Acoustics and Vibrations
The evolution of the production means towards a constant increase in performance is associated with increased operating speeds of the machines together with a weight reduction of their moving parts. As a natural effect of these two trends, vibrational problems in industry are increasingly widespread. Noise is a particularly important effect of vibrations, both from the point of view of the working conditions of the workers and the noise in products used by increasingly demanding users due to their increasing living standards. In this sense the European directives keep an increasingly restrictive trend for manufacturers of household appliances, automotive, aerospace,... parts, etc.
The difficulty for a correct diagnosis and troubleshooting of noise and vibration problems requires specialists with high levels of knowledge and experience. For this qualification it is necessary to use specialized techniques in simulation and experiment techniques.
The Acoustics and Vibration group of the Engineering Faculty of Mondragon University works on characterization and theoretical-experimental analysis of vibration and acoustic emissions, with the purpose to propose practical solutions that optimize the vibrational and acoustic behaviour of industrial products and processes. To this end it develops a knowledge generating and innovation activity (research) by means of generic projects and PhD thesis, which supports the accomplishment of application projects (transfer) for companies.
Research areas and transfer
The Acoustics and Vibration Group develops its activity in the following fields:
1. Identifying noise and vibration sources, and analysis of both structural and airborne transmission paths, of pieces and structures:
- Theoretical and experimental characterization of vibrational and acoustic behaviour.
- Temporal and spectral analysis.
- Experimental and operational modal analysis, ODS, ...
- Acoustic intensity maps.
2. Vibroacoustic Design:
- Characterization of materials (damping, insulation and absorption) by experimental measurements and simulation methods.
- Simulation of parts and structures to optimize their vibroacoustic behaviour: analysis of distribution of mass, stiffness and damping.
3. Sound Quality:
- Subjective analysis by means of jury tests (of original or edited sounds to assess the effect of design modifications).
- Objective analysis (calculation of metrics).
- Obtaining psychoacoustic models (by multiple linear regressions).
- Definition of product sound quality.
Below a sample of illustrative projects undertaken by the Acoustics and Vibrations group with public and private funding is shown:
- Project with IRIZAR to improve the acoustic comfort of the bus (Projects Abroad), (2006-2010).
- SANBUS: Sandwich structures for coach vibroacoustic comfort (Research), (2007-2010).
- PROMMTEAC: Project with MAIER on noise issues (Projects Abroad), (2009-2012).
- VIBROACÚSTICA: Working group with ORONA and IKERLAN to improve noise and vibration comfort in lifts (Projects Abroad and CENIT), (2004-2012).
- UNIONES: Optimizing vibroacoustic comfort in an elevator car by controlling the damping introduced by adhesive bonding (Universidad Empresa), (2008-2009).
- CARTUNE: Optimization of the dynamics of competition vehicles (INTEK), (2006-2008)
- NUDA: Numerical methods for the analysis of the dynamic behaviour of structures with high damping (Basic and Applied Research), (2005-2007).
- NOISELESS: Reduction of Noise Emission in Machine Tools, (project funded by the VPM of the EC), (2002-2005).
Among others, the following resources are available:
- For experimental measurements: Bruel & Kjaer Pulse system with a front-end of 34 channels, Ideas-Test with VXI Agilent front-end of 16 channels, spectral analyzer of 4 channels OROS OR254-II, DACTRON vibration servocontroller LASERusb model with two input channels, various electrodynamic shakers, various impact hammers, binaural head, reference acoustic source, several accelerometers and microphones, sound intensity probe, noise and vibration calibrators, Polytec vibration measurement system using laser interferometer, Kundt’s tube to measure sound absortion and transmission, system to measure damping, etc.
- Simulation software:
- CAD: SOLIDWORWS, SOLIDEDGE, UNIGRAPHICS.
- Structural calculations: ABAQUS, MSC PATRAN/NASTRAN.
- Experimental Modal Analysis: Test for I-DEAS.
- Vibroacoustic analysis: LMS Virtual.Lab.
- Sound intensity maps and sound power: Test for I-DEAS, dBFA32 from 01dB.
- TPA module and sound quality from PULSE.