Ultrasonic-UR Flashcards
what are the two parts of a sound wave?
compression and rarefaction
what is the small group of ultrasonic waves called that occurs together and not immediately preceded or followed by other waves?
pulse
in ultrasonic testing, what does the wave type or mode refer to?
direction of particle motion
what is the number of sound waves that pass a given point in a given time called?
frequency
high-frequency sound waves do not permanently affect a test part because of their…
short wavelength and low energy level
what is the relationship between wavelength, velocity, and frequency?
the wavelength is equal to the velocity divided by the frequency
what characteristic of a crystal element determines ultrasonic transducer efficiency?
composition
what wave mode results in particle displacement at right angles to the direction of wave propagation?
shear
surface waves are introduced into the test part using an angle beam search unit which has a _______ ________ wedge?
steeply angled
what is the most probable cause for not receiving a return signal during pulse-echo testing?
geometry of the part
No ultrasonic reflection from a defect can be observed in the _____ ______.
dead zone
due to sound wave amplitude variations, ultrasonic inspection is not recommended in the ______ ______.
near field
Where does beam spread occur?
far field
what determines if the incident energy from a transducer is reflected at an interface?
differences in acoustic impedance at the interface
when a longitudinal sound beam is transmitted into a solid, what determines the mode of vibration?
incident angle of the sound beam
When using ultrasonic inspection, where does an undesirable mode conversion occur?
within the test specimen
which type of ultrasonic display has a baseline at 50 percent of full screen height and shows the full waveform with both positive and negative peaks?
radio frequency, non-rectified (RF)
what is the term for the horizontal line appearing on an ultrasonic display?
sweep
what fixed starting point on the ultrasonic display is usually used to start all time measurements?
initial pulse
what ultrasonic control determines the amount of time or the depth of the material displayed on the cathode ray tube (CRT)?
sweep length or range
on an ultrasonic flaw detector, which portion of a received signal does the gain control adjust?
amplitude
what ultrasonic instrument feature is used to detect discontinuity signals within a specified zone of the sweep?
flaw gate
what determines the frequency of preventive maintenance for an ultrasonic flaw detector unit?
severity of the environment
what reference governs the electrical safety requirements for using ultrasonic equipment around aircraft?
Air Force Occupational safety and health (AFOSH) standards
What method of ultrasonic testing uses a single transducer to transmit and receive the sound wave?
Pulse-echo
Which ultrasonic method relies only on a loss or reduction of received signal to indicate a flaw?
through-transmission
what type of transducer would you use to ultrasonically inspect welds?
an angle beam
when inspecting welds, what would you use an ultrasonic calculator card for?
the location of defects
What are some ways to confirm the presence of a suspected defect that is found ultrasonically?
1) with surface waves, clean the area in front of the transducer and re-inspect (2) inspect the suspected defect from another angle or with another transducer (3) re-inspect the part with another nondestructive inspection (NDI) method capable of detecting the defect
you would consider using an area-amplitude response when you are determining discontinuity ______.
size
the principle of ultrasonic thickness measurement is based on the _____ __ _____ __ ________ ___ ____.
speed of sound in material and time
which ultrasonic method is most commonly used for thickenss measurement?
pulse-echo
Accurate thickness measurements are possible only when the acoustic velocity in the reference standard is ___ ____ __ ___ ________ ________ __ ___ ____ ____.
the same as the acoustic velocity in the test part
In the American Society for testing Materials (ASTM) block, the flat bottom hole (FBH) diameters are measure in what increments?
sixty-fourths of an inch
To heck the baseline of horizontal linerarity of the cathode ray tube (CRT) sweep, you would normally use American Society for Testing Materials (ASTM) blocks with a _______ _____ ______ ________.
varying metal travel distance (MTD)
Area-amplitude blocks are used to check ________ _________.
vertical linearity
