Remote Health Monitoring for Asset Management

are potted in the epoxy, the sensors are fixed and will not move. The sensors were placed such
that they are close to the armor channel in which the array is mounted. Figure 5.2 shows the
armored sensor housing during the construction of the sensor array. The Figure shows the
threaded studs that are welded to the steel channel, plastic stand-offs used to set the sensor array
at a constant elevation in the cross-section, and the rigid circuit board with the sensors attached.
As noted earlier, the sensors are mounted in a through-hole fashion such that the sensor leads
project through the circuit board and are actually soldered to the board on the opposite side of the
circuit board.
Conductive trunk lines
Plastic stand-off
Welded stud
Sensor
Figure 5.2. Photograph of the assembled sensor array showing plastic stand-offs, welded studs, sensors and
conductive trunk lines.
The channel armor was assembled in the laboratory with studs welded along the armor channel
to secure the circuit board materials in the channel. The 24 in. sensor assemblies were fabricated
in the electronics shop to ensure secure solder connections for each of the sensors in order to
provide long-term durability of the connection. Following the assembly and initial testing to
ensure that all of the sensors were functional and operating as anticipated, the entire array of 64
sensors was potted in epoxy to secure the sensors. The two part epoxy was mixed in the lab and
poured into the channel to submerge the sensor array and the circuit board entirely in epoxy.
Figure 5.3 shows the process of placing the epoxy in the channel sections to pot the sensor array.
Figure 5.3 A shows the soldering of the connections between the 24 in. circuit board units,
Figure 5.3B shows mixing the epoxy in the laboratory in preparation of placing the epoxy in the
armored channel. Figure 5.3C shows a photograph of the epoxy placement in the armored
channel with part of the board already submerged in epoxy. Figure 5.3D show a photograph of
28