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WISAN-based Load Testing System allows establishing loading
profiles for various structures.
The Load Testing System employs high-precision wireless strains sensors in
conjunction with user-friendly software for network configuration, and collection and
processing of strain data.
Upon startup the user is presented with
a choice to load data from a hard drive
for review and analysis or to start a new
experiment (Figure 1).

The network setup tab contains an
indicator that displays the status of the
network.
The
only
user-selectable
option is whether the strain sensor on
the sensor nodes needs to be powered
up.

The experimental setup screen contains
parameters set for a given experiment
(Figure 2):
Title and Description
Structural geometry and location
of each sensor on the structure
Calibration coefficients for each
sensor
Sampling frequency and duration
of each data recording
Selection of excitation voltage
applied to strain sensors
Experimental setup screen also allows
users to save and load experiments
setting, so for given sensor hardware
the calibration coefficients will need to
entered only once and loaded from disk
on subsequent uses.

Figure 1. Startup screen of the Load Testing System
Figure 2. Experimental Setup screen.
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Data
collection
screen
controls
the
wireless
sensors and presents users
with a plethora of options
for establishing correctness
of acquired data:

Each
data
point
is
associated with a certain
load
value
and
load
position on the structure
Data
is
collected
simultaneously
and
synchronously from all
wireless sensors allowing
utilization of strain data
in modal analysis
The time series data display and a
histogram allow for visual control
over the data quality for each
sensor. Data statistics computes
mean,
standard
deviation,
variance, min and max values.
Collected data can be either
accepted and saved on hard drive
as a data point for current
experiment, rejected or used to
adjust offset of the zero level
(offset drift is common in strain
sensors due to changes in ambient
temperature,
light
and
other
conditions)

Data processing screen
allows visualization of
collected data points and
generation
of
reports
(Figure
4).
Data
visualization is possible
for a set of certain
sensors, load values, etc.

Report generation option
saves the data in HTML
format
that
can
be
imported
into
text
editors such as Microsoft
Word or viewed in any
Internet browser (Figure
5).
08/08/2006
Figure 3. Data collection screen.
Figure 4. Data processing screen.
Figure 5. Beam setup and HTML report for load profile of an 8' aluminum
beam (no data point was taken in the middle location of the beam)