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 -

408 views
Technical Discussions
Hermann Wuestenberg
R & D
BAM Berlin, Germany, Joined Nov 1998, 26

Hermann Wuestenberg

R & D
BAM Berlin,
Germany,
Joined Nov 1998
26
03:15 Mar-18-1998
Time reversed mirror technique

Responding to a remark of Prof. Fink

Dear Prof. Fink

The last hint in my short contribution about our experiences with the TMR approach ("the target is painted after the arrival of the arrow") is especially related to hopes and expectations in cases, which can not be solved by Autofocussing or TRM. The general value of this technique is not be called into question, but the example described below may clarify our reluctant position.
Strong focussing is regarded as an important tool especially for anisotropic and coarse grained materials like stainless steel castings or weldments. If for such materials the focussing is optimized for one position and one specific reflector (using suitable optimization strategies for the delay time repartition of the probe array), this is in those materials generally only valid for this specific position and could be totally wrong for a neighbouring area where with that focussing parameters a similar defect can be missed.
In order to avoid such an uncertainty for the detection probability, one should try to inspect the whole volume with sweeping focussing parameters. This is not only time consuming but also useless because the most essential contribution of an TMR approach at such materials is the possibility to define individually adaptable complicated delay time repartitions not simply being based on a curvature and a linear slope .
A sweeping focussing can only vary some parameters and not the whole multitude. That means that a TRM technique has severe limitations in case of dynamically changing propagation conditions like those encountered during the mechanical scanning of austenitic coarse grained material. This has nothing to do with the application in more static situations where the probe is not moved or where the propagation parameters (sound velocity etc.) of the material are constant.

With best regards

H. Wuestenberg


 
 Reply 
 

Product Spotlight

Ultrasonic Squirter/Gantry System

TecScan’s NDT Ultrasonic Gantry Systems are industrial Squirter scanners designed for non-destru
...
ctive quality testing and raster scanning of large structures and parts. The Gantry Systems are usually composed of an Industrial Mechanical Scanner and a Control Room with System Workstation.
>

NEW - TD Focus-ScanRX

The NEW Next Generation Advanced UT platform, TD Focus ScanRX - Also available as a card stack solut
...
ion. Key Improvements 1. Data acquisition is significantly faster than current design 2. Better aesthetic – closely aligns with HandyScan RX 3. Improved IP rating (Target IP66) 4. Ruggedized housing 5. Connectors are protected from impact and ingress 6. Integrated stand and separate retractable handle easy to keep clean) 7. Touchscreen with ruggedized display glass 8. 3-Axis encoder input
>

MANTIS

MANTIS is a compact, powerful and affordable flaw detector (16:64PR), dedicated to field operators
...
. This portable equipment offers standard (electronic-, sector-, compound scan, conventional UT for pulse-echo, dual array and TOFD inspections), and advanced phased-array (real-time TFM -Total Focusing Method). MANTIS benefits from the same intuitive and user-friendly interface (CAPTURE) than Gekko for easier inspections.
>

NOVO Armor 15 & NOVO Armor 22

The Armor Kit Contains the NOVO Armor, which provides additional mechanical protection to the NOVO 1
...
5WN & NOVO 22WN Detectors, the Armor Stand and a traveling soft cover. - Newest shock absorbent technology case - Water resistant design - Supports wired & wireless communication - Multiple positioning options - Tripod connection using the Built-in 1/4” threads - Simple Detector battery replacement
>

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