Flat End Face Research Articles

On the state of stress and strain in a finite cylinder subjected to dynamic loads: PMM vol. 37, n≗4, 1973, pp. 724–730

A solution is presented of the dynamical axisymmetric problem of elasticity theory for a cylinder of arbitrary length with given displacements on its curved and planar surfaces. The initial non-self-adjoint equations are converted into equivalent first order equations for an extended eigenvector by introducing certain auxiliary functions. Arbitrary displacements given on the flat endface of the cylinder are expanded in series of eigensolutions of the problem by using these eigenvectors. Final formulas are obtained for the expansion coefficients. As a particular case, the solution of the statics problem of a cylinder [1] follows for ω → 0. An analogous problem has been examined in [2] where it was reduced to solving an infinite system of equations. The numerical method for solving problems of such a class has been elucidated in [3].

Magnetoelastic Waves in Yttrium Iron Garnet

Magnetoelastic rf pulses with magnetically controlled echo time have been observed in a rod of yttrium iron garnet. Data were taken at room temperature in the frequency interval 0.5 to 3.3 Gc/sec with power input in the milliwatt range. Excitation and detection was accomplished by placing a wire antenna near an optically flat end-face of the rod. A nonuniform internal magnetic field was obtained by applying a steady, uniform external field parallel to the rod axis. The frequency-time-magnetic field characteristics have been measured. The behavior of these pulses can be explained in terms of a magnetoelastic disturbance traveling along the rod axis. It originates at that position along the axis where ωc=γHi. From there the disturbance travels to the nearer polished surface where it is reflected. On arrival back at the launch site a fraction of the energy is detected and the remainder reflected for another round trip. The process is repeated several times to give rise to a pulse sequence.