where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

342 views
Technical Discussions
Daron Branson
Daron Branson
02:19 Jan-21-2003
Ultrasonic Testing

Could someone please explain in detail the 6 dB drop method?


 
 Reply 
 
Ed Trotter
Ed Trotter
02:36 Jan-22-2003
Re: Ultrasonic Testing
: Could someone please explain in detail the 6 dB drop method?
.
The 6dB drop method has been used for flaw sizing for many years. However it has been proven that it is not very accurate for the sizing of reflectors, which are smaller than the width of the beam at the sound path where the reflector is located, unless beam spread measurements are taken and compensated for.

For example, if you have a reflector response at 80% full screen height (FSH) and you move the search unit until the reflector drops to 40% FSH, you have reduced the signal by 50% or 6dB. There is a formula to calculate this. ((A1/A2 Log) x 20).

Theoretically, if a reflector is larger than the beam width and you move the probe until the signal is reduced by half (-6dB), that will give you the end points of the reflector.






 
 Reply 
 

Product Spotlight

FD800 Bench Top Flaw Detectors

The bench-top FD800 flaw detector range combines state-of-the-art flaw detection with advanced mater
...
ial thickness capabilities. Designed for use in the laboratory these gauges are the tool you need for all your flaw detecting needs.
>

VeeScan AirCraft Wheel Inspection

The VEESCAN offers maximum flexibility, has a proven mechanical design and records of breakdown-fr
...
ee operation of over 365 days. Appealing to companies in the Aerospace industry, the VEESCAN is ideal for all wheel-testing environments. With a wide selection of probes, the VeeScan allows your wheel testing facility the flexibility to select the most compatible configurations with their workload.
>

Ultrasonic Probe Recharacterization Service

NDT Systems offers a comprehensive Aftercare and Recharacterization Service for all our ultrasonic
...
probes. The Recharacterization Service is fully compliant with International ASTM E1065 Standard Guide (and other applicable standards) and offers complete documentation, traceable to the ASTM E1065 Standard. For more details or to schedule Recharacterization Services contact ndtsales@ndtsystems.com
>

IntraPhase Athena Phased Array System

The Athena Phased Array system, manufactured by WesDyne NDE Products & Technology, consists of a pha
...
sed array acquisition system and PC running IntraSpect software. A PC is used to perform acquisition, analysis and storage of the data. System hardware is capable of operating up to four data sets with any combination of phased array or conventional UT probes. NOW AVAILABLE IN 64-64 CONFIGURATION.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window