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Acoustic engineering and management

Under these themes we explore the effect of noise from traffic on the levels of tranquillity in urban and rural environments.  Our team also have a strong interest in the sustainability of proposed solutions such as noise reducing barriers. The team make use of the acoustics laboratory for industry acoustic testing.

Two year knowledge transfer partnership (KTP) with Incommunities

The University of Bradford collaborated with Incommunities ltd on a two year funded project.

incommunities logo

Incommunities ltd, the largest Social Landlord in Bradford with 22,500 properties provides affordable, high quality homes in and around the Bradford area. The collaborative project, which was awarded a grant of over £120,000, was to support and sustain Incommunities’ positive, community led work.

 

The Knowledge Transfer Partnership (KTP) project titled: “Bespoke decision supply chain engagement, customer satisfaction and deliver sectorial customer change” provided tools and techniques at operational, middle management and senior management level to allow Incommunities, a social landlord, to make optimal long term decisions in meeting sustainable affordable housing needs.

With the climate of the economic world ever-changing in our modern society, it is important to have a decision support system that will allow Incommunities cost savings and reduce waste, water use, resources and emissions, but also deliver customer satisfaction, quality of life and organisational cultural change long term.

Mapping traffic noise

photograph of a motorway hangover

Research at the University of Bradford using novel boundary element methods has resulted in more accurate and efficient predictions of the noise created by roads and railways and of how sound spreads from the transport corridor, enabling more effective design and positioning of noise barriers and earth banks. Bradford researchers refined two areas of modelling applied to noise prediction, which helped to ensure that two new models 'NORD2000 and HARMONOISE' were able to provide more accurate results.

 

 

NORD 2000 was commissioned by the Nordic Council of Ministries and is used by Scandinavian national and local governments, to predict noise from roads and railways. It is mandatory to use Nord2000 in Denmark for strategic noise mapping. The model is also used by the Federal Department of Health in Canada.

Both models were incorporated into six new software packages used around the world to map noise and design noise reduction strategies and barriers, for road, rail, wind turbines and industry. The software packages – Predictor-LIMA, CadnaA, ExSound2000, SPL2000, SoundPlan and WindPRO – are used in over 40 countries, including most European countries, Brazil, Australia, Canada, Hong Kong, South Korea, Chile, and Taiwan.

Reducing waste and keeping the noise down

A sound-proofing material made almost entirely from recycled industrial waste has been developed by researchers at the University of Bradford.

Designed to dampen the effects of vibration as well as absorb sound, the material was demonstrated to be up to 50 per cent more effective than other materials on the market - despite being around three times as thin.

The University of Bradford set up a spin out company, called Acoutech, to commercialise the technology used to produce the material.

This technology was licensed to Armacell, a global company specialising in insulation products, which began to produce sound insulation products under the brand name ArmaSound. These have been used throughout the world in sound-proofed linings for vehicles and industrial-scale machinery.  The company is now able to use up to 95 per cent of its own waste materials to produce ArmaSound products.

image of an armacell soundproofing sheet

A real breakthrough for the technology came when it was approved for use in large-scale pipework projects. This led to the development of a compact insulation system that is now used widely to reduce the noise from large pipes at facilities such as petrochemical plants and offshore oil platforms.

In 2012 Armacell were awarded a contract to supply ArmaSound to the Gorgon Gas Project, a $45 billion natural gas facility to be constructed off the coast of Western Australia. This is the largest facility of its kind ever constructed and will use ArmaSound insulation in around 200km of pipe-work.

The technology developed at the University of Bradford has had a huge impact on large industries worldwide which need to control noise pollution. Not only has it been effective in reducing noise pollution, it has also created an environmental benefit, through using recycled materials that would otherwise go straight into landfill.

Through Armacell, the technology has created a significant economic benefit as well, creating over 20 jobs and enabling the company to achieve significant growth each year.

ArmaSound - high performance low cost acoustic absorber

Armafoam Sound developed at the University of Bradford is a high performance low cost acoustic absorber that is designed for demanding applications.

Through its structure, formulation and composition this material can offer around twice the acoustic energy absorption in a given thickness when compared with traditional materials. This allows designers and specifiers to reduce the space that they consume and to reduce the noise that users experience.

Armafoam Sound is the result of 4 years of research into poro-elastic materials that exhibit potential acoustic absorption capabilities. By modelling and optimising the material’s micro-structure, this product is designed to have very high levels of absorption across the frequency range.

Armafoam Sound can also be specially designed to meet the specific needs of the customer by being designed to focus its absorption at particular problem frequencies. This allows for a greater enhancement of the products noise control capabilities.

Most forms of noise will contain contributions from both air-borne and structure-borne sound. Although measures can be taken to limit structure-borne components, such as by isolation and damping, air-borne sound can be treated with the use of absorbing materials. Armafoam Sound has an extremely high absorption performance per unit thickness, offering a solution for the most demanding applications.

ArmaSound – a recycled multifunctional product:

  • Recycled sustainable material developed in partnership between the University of Bradford and Armacell.
  • Manufactured from post production foam scrap (Extruded NBR/EPDM Elastomeric thermal insulation)
  • Product offers very high levels of acoustic absorption. In addition the product offers:
    • Improved fire performance
    • Good chemical resistance
    • Combined thermal and acoustic properties
    • Mechanical stability and durability
    • Flexibility and ease of application
    • Resistance to fluid ingress - Hydrophobic properties
    • Resistance to microbial growth
  • Low manufacturing and raw material costs allow for the product to be competitive in the market

Ashford's Integrated Alternatives

The Ashford's Integrated Alternatives (AIA) project aims to explore the extent to which more integrated urban utility service provision, can contribute to enhancing the adaptive capacity of different service sectors and thereby improve the sustainability of urban development.

This will be achieved by researching issues of scale, integration and delivery, in order to reduce resource usage, limit damaging emissions, manage innovation and improve the quality of life for the inhabitants of study area, Ashford, Kent. The Bradford component of work focuses on how the public are engaged (or not), in processes of water and energy management.

Partners:

  • EPSRC
  • University of Exeter
  • Imperial College London
  • Cranfield University
  • University of Surrey
  • Ashford's Future
  • ARUP Group Ltd
  • Atkins
  • Bioregional Development Group
  • Chartered Institute of Water and Environmental Management
  • Environment Agency
  • IPM-Net
  • London Borough of Southwark
  • Ofgem
  • Waterwise

Holistic and sustainable abatement of noise by optimized combinations of natural and artificial means (HOSSANA)

Current city layouts and plans are the results of many factors but acoustic comfort is rarely one of them. The conventional approaches to noise reduction in urban areas include visually-intrusive barriers, which also contribute to severance, pervious pavements, double-glazing and traffic calming. In rural areas, conventional methods include noise barriers and cuttings.

The thrust of this EU FP7 funded research is that there are many areas and surfaces near transport corridors that could be exploited and optimized for acoustical purposes. These include verges, embankments, cycle tracks, walk-ways, building facades, balconies, roofs, car parking areas, parks and open spaces.

Building facades can be designed to be acoustically beneficial as well as decorative and new street furniture can be designed to be acoustically functional. Although parks and open spaces are used to provide a pleasant breathing space their ability to be acoustically restorative could be significantly improved through design. 

Sonic characterisation of water surface waves, turbulence, mixing and bed friction

This EPSRC funded project was a collaboration between University of Bradford, University of Cardiff and The Open University.

The goal of the project was to develop low cost non-invasive instrumentation for the monitoring of shallow water flows.

The University of Bradford developed a new ultrasonic technology for characterising the dynamic surface shape of the air-water interface, and has a patent on the design.

The team has also derived several important relationships between the hydraulic boundary conditions and the statistical moments of the water surface fluctuations, which allow for these conditions to be quantified based solely on the acoustically measured water surface shape.

Particle Image Velocimetry (PIV) is being used to provide enhanced understanding of the relationship between the water surface waves and the underlying flow structure, in order to establish further links between the surface's acoustic response and the hydraulic boundary conditions.

The success of the project provided a revolutionary piece of equipment that allows water industries to accurately monitor the conditions of their fluids and flow conduits, in a totally non-invasive low maintenance and cost-effective manner. 

Tranquillity and soundscapes in urban open spaces

Tranquil environments have been related to stress reduction, well being and recovery from illness. It is therefore important to determine factors that contribute to tranquillity and positive soundscapes in order to design and improve urban spaces that can benefit the living conditions of the citizen.

Research into factors that affect perceived tranquillity carried out by Professor Greg Watts employed a number of techniques including laboratory studies under controlled conditions, jury experiments in real environments and questionnaire surveys.

A predictive model TRAPT (Tranquillity Rating Prediction Tool) has been developed, which enables perceived tranquillity to be predicted in a range of environments, based essentially on man-made noise levels and the natural and contextual components of the visual scene.

The tool has recently been validated by conducting interviews with visitors in seven green spaces in the Bradford metropolitan area. In all these areas the major source of noise was from road traffic. Such a tool will be of use in designing and improving green spaces and maximising the benefits of such visits to our open spaces.

Working with SCANLab at the University of Sheffield has enabled the biological underpinning of this work is being explored. Using fMRI (functional magnetic resonance imaging) it has been possible for the first time to investigate how the human brain responds to tranquil and non-tranquil environments. Experiments are planned using a wider range of stimuli and experimental subjects, which will further improve the tranquillity prediction model.

Elucidation of the factors and mechanisms underlying subjective tranquillity will be a major achievement and produce significant new knowledge with respect to key environmental factors and architectural / planning interventions that affect personal tranquil state.

The project will provide insights into how to design tranquil spaces for the general public and restorative environments of relevance to recovery from stress and illness.

Quieting the Environment for a Sustainable Surface Transport (QUIESST)

QUIESST was a three year project funded by the EU. It wad a multi-disciplinary venture undertaken by 13 EU partners from 8 countries.

Within the project, specialist members of our Centre were been tasked with assessing the sustainability of Noise Reducing Devices (NRDs). These devices are designed to control noise from surface transport (both road and rail) and include noise barriers and absorbative claddings.

For the purpose of this research sustainability was defines as: 'the optimal consideration of technical, environmental, economic and social factors during the design, construction, maintenance and repair, and removal/demolition stages of NRD projects.

The research was focused on designing a sustainability assessment framework with appropriate methods and tools that can effectively be utilised to assess the sustainability of noise reducing devices. The framework presents results in a clear and practical manner for all stakeholders interested in using it; including procurement agencies, manufacturers and consultants.

Future Skills Curriculum Development Framework

The development of the built environment brings challenges and significant responsibilities; not least protecting the environment. Therefore, the need to adopt effective, long-term sustainable development strategies starts with the integration of academic and practitioner education that can be translated into the curricula. 

The Higher Education Academy, Centre for Education in the Built Environment (CEBE) funded research to evaluate a flexible framework to support and inform built environment curricula needs, including sustainability, sustainable communities, carbon criticality, and modern construction methods. 

The research explored current industry practices, map local and regional needs, identify good practice in curriculum development, devise a future skills curriculum framework, and integrate these into undergraduate engineering curricula, with a specific focus on how sustainability is embedded into selected civil engineering curricula. 

Through consultation with the HE built environment community, including industry and professional bodies, the research was evaluated and the results disseminated to those associated in built environment education.

Tailoring of acoustic materials from polymeric waste

The difficulty associated with recycling cross-linked polymers means that there are a limited number of technical solutions for the efficient large scale recycling of polymeric waste. However, the resistance of nylon fibres and rubber to biodegradation, both of which are disposed of via landfill in significant volumes, suggests that effective remedial measures need to be taken to convert this waste stream into a resource.  

Much of the research to date into polymeric waste recycling involves a wide range of chemical processes, in which the waste is converted by breaking the polymers into monomers. Dr Amir Khan and his colleagues have developed a novel cold extrusion method that deals with plastic and elastomeric residues, i.e. those that come in a range of particle shapes and sizes, and that are costly to separate into well-defined particulates. 

Also, and of relevance to the novel processing of rubber crumbs in their new approach, is the fact that the binder is not used merely to glue particulates together, but is designed to foam thereby producing a secondary porosity. This is the fundamental difference between their work and the work previously carried out with rubber crumb and other elastomeric wastes.

Effectively, the process organises a micro-porosity within the macro-porosity of the particulates-particulates voids. Consolidation then becomes a second order parameter in the control of porous structure. A feature of the process chemistry, carried out conveniently at ambient temperature, is the ability to tune the binding foam so that it can be made more or less porous, thus enabling granulated polymeric waste to be recycled into materials with acoustic properties equal or better than those commercially available.

Acoustic performance of reconstituted granulated waste is not an inherent property, but depends upon numerous factors, including porosity, particle size distribution, flow resistivity and elastic moduli. These factors are controlled by the ratio of grains to fibres, type of adhesive and by other chemical additives used in the consolidation process.

Tailoring porous materials from recycled polymeric waste raises the question of how porosity, pore size distribution and elastic moduli can be controlled. In general, the creation of porosity within the structure requires a study of the physical and chemical processes at a molecular level. In this way, the grains/fibres are allowed to be securely bonded together to achieve a porous product with good acoustical properties. Thus it is possible in this fashion to prepare tailored materials from waste that have a specific absorbance to serve a specific function.

Acoustic engineering and management team