README_90-conclusion Synchronization of all six animations (a_90 thru f_90) in this directory reveals the fastest wave speed in the 24 elements per wavelength animation. It was necessary to create a large (1264x1369) frame size to observe the necessary L, T, QT, and QL grid deformations in each animation syncronized into the comparative collage. Together these animations demonstrate dispersion. The comparative collage of six animations for 4-8-12-16-20-24 elements per wavelength is shown in the previous directory. In this directory smaller (1264x984) frame size animations compare 4-8-12-16 and 12-16-20-24 elements per wavelength. The dispersive FEM wave speed is compared with the exact wave speed for a continuum. exact wave speed = sqrt ( shear stiffness / density ) The trend observed here is the FEM wave speed approaches the exact wave speed when larger number of elements are used to simulate one wavelength over the width of the simulated transducer. It appears the difference in wave speed for 20 and 24 elements is less than the difference in wave speed for 16 and 20 elements. This suggests the FEM wave speed is converging to the nondispersive (continuum) state with increasing number of elements. There is no wave speed for 4 elements per wave length, because in this case there exists only two elements per wave length for the QT wave at the 0 degree orientation. This result is similar to the exact solution of the one-dimensional spring-mass model where it is shown that group velocity (energy flux) is zero when the propagating wave length is equal to the twice the distance between masses. ?remember the ESM5344 class notes? When compared with the 0-degree fiber orientation case, there are major differences. Although the wave wave velocity is the same as predicted the wave shape is very different. The wave for the 90-degree case is more spread out in the horizontal direction. This spread is caused by the Poisson's contraction in the vertical direction. -- R.D. Kriz