index = g/2 + t · tan θ
Worked example 25 mm wall, 3 mm gap, 30° bevel, 60° root index 44.80 mm cap width 29.56 mm
NDT calculators · PAUT
Aperture, steering, focal laws, wedges and the acquisition arithmetic behind an encoded scan. Each of the 29 shows the governing formula, a worked example and the standard it comes from.
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index = g/2 + t · tan θ
Worked example 25 mm wall, 3 mm gap, 30° bevel, 60° root index 44.80 mm cap width 29.56 mm
Aperture, steering, focal laws, wedges and the acquisition arithmetic behind an encoded scan.
PAUT Sensitivity, scanning and data
Highest encoded scan speed that still records every acquisition point, from the frame rate and the scan axis resolution.
General engineering Free
PAUT Wedges and weld coverage
Natural refracted angle of a phased array wedge and the refracted angle range reachable with a given amount of electronic steering.
General engineering
PAUT Sensitivity, scanning and data
Gain needed at a TCG point relative to the reference point, from the far field reflector law and material attenuation, with a headroom check.
Engineering reference
PAUT Focal laws and focusing
Checks a requested focal depth against the near field length of the aperture and gives the element count needed to focus there.
Engineering reference
PAUT TFM and FMC
Maximum TFM pixel pitch from the wavelength, the resulting grid dimensions for a zone, and the delay-and-sum load per frame.
ASME V
PAUT Wedges and weld coverage
Bevel geometry, the angle that strikes the fusion face square, and the probe index positions needed to cover root and cap in leg 1 and leg 2.
ASME V · ISO 17640
PAUT Wedges and weld coverage
Half skip, full skip and the exit point stand-off needed to place a shear beam on a reflector at a given depth in leg 1 or leg 2.
General engineering
PAUT Focal laws and focusing
The −6 dB beam width at a focal depth, compared with the narrowest width the same aperture reaches unfocused.
Engineering reference
PAUT Focal laws and focusing
Per-element transmit delay for a direct contact or immersion linear array steering and focusing at a chosen angle and depth.
General engineering
PAUT Sensitivity, scanning and data
Gain that puts a reference reflector at the required screen height, plus transfer correction and the code scanning gain addition.
ASME V · ISO 17640
PAUT TFM and FMC
Worst case amplitude fidelity loss from TFM grid sampling, and the coarsest pixel pitch that still meets a 2 dB limit.
ASME V
PAUT Array and aperture
Checks inactive elements in an aperture against the usual 25 percent and no-two-adjacent limits, with the resulting sensitivity loss.
ISO 18563-3 · ASME V
PAUT Array and aperture
Active aperture size of a phased array group from element count and pitch, with the aperture expressed in wavelengths.
General engineering
PAUT Array and aperture
Near field length of a rectangular phased array aperture using the k factor for the active to passive aperture ratio.
Engineering reference
PAUT Array and aperture
Maximum useful steering angle set by the directivity of a single element, and the sensitivity lost at a chosen steering angle.
Engineering reference
PAUT Sensitivity, scanning and data
Frames per second from the pulse repetition frequency, law count and averaging, with the PRF ceiling set by the sound path.
General engineering
PAUT Array and aperture
Maximum element pitch that keeps grating lobes out of the propagating field over a required steering range.
General engineering
PAUT Array and aperture
Angle at which grating lobes appear for a given pitch and steering angle, so ghost indications can be recognised and plotted.
General engineering
PAUT Wedges and weld coverage
Gap between a flat wedge and a curved surface, whether contouring is required, and the pipe size band a contoured wedge covers.
ISO 17640
PAUT Sensitivity, scanning and data
Raw file size of an encoded phased array scan from samples per A-scan, law count, scan length and resolution.
General engineering
PAUT Sensitivity, scanning and data
Pulses per millimetre for a wheel encoder from wheel diameter, pulses per revolution and quadrature multiplier.
General engineering
PAUT Wedges and weld coverage
Wedge path, wedge delay and beam exit point for an active group on an angle wedge, from the first element height and the wedge angle.
General engineering
PAUT Array and aperture
Elevation beam spread and width of a linear array, set by the fixed passive aperture that cannot be steered or focused.
Engineering reference
PAUT Wedges and weld coverage
Number of focal laws, index resolution and coverage width for an electronic raster scan stepping a fixed aperture along the array.
General engineering
PAUT Focal laws and focusing
Axial extent of the −6 dB focal zone of a focused array beam, from the normalised focal depth.
Engineering reference
PAUT Wedges and weld coverage
Extra gain needed at a steered refracted angle relative to the wedge natural angle, from the longer wedge path and the element directivity.
General engineering
PAUT TFM and FMC
TFM frame rate from the delay-and-sum load and from the full matrix capture time, showing which of the two is the limit.
General engineering
PAUT Wedges and weld coverage
Number of parallel scan lines and the index offset between them to cover a required width with a specified overlap.
General engineering
PAUT Wedges and weld coverage
Number of focal laws in a sectorial sweep from the angular range and step, including multiple focal depths and groups.
General engineering
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