Research Idea Details

Research Idea Scope

We propose a novel, flexible, cost-effective,
laptop-based, in-situ measurement system that will be capable of gathering all
necessary data in a practical way while also enabling the testing of a broader
range of variables, including the properties of various wall textures and
pavement surfaces. The proposed field-deployable system includes an integrated
sound-source and receiver apparatus, user-friendly software for controlling the
in-situ measurement, and advanced signal processing algorithms to evaluate the
acoustic absorption, surface reflection/impedance as function of frequency
between several hundred Hertz and 4-6 kilo Hertz, where the major frequency
ranges for noise propagation are needed for traffic noise prediction. The
proposed implementation/investigation will be fully practice-oriented and
suited for making measurements in the field. Surface reflection coefficients as
a function of frequency will provide needed information to allow for the
determination of the important acoustical parameters, such as noise-barrier
absorption and local ground impedance. With the proposed equipment setup, this
in-situ measurement system is easily deployable for practical use to provide
important field data on a wider range of variables for corroborating laboratory
test results thereby providing more exacting input to support new highway
noise-prediction models.

During this project, both practical implementation and
field tests will be conducted. The project includes:

• Implementation of a portable laptop-based in-situ
measurement system that allows the collection of field measurements of the
following properties: acoustic absorption; surface reflection/impedance of
typical highway noise barriers; ground properties; and roadway surfaces;

• The design of the system will fully consider ease of
practical deployment including: lightweight, battery-powered amplifiers for the
sound source and the microphone; a user-friendly graphical user-interface of
the controlling software; a tablet/laptop platform;

• Testing of multiple sites will be conducted to allow
comparison of the results of the implemented technique to information now being
used, and to allow various wall textures and pavement surfaces to be tested.
Specific instrumentation will meet requirements for practical field deployment and
will be documented during these field measurements.

Urgency and Payoff

In situ data on a number of key variables is needed to
accurately characterize the acoustic properties of highway infrastructure and
to enable accurate modeling and description of noise propagation.  Necessary data include: noise barrier
acoustic absorption and reflection/impedance, and properties of local ground
and road surfaces.  However, conventional
methodologies and techniques for doing practical, in-situ measurement have not
been developed thereby limiting the usefulness of studies. Instead, researchers
now rely on data measured in laboratory conditions. Unfortunately, laboratory
methods are time consuming, and usually destructive in nature.