Ultrasonic
Angle-beam skip distance and sound path
Skip and sound-path distances for a plate and a refracted angle, and where a reflector sits from its sound path.
For reference only — verify against your procedure and the governing code.
Result
- Half skip (surface)
- 25mm
- Full skip (surface)
- 50mm
- Sound path, one leg
- 35.36mm
- Sound path, full vee
- 70.71mm
Locates a reflector from the screen reading.
Formula
- Half skip = T · tan θ; Skip = 2T · tan θ
- Leg sound path = T / cos θ; V path = 2T / cos θ
- Surface distance = SP · sin θ; depth from SP · cos θ folded at each leg
Units. Thickness and sound path in mm or in.; the distances come out in the same unit. Angles are in degrees in both systems.
Assumptions and limits
- A flat plate with parallel surfaces. Curved parts and weld crowns change the geometry.
- Surface distance is from the beam exit point, not the front of the wedge.
Sources
- ASTM E1316-09a, Standard Terminology for Nondestructive Examinations — Section I: decibel, near field, skip distance.
More ultrasonic calculators
For reference only — verify against your procedure and the governing code.
Standards and documents are cited by their publishers' names to identify them. TRACE is not affiliated with, endorsed by or sponsored by ASTM International, ASME, the U.S. Nuclear Regulatory Commission, NIST or the Laboratoire National Henri Becquerel. Formulas are paraphrased and cited by clause; get the documents themselves from their publishers.