ivan-pi / lamb-wave

Calculation of Lamb wave modes in a plate

wavemodes

Lamb mode eigenvalue computation following method of

Pagneux, V., & Maurel, A. (2001). Determination of Lamb mode eigenvalues. The Journal of the Acoustical Society of America, 110(3), 1307-1314. https://doi.org/10.1121/1.1391248

A PDF of the article can be downloaded freely on ResearchGate.

The script copper.m located in the current folder attempts to reproduce Fig. 4a of the original article.

Basis functions

The plot of the basis functions was produced using

n = 5
h = 0.01
a(n) = (n-1)*pi/h
b(n) = (n-0.5)*pi/h

set terminal pngcairo enhanced

set output "sym.png"
plot [-h:h] for [i=1:n] cos(a(i)*x) lw 3 t sprintf('n = %d',i)

set output "asym.png"
plot [-h:h] for [i=1:n] sin(b(i)*x) lw 3 t sprintf('n = %d',i)

Fortran code

A Fortran implementation of the wave mode calculator is in lamb.f90. To compile the code use:

gfortran -O3 lamb.f90 -o lamb -llapack -lblas

Running the code with the command $ lamb will produce a file eigvals.txt that can be plotted using gnuplot.