose the dof response in terms of other dofs responses (e.g., noise at the interior of a car cabin in terms of the panel vibrations). The problem is that transfer functions between dofs with blocked conditions are needed to do so, which can hardly be imposed in practice. However, it is possible to obtain these transfer functions (direct transfer functions) from the easily measurable transfer functions among responses that require no blocking conditions (global transfer functions), by appropriate mathematical manipulations. Our research focuses on the development of the direct transfer functions approach to TPA.

Ultrasound transducers to generate audible sound
Ultrasounds have many amazing and useful applications. One could take benefit of the fact that their propagation in air is strongly driven by non-linearity to generate audible sound with surprising properties, namely a very high directivity and constant intensity through the beam, until shock wave formation takes place (parametric arrays). One of the problems associated with parametric arrays is high power consumption. We investigate the use of new magneto-electro-elastic materials to build low power consumption ultrasound transducers that can be used in small mobile devices.