Your Location Within Site:
Acoustically efficient buildings
The problem
There is increasing concern in both New Zealand and overseas about the inadequacy of sound insulation in buildings and its implications for the occupants health and well-being in the face of the many sources of sound pollution.
Elastic meta-material sample consisting of multiple silicone rubber-coated steel balls embedded in a polymer matrix. Each coated ball acts as a local resonator. This sample was used for acoustic transmission measurements in an impedance tube.
Acoustic transmission through walls and ceilings at frequencies in the lower range of human hearing (approximately 100 Hz to 1 kHz) presents particular problems. That is because this is the range at which irritating acoustic intrusion frequently occurs (e.g. the bass beat from music systems) but where it is most difficult and expensive to achieve effective isolation using conventional building solutions.
IRL research
IRL is applying recent discoveries about the physics of wave propagation in meta-materials to the development of acoustic insulation systems that have much higher performance for a certain thickness and weight. We are exploiting the unique dynamic properties of meta-materials to create band gaps, that is, frequency bands in which sound wave transmission is attenuated exponentially.
Computational model of an early resonant slab used in the development of acoustic transmission simulations. This finite element model had approximately 160,000 degrees of freedom.
The key to our novel sound shielding approach is the engineering of low-frequency acoustic band gaps in panels using resonant internal structures whose design is based on meta-material physics.
This goal is being pursued through two parallel research tracks. The first is developing the modelling methods and test techniques needed to support the design of resonant band gap structures. The second is focusing on generating new knowledge, designs and technology relating to the sound shielding panels and their assembly into systems. The latter involves a close collaboration with our building industry partners, and in the future may involve other industry sectors.
The outcome of the research project will consist of novel building systems providing superior sound insulation, and methodologies for their systematic rather than empirical design. Among the other potential benefits is the application of this technology in other sectors, such as the appliance, marine and aerospace industries.
Industrial partners
Building Research Association of New Zealand (BRANZ) and Fletcher Building Ltd.
Scientific collaborators
Acoustics Research Centre, University of Auckland
Mr. Andrew Hall, PhD candidate, University of Auckland