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 -

AT-Automation Technology GmbH
AT -Automation Technology is a systems house for industrial image processing. AT offers thermographic ndt systems as well as high-speed 3D sensors.

854 views
Technical Discussions
Protopappas Vasilis
Protopappas Vasilis
06:42 Dec-02-2003
Lamb wave dispersion equations

Hello,

Could anyone suggest a way to solve the Lamb wave dispersion equations? I want to plot the dispersion curves for a number of symmetric and antisymmetric modes, the equations, however, need a numerical evaluation.

Thank you in advance,

Vasilis Protopappas


    
 
 
Michael Conry
Student
University College Dublin, Ireland, Joined May 2002, 3

Michael Conry

Student
University College Dublin,
Ireland,
Joined May 2002
3
07:43 Dec-02-2003
Re: Lamb wave dispersion equations
----------- Start Original Message -----------
: Hello,
: Could anyone suggest a way to solve the Lamb wave dispersion equations? I
: want to plot the dispersion curves for a number of symmetric and
: antisymmetric modes, the equations, however, need a numerical evaluation.
: Thank you in advance,
: Vasilis Protopappas
------------ End Original Message ------------

Plotting the curves can be tricky. The easiest way is as follows:

Divide the frequency/phase-velocity (f/c) space up into small increments.

At each point within this space calculate the value of the
characteristic equation F(f,c)

Then do a contour plot of the resulting numbers, including just a
single contour (at F(f,c)=0)

This is easy to do with Matlab, and I have also done it with Gnuplot and
Python.

This is not an efficient way to plot the curves (it requires a lot of
calculations) but even for a multilayered plate I found it took a pretty
short length of time to prepare a nice dispersion plot.

Doing the job in a more rigorous way requires either that you use curve
following algorithms to plot the curves (e.g. find the solutions for a
particular value of phase velocity, then incrementally reduce the phase
velocity and find solutions at each subsequent point). A difficulty in
this case can be correct handling of the crossovers of the curves.

Best regards,
Michael



    
 
 
khash
khash
00:29 Nov-25-2006
Re: Lamb wave dispersion equations
Hello
I would really be appreciate if somebody ask me why in the lamb wave dispersion curves, just A0 mode close to zero as frequency be zero?
best regards
khash
khash1979@yahoo.com


    
 
 

Product Spotlight

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
>

Varex Imaging Large Field of View (FOV) Digital Detector Arrays (DDAs)

A larger FOV DDA can reduce the space and volume of the X-ray inspection system on the factory floor
...
, enable faster scanning times, better throughput and better resolution images at a lower dose. Customers can also save time and money. With these benefits in mind, Varex Imaging has designed a family of large FOV detectors (4343HE, XRD 1611, 4343DX-I, 4343CT) for our industrial imaging customers.
>

Ceram 35P (Panoramic)

The Ceram 35P is the panoramic brand new portable generators designed by Balteau NDT and is offeri
...
ng no less than 300kV, 5mA and 100% duty cycle for an incredible image contrast even at full power. It will will surely become a reference as it can be classified as a high power portable unit and can be operated with our CF2000 control unit but also with our well known Hand-X Wireless Remote Control.
>

AMIGO2

TSC Amigo2 - ACFM technology has developed a solid reputation for accurately detecting and sizing
...
surface-breaking cracks through paint and coatings. As the industry demands increased performance in speed, signal quality, and portability, it’s time for an evolution. It’s time for Amigo2.
>

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
s