UT circuity vocab Flashcards
what characteristic will influenced the instrument and transducer?
it will influence the resolution, sensitivity and penetration
name the five circuit in an A-scan instrument for pulse echo.?
- clock timer
- transmitter
- sweep generator
- receiver
- CRT ( Cathode Ray Tube
provides the constant rate of pulses to be used as a time base for other circuits within the instrument.
clock timer
- Circuit of the flaw detector that sends the initial pulse voltage to both the transducer and receiver.
- input high voltage pulse (short duration) to the Piezoelectric element in the transducer. Tweep generator will input a voltage to the CRT, which causes an initial pulse and sweep display.
Transmitter
- That circuit of a flaw detector that receives both the initial pulse voltage from the transmitter and the returning echoes ( as voltage) from the transducer.
- sense the low voltage created when the piezoelectric element in the transducer and converts received mechanical energy to electrical energy. then the signal then the signal is amplified, filtered, and rectified and displayed onto the CRT.
Receiver
T.V monitor. two types of phosphorus being used are log and momentary persistence. long persistence creates a fading effect to indications displayed. momentary allows indications to appear as soon as electrons no longer bombarding it.
CRT. Cathode Ray Tube
changing the pulse repetition rate will affect the time between transmitted pulses. different forms include fixed, variable by switches , and variables by range control.
Pulse repetition rate
Changes the voltage applied to the Piezoelectric element. higher voltage excitation pulses result in deeper penetration.
Pulse energy
provide to match transmitter output to the resonant frequency of the transducer. provides maximum energy conversion between the transmitter and transducer.
pulse tuning
change the duration of the pulse applied to the Piezoelectric element. increasing it will decrease penetration and increase resolution.
pulse length (dampening)
provides calibrated adjustment for indication amplitude. used to make discontinuity size comparison.
Gain control
used to suppress low amplitude indications that appear on the CRT. any tuning or frequency control doesn’t change the frequency of the transducer
reject control
instrument capable of receiving and tuning to a specific frequency is considered a narrow band instrument. broad bandwidth- wide range of frequencies.
Band width
The measure of resistance sound encounters as it travels through a particular medium. it is equal in magnitude to the product of the sound velocity (c) multiplied by the medium’s density
Acoustic Impedance
The boundary between two media of differing acoustic of absorbing or dispersing the sound pulses reflected within the wedge.
Acoustic interface
A strong sound attenuating wedge on an angle beam transducer which has the function of absorbing or dispersing the sound pulses reflected within the wedge.
Acoustic Swamp
can be considered, for practical purposes, to be the point on the CRT display which represents the entry surface of the specimen
Acoustic Zero
As an indication on the CRT, the vertical height of an indication measured from the lowest to the highest point of the indication.
Amplitude
a testing technique in which the crystal is placed at an angle to the test surface so that ultrasonic waves enter the material in a direction angular to the test surface
Angle beam testing
A pulse-echo technique whereby the CRT display show the pulse travel time in the horizontal direction to which one can ascribe the corresponding sound paths. in the vertical direction the maximum value of the acoustic pressure echo amplitude received by the transducer is displayed.
A-SCAN
A reduction in strength of force. the gradual loss of energy as sound travels through a medium.
Attenuation
(back echo) the echo representing the side of the specimen opposite the side to which the transducer is coupled. this echo represents the thickness of the specimen at the point.
Back wall Echo
the point on the base of an angle beam transducer’s wedge from which the sound leaves the wedge and enters the specimen.
Beam Index Point
A diagram in which entire circuit stages or sections are shown by geometric figures.
block diagram
A sectional representation (cross section) of a test specimen, usually performed in an immersion system. this sectional representation can be in the form of a photograph or recorded display.
B-scan
The graduation of an instrument to enable measurements in definite units which will be used during scanning.
Calibration
A vacuum tube consisting essentially of an electron gun producing a beam of electrons which, after passing between horizontal and vertical deflection plates, falls upon a luminescent screen; the position of the beam can be observed by the luminescence produced upon the screen. Electric potentials applied to the deflection plates are used to control the position of the beam, and its movement across the screen, in any desired manner.
Cathode Ray Tube (CRT)
The period of the clock (time), ie., the amount of time elapsing between pulses of the lock
Clock Interval
A cable consisting of a central conducing wire together with a concentric cylindrical conductor, the space between the two being filled with a dielectric substance.
Coaxial cable
A material (usually a liquid) used between the transducer and the test specimen to eliminate air from this space, and thus insuring the passage of sound waves into and out of the specimen
Couplant
Either the largest tolerable defect or the smallest intolerable defect. the critical defect size is usually given by the specification
Critical Defect
A plan view of a test specimen usually performed in an immersion system. this plan view is displayed by a recorder presentation
C-scan
Effectively reduces the ringing or oscillating of the Piezoelectric crystal by allowing a variably decrease in the initial pulse voltage sent from transmitter to the crystal.
Damping (control)
A unit of sound measurement, a unit which compares levels of power.
Decibel
A general term applied to all cracks, inclusions, blow holes, slags, etc… not normally found in the material. each of which will reflect sonic energy
Discontinuity
The scattering of the sound waves of an Ultrasonic beam because of reflection from a highly irregular surface, composed of many reflecting surfaces of different orientation in respect to the test surface.
Dispersa
A method of flaw evaluation that uses a test block with a known size reflector, at varying distances from the search unit. this allows plotting of a curve on the CRT that represents the amplitude of that reflector throughout time. this curve shows loss of energy due to beam spread and attenuation ( ASME)
Distance Amplitude Correction ( DAC)
A transducer containing two Piezoelectric crystals, one of which only transmits sound, the other only receives sound.
Dual Element Transducer
Signifies the peak height of the echo as displayed in a linear form on the CRT (usually above the baseline)
Echo Amplitude
The point in time when the transmitter fires the initial pulse ( Voltage) to the transducer and receiver, and the point on the CRT where the electron bam leaves the baseline due to the initial pulse signal coming from the transmitter.
Electrical Zero
That portion of the sound beam where interference effects cease to exist.
Far Field
The minimum incident angle in the wedge at which the refracted longitudinal wave is eliminated from the test specimen
First Critical Angle
The number of complete cycles undergone or produced by an oscillating body in one second
Frequency
A term used in electronics with reference to an increase in signal power.
Gain
Amount of calibrated gain available within the instrument
Gain Control
Plates, place one on each side within a CRT that can be variably adjusted with respect to the speed in which they change polarity, thus causing the electron beam to sweep left and right across the horizontal trace.
Horizontal Deflection Plates
A test method, useful for testing irregularly shaped parts, in which the part to be tested is immersed in water ( or other liquid) so that the liquid acts as a couplant. the search unit is also immersed in the liquid, but not in contact with the part being tested.
Immersion testing
The angle between a sound beam striking an interface and the normal angle to the surface at that point
Incidence, angle of
A signal or response vertically appearing from the baseline of the CRT caused by, and indicative of, an echo from the material under test.
Indication
The number of decibels of calibrated gain which must be set on the instrument to bring the indication echo (signal) to peak at the reference amplitude.
Indication level (defect)
The pulse of electricity sent by the transmitter to the receiver and transducer
Initial pulse
The metric prefix signifying one thousand (1000)abbreviated ‘k’
Kilo
Mode of wave propagation characterized by article movement parallel to the direction of wave travel.
Longitudinal wave
The loss of sound pressure in a traveling wave-front caused by the reflection or the absorption of some of the wave’s sound energy due to the grain structure and/ or porosity within the medium being tested.
Material Loss Attenuation (MLA)
A substance through which a force acts or an effect is transmitted; surrounding or enveloping substance, environment.
Medium
The metric prefix signifying one million (1,000,000) abbreviated M’’
Mega
The metric prefix signifying one millionth (1/1,00,000) ‘u’
Micro
The changing of a portion of a sound beam’s energy into a wave of the opposite mode due to reflection and / or refraction at incident angles other than normal(zero degrees)
Mode Conversion
That portion of the sound beam directly in front of the Chrystal where interference (constructive and destructive) can occur.
Near Field
A device that can produce vibrational waves in a medium
Oscillator
Maximizing the height of any indication displayed by positioning the main axis of the sound beam directly over the reflector
Peaking up
The ability of the test system to overcome material loss, attenuation; ie the ability of the sound beam to by-pass small reflector such as grain boundaries and porosity in the specimen
Penetration
A family of crystals which posses the characteristic ability to produce 1) a voltage differential across their faces when deformed by an externally applied mechanical force, and 2) a change in their own physical configuration when an External voltage is applied
Piezoelectric crystal
Slang term for transducer or search unit
Probe
A wave disturbance of short duration
Pulse
Increase or decreases the amount of voltage applied to the transducer and receiver, thus effecting the ringing time of the piezoelectric Chrystal.
Pulse energy (control)
The frequency with which the clock circuit sends out its trigger pulses to the sweep generator and the transmitter, usually quoted in terms of pulses per second
Pulse Repetition Rate
The distance represented by the entire sweep (horizontal) display
Range
The circuit of a flaw detector that receives both the initial pulse voltage from the transmitter and the returning echoes (as- voltages) from the transducer.
Receiver
The echo from a reference reflector. may be adjusted to specific amplitudes.
Reference echo
The number of decibels of calibrated gain which must be set on the instrument to bring the reference reflector to a peak at the reference line on the display
Reference level
A REFELCTOR OF KNOWN SIZE AT A KNOWN DISTANCE, SUCH AS SIDE DRILLED HOLE, OR FLAT BOTTOM HOLES
RECLECTANCE, ANGLE OF
The bending of sound beam when it passes through an acoustic interface at an incident angle other than normal. The bending is caused by the difference in wave speed on either side of the interface, thus the refraction is accompanied by a change in wavelength
Refraction
The angle between a refracted sound beam and the perpendicular.
refracted, angle of
Also known as suppression, affect the input sensitivity of the amplifier in the receiver. ‘Grass” or metal noise can be reduced or eliminated from the display by its use. on most instrument I destroys the vertical linearity relationship between echo height.
Reject (control)
The ability of the test system ( instrument and transducer) to distinguish reflectors at slightly different depths, those that lie close together
Resolution
If, to a system capable of oscillation, a small periodic force is applied, the system is in general set into forced oscillations of small amplitude. as the frequency, “ f” of the exciting force approaches the natural frequency of the system, “fo” the amplitude of the oscillations builds up, becoming a maximum when f=fo. the system is then said to be in resonance with exciting force, or simply in resonance
Resonance
A wire coil in the body of the transducer which forms a tuned circuit, assuring maximum efficiency at the stated frequency
Resonance Coil
The minimum incident angle in the wedge at which the refracted shear waves leave the body of the test specimen
Second critical angle
The ability of the test system ( instrument and transducer) to detect a given size reflector at a given distances.
Sensitivity
Mode of wave propagation characterized by particle movement perpendicular to the direction of wave travel
Shear wave (transverse Wave)
The surface distance which represents one V-path of sound in the material (angle beam testing)
Skip Distance
Of or relating to frequencies within the audible range (the range of human hearing) ie., between 20 and 20,000 cycles/ sec. (hertz)
Sonic
The characteristic shape of the ultrasonic wave sent into the material
Sound Beam
The distance from the transducer beam index to the reflector located in the specimen, measured along the actual path the sound travels. sometimes referred to as angular distance in angle beam inspection
Sound Path Distance
The document which prescribes approves to be followed in a test
Specification
(Normal Incidence) A transducer which transmits the sound into the material perpendicular to the entry surface
Straight beam transducer
OF or relating to frequencies below the audible range,. below 20 cycles/ sec (Hertz)
SUB-sonic
Of or relating to movement through some medium at speed at speeds greater than the speed of sound in that medium.
SUPER-sonic
The uniform and repeated movement of an electron beam across the CRT
Sweep
Mode of wave propagation characterized by an elliptical movement of particle (molecule) on the surface of the specimen, this movement penetrates the specimen to a depth of proximately one wavelength
Surface Wave (Rayleigh)
Circuit of the flaw detector that reverses the polarity of the horizontal deflection plates, thus enabling the electron beam to sweep left and right across the CRT
Sweep Generator
Special blocks, used as standards, prepared to facilitate the setting of the instrument for test calibration.
Test Block
A test method in which the vibrations emitted by one search unit are received by another separate unit. The ratio between quantity of vibration sent and received is a measure of soundness, or quality of the material being tested.
Through Transmission
Circuit that automatically adjusts the gain so that echo amplitudes of a given size reflector is displayed at a constant screen height regardless of the distance to that reflector
Time Corrected Gain (TCG)
The illuminate line of the screen of the screen of a Cathode Ray Tube caused by the luminescence of the phosphor layer by the electron beam
Trace
any device that transforms one form of energy into another
Transducer
Circuit of the flaw detector that sends the initial pulse voltage to both the transducer and receiver.
Transmitter
Of or relating to frequencies above the audible range, ie greater than 20,000 cycle/sec (Hertz)
Ultrasonic
The study of pressure waves which are the same nature as sound waves, but which have frequencies above the audible limit.
Ultrasonics.
The top and bottom plates of the CRT THAT ARE CONTROLLED BY THE RECEIVER SUB-CIRCUIT. THEY VARY THE ECHO AMPLITUDE AS DISPLAYED ON THE CRT AS A FUNCTION.
- amount of gain set into the instrument.
- size of the reflector
- distance to the reflector
vertical deflection plates
THE ANGULAR DISTANCE SOUND TRAVELS, MEASURED FROM THE TOP SURFACE OF THE MATERIAL TO THE BOTTOM, REFLECTING BACK UP TO THE TOP SURFACE.
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