Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
50 Cards in this Set
- Front
- Back
Acoustic impedance is identified by the letter:
|
Z
|
|
What could influence the behavior of a transducer? |
Electrical construction
Material construction Mechanical construction |
|
Which type of transducer can be used to scan wide areas when high sensitivity is not required?
|
Paint brush transducer
|
|
What type of set-up can provide information about both the size of the flaw and distance between the flaw and the transducer?
|
Pulse echo
|
|
The sound that emanates from a piezoelectric transducer originates:
|
From most of the active surface
|
|
The frequency marked on a transducer indicates:
|
The center frequency at which the transducer operates
|
|
Which type of calibration block is used to determine the resolution of angle beam transducers per requirements of AWS and AASHTO?
|
An RC block
|
|
Which of the following waves is able to follow a surface around a curve?
|
A surface wave
|
|
DAC stands for:
|
Distance Amplitude Correction
|
|
A decibel is:
|
A logarithmic unit that describes a ratio of two measurements
|
|
In order to have a reasonable chance at detecting a discontinuity, the reflective surface of the discontinuity must have a dimension that is at least as long as ________ wavelength.
|
One-half
|
|
Artificial flaws can be produced by using:
|
Side drilled holes
Flat bottom holes EDM notches |
|
A 6dB change in the measured ultrasonic signal strength indicates that the sound intensity changed by a factor of :
|
Two
|
|
Some transducers are specifically fabricated to be:
|
Better transmitters
Better receivers Used in high temperature applications |
|
Longitudinal waves are also called:
|
Pressure waves
Compressional waves |
|
What is the material called that is used to improve the transmission of ultrasonic sound energy from the transducer into the part?
|
Couplant
|
|
What part of the ultrasonic machine generates short, large-amplitude pulses of controlled energy?
|
Pulser
|
|
Which type of calibration block closely resembles the miniature angle-beam block and is used in a similar way?
|
A DSC block
|
|
Within a given material, the speed of sound:
|
Is constant
|
|
The total resistance that the cable presents to the electrical current passing through it is called:
|
Impedance
|
|
In angle-beam testing, when the geometry of the part is relatively uncomplicated and the orientation of a flaw is well known, the length of a crack can be determined by a technique known as:
|
Tip diffraction
|
|
Which of the following ultrasonic techniques require the probe to be held firmly against component?
|
Contact inspection
|
|
Mode conversion, occurs when a sound wave encounters an interface between materials of different acoustic impedance and:
|
The incident angle is not normal to the interface
|
|
What Greek letter is used to represent wavelength?
|
lambda (λ)
|
|
The terms used to describe a technique�s ability to locate flaws are:
|
Sensitivity and resolution
|
|
Ultrasound is generally defined as sound at frequency above the threshold of human hearing, which is?
|
20,000 Hz
|
|
Less damped transducers will exhibit:
|
A narrow frequency range
|
|
The ability to locate a small discontinuity is called:
|
Sensitivity
|
|
When a longitudinal wave encounters an interface between two material with different accoustic impedances, what occurs when the angle of incidence is 90 degrees?
|
Reflection
|
|
The sound energy or ultrasonic beam is more uniform in the:
|
Far field zone
|
|
Snell's Law describes the relationship between the sound velocity and:
|
The refracted angle of the wave
The reflected angle of the wave |
|
Contact transducers are used for direct contact inspections, and are generally:
|
Hand manipulated
|
|
Resolution generally increases:
|
With an increase in transducer frequency
|
|
As frequency increases, sound tends to:
|
Scatter more from large or course grain structure
|
|
Which type of test block is used to check horizontal linearity and the dB accuracy per requirements of AWS and AASHTO?
|
Distance/Sensitivity block
|
|
When sound travels through a medium:
|
Its intensity diminishes with distance
It spreads perpendicular to the primary direction of wave travel Its speed remains constant |
|
The combined effect of scattering and absorption is called:
|
Attenuation
|
|
Shear waves do not propagate in:
|
Gases
Liquids |
|
When an ultrasound wave passes through an interface between two materials at an oblique angle, and the materials have different indices of refraction, it produces:
|
Reflected waves
Refracted waves |
|
Couplant displaces the__________ and makes it possible to get more sound energy into the test specimen.
|
Air
|
|
Which of the following would make a good couplant?
|
Water
Oil Glycerin |
|
The a large acoustic impedance mismatch at an interface will result in:
|
A high amount of reflected sound energy
|
|
The first critical angle describes the condition where the:
|
The angle of the refracted longitudinal wave is exactly 90o
|
|
Which type of screen presentation displays the amount of received ultrasonic energy as a function of time?
|
A-scan
|
|
Which type of screen presentation displays a profile or cross-sectional view of the test specimen?
|
B-scan
|
|
Which type of screen presentation displays a plan-type view of the location and size of the test specimen features?
|
C-scan
|
|
Sound can propagate as:
|
Longitudinal waves
Shear waves Surface waves |
|
Why aren't real defects commonly used in calibration and reference standards?
|
It is cost prohibitive to produce them
|
|
What is used to establish a general level of consistency in measurements, and to help interpret and quantify the information contained in the received signal?
|
Reference standards
|
|
Which of the following waves is only able to travel through a thin section of material?
|
A lamb wave
|