Real-Life Communication
Sound waves are often used to test materials. You are a nondestructive
tester. You use ultrasonic testing to inspect equipment.
"When you
are testing, you have to write reports about what you find," says Blaine Whaley,
a nondestructive tester. "You have to be able to interpret codes. You also
have to be able to read and write well enough to get through the certification
process."
You are going out to a gas plant to inspect the welds in
their pipes. You take a student intern along with you. This is the first time
that Sarah has used ultrasonic testing. On the drive over, she wants to know
more about it. This is what you tell her:
Ultrasonic refers
to acoustic vibration frequencies greater than about 18,000 Hz. Ultrasonic
waves have a wide variety of applications. They can be used for such things
as physical acoustics and materials characterization. They can also be used
for surgery and therapy.
Nondestructive testers use ultrasonic test
equipment. The equipment includes the test instrument, probes, cables and
all other devices connected to the instrument. The test instrument, together
with the probe, transmits and receives ultrasonic waves.
The instrument
is often called an ultrasonic flaw detector because it is mainly used for
the detection of flaws. However, it is also used in a wide range of testing
for material imperfections and material characterizations. Examples are inspections
for stress, hardening, depth and thickness measurement.
(Summarized
description of ultrasonics from: Nodestructive Testing Encyclopedia,
by Rolf Diederichs. http://www.ndt.net/article/ut_az/ut_u/ut_u.htm)
Sarah has a few questions:
- What does ultrasonic mean?
- How does the ultrasonic test equipment work?
- What is the equipment used for?