Could anyone help me with mathematical formulae to calculate resonant frequency of a material. For eg. calculating resonant modes of a cylindrical steel block.

00:27 Jan-24-2004 N.Kuppusamy Consultant, NDT Level-III Engineer Advanced Inspection & Testing (S) Pte Ltd, Singapore, Joined Dec 2003 ^{34}

Re: Calculating resonant frequency Dear Lakshmi Srinivasan, I presume that you are asking for Resonance frequency for UT. The resonance condition for UT is established when, Wavelength = Thickness/2 and its multiples.

For resonance frequency of Eddy current you have to give more details such as Thickness, Capacitance and Inductance of the coil.

N.Kuppusamy

----------- Start Original Message ----------- : Hi all, : Could anyone help me with mathematical formulae to calculate resonant frequency of a material. For eg. calculating resonant modes of a cylindrical steel block. : cheers, : Lakshmi ------------ End Original Message ------------

If you are after modal resonant frequencies for cylindrical samples that have aspect ratios (length to diameter) very large (e.g., greater than 30 to 1), you may calculate the longitudinal and transverse mode frequencies quite easily. However, when the aspect ratio decreases, the solution is not nearly as straight forward. There are computer programs out there that will provide solutions for simple shapes (cylinders, parallelepipeds, and spheres) because they are relaticvely straight forward. One reason that textbooks really do not cover solutions to the small aspect ratio problem is that they are very complex (Bessel type solutions in closed forms), but are much easier to solve with modern computer programs. Additionally, the harmonics for most modes, if not all, depending on shape, are no longer even multiples of the funbdamental frequencies. Please contact me and I can give you more information. We have been dealing with this type problem for a some time, now.

M. Kim Johnson.

----------- Start Original Message ----------- : Dear Lakshmi Srinivasan, : I presume that you are asking for Resonance frequency for UT. The resonance condition for UT is established when, : Wavelength = Thickness/2 and its multiples. : For resonance frequency of Eddy current you have to give more details such as Thickness, Capacitance and

Inductance of the coil. : N.Kuppusamy : : Hi all, : : Could anyone help me with mathematical formulae to calculate resonant frequency of a material. For eg. calculating resonant modes of a cylindrical steel block. : : cheers, : : Lakshmi ------------ End Original Message ------------

04:06 Jan-27-2004 N. Kuppusamy Consultant, NDT Level-III Engineer Advanced Inspection & Testing (S) Pte Ltd, Singapore, Joined Dec 2003 ^{34}

Re: Calculating resonant frequency Sorry, I made a mistake. The resonance frequency is not Wavelength = T/2

The resonance condition is established when: Thickness of material = Wavelength/2 and its multiples

In other words, Resonance Frequency = Sound Velocity in the Material/2T

Where T = Material thickness.

This equation can be used to calculate the Piezoelectric crystal thickness also.

N.Kuppusamy ----------- Start Original Message ----------- : Dear Lakshmi Srinivasan, : I presume that you are asking for Resonance frequency for UT. The resonance condition for UT is established when, : Wavelength = Thickness/2 and its multiples. : For resonance frequency of Eddy current you have to give more details such as Thickness, Capacitance and Inductance of the coil. : N.Kuppusamy : : Hi all, : : Could anyone help me with mathematical formulae to calculate resonant frequency of a material. For eg. calculating resonant modes of a cylindrical steel block. : : cheers, : : Lakshmi ------------ End Original Message ------------