Forum Technical Discussions Re: creeping wave? Posted by: Andrew Cunningham (PID_3643), E-mail: Address, on July 09, 2008 at 02:27 : In Reply to: creeping wave? posted by : john howard , E-mail: Address, on July 08, 2008 at 01:11 : ----------- Start Original Message ----------- : Can anyone help? Is there or is there not a 'creeping wave'? Can it be proven either way? ------------ End Original Message ------------ John On this subject, I have to agree in part with Ed Ginzel. Not wanting to sound too controversial, I have to say there is no such thing as a ‘creeping wave’. When a shear wave hits the underside interface it will generate a small L wave, but this is not what generates a high amplitude signal (which is so commonly, but wrongly referred to as a ‘creep wave’ signal). This signal is just acoustics. Quite simply, it is the same phenomenon that occurs when you position stereo speakers at 45 degrees in the corner of a room to amplify the sound that is reflected from the 90 degree angle of the corner. The reflection will always return as a high amplitude reinforced signal at half the angle of the corner. For those of you interested, this topic and many others are explained in my book (see www.practical-ndt.com), a practical guide for manual ultrasonics written in a clear, concise way that will help you understand the propagation of sound. Andrew Cunningham Follow Ups: Re: creeping wave? Hermann Wüstenberg 17:33 Jul-09-2008 (0) Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : : Can anyone help? Is there or is there not a 'creeping wave'? Can it be proven either way? : John : : On this subject, I have to agree in part with Ed Ginzel. Not wanting to sound too controversial, I have to say there is no such thing as a ‘creeping wave’. When a shear wave hits the underside interface it will generate a small L wave, but this is not what generates a high amplitude signal (which is so commonly, but wrongly referred to as a ‘creep wave’ signal). : This signal is just acoustics. Quite simply, it is the same phenomenon that occurs when you position stereo speakers at 45 degrees in the corner of a room to amplify the sound that is reflected from the 90 degree angle of the corner. : The reflection will always return as a high amplitude reinforced signal at half the angle of the corner. : For those of you interested, this topic and many others are explained in my book (see www.practical-ndt.com), a practical guide for manual ultrasonics written in a clear, concise way that will help you understand the propagation of sound. : Andrew Cunningham ------------ End Original Message ------------ Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP Page Title: is important! Optional Image URL: http://www....gif Attention! Please click the button only once. This may take a moment to process Forum Technical Discussions Help