The MATLAB®-based Dispersion Calculator is a free software for the computation of dispersion curves of guided waves in isotropic materials and anisotropic composites. The Dispersion Calculator was released under the GNU General Public License v3 in 2018 as version 1.0 for the first time and is available for download free of charge below.
What does the Dispersion Calculator do?
The Dispersion Calculator computes the frequency-dependent phase velocity, group velocity, excitation angle and internal stress- and displacement fields of Lamb- and shear horizontal waves in single layer isotropic- and multilayered, transversely isotropic materials such as composites. For composites you can also calculate polar dispersion diagrams at fixed frequencies to investigate the anisotropic behavior of the phase- and group velocity as well as excitation angle in any layup. The Dispersion Calculator features the capability of calculating laminates consisting of at least several hundreds of layers so that even the largest specimens, which we encounter at the DLR, for example in the rocket booster manufacturing, can be calculated. This is made possible by the implementation of the “Stiffness Matrix Method” invented by Rokhlin and Wang. The Dispersion Calculator is also able to distinguish the different mode families, like symmetric- and antisymmetric Lamb- and shear horizontal waves, depending on the symmetry and coupling properties of a given layup.
About the author
The Dispersion Calculator has been developed by Armin Huber since 2015. Armin Huber is researcher at the Center for Lightweight Production Technology (ZLP) of the German Aerospace Center (DLR), located in Augsburg, Germany. Here, production processes for large-scale air- and space craft vehicle components made of carbon composites are developed. Such components, like rocket booster pressure vessels for the future Ariane 6 launcher, can consist of up to 400 layers. Armin Huber works on the production process integrated quality assurance by using the method of air-coupled ultrasonic testing. The single-sided inspection mode is based on the excitation of Lamb waves in such composite laminates, which requires the adjustment of the correct excitation angle. Since commercial software failed to calculate Lamb wave dispersion curves for laminates consisting of several hundreds of layers, Armin Huber has written the Dispersion Calculator.