Plate Wave Modes Research Articles

Pulse-echo method of determining the elastic constants of rectangular strips and square plates

A sonar type pulse-echo system was used to excite in-plane vibration of rectangular and square plates. By examining the end resonance and plate wave mode on rectangular strip, the elastic constants could be calculated precisely. The authors studied the frequency spectrum on square plates and established that comparison of the breathing and two-diagonals mode frequecies (fb/fd) gives a very sensitive method of determining Poisson's Ratio (ν) and the linear relationship between fb/fd and ν should be useful in materials studies. Results on a number of materials including refractory materials have been obtained. Using this technique, the internal friction and elastic constants can be calculated over a wide temperature range.

Effect of Crystalline Anisotropy on the Magnetostatic Spin Wave Modes in Ferromagnetic Plates. I. Theoretical Discussion for Infinite Plates

AbstractThe dispersion equations of magnetostatic spin wave modes in thin ferromagnetic plates are derived within the linear phenomenological theory for a general anisotropic tensor of the dynamic susceptibility (Polder tensor). The equations are discussed for the two special cases of the effective magnetic field being parallel or perpendicular to the surface of the plate. In the Appendix the Polder tensor is derived for crystals with an anisotropic gyromagnetic ratio.

The coefficient of viscosity of water in absolute units

The properties of electromagnetic acoustic transducers (EMATs) for using the symmetrical vertical mode-(S0) Lamb wave and the shear horizontal fundamental mode-(SH0) plate wave were experimentally studied. The EMAT, consisting of a meandering coil and an electromagnet, can effectively transmit and receive the S0 mode Lamb wave and the SH0-mode plate wave in a thin metal plate. For ferromagnetic materials, such as steels, the magnetostriction is important for the transduction. The wave amplitude is not proportional to the static field strength, but is dependent on the magnetostrictive properties of the material. In this study, the amplitude and the phase of the S0 mode Lamb wave and SH0 mode plate wave generated by the EMATs are measured while changing the static field strength to the sheets. The amplitude of the S0-mode Lamb wave in a low carbon steel sheet initially decreases with a static field to the minimum value, then increases again accompanying the phase inversion by 180 ° and finally decreases without any phase inversion. The amplitude of the SH0 mode plate wave in a low carbon steel sheet initially increases to the maximum value with the static field, then decreases to the minumum value and increases again accompanied by a phase inversion of about 90 °. These data were discussed on the basis of the magnetostrictive curve to the magnetizing current of an electromagnet in low carbon steel sheets.