Plane Harmonic Waves in a Microperiodic Layered Thermoelastic Solid Revisited.

In previous work a one-dimensional averaged theory of thermoelastic waves in a microperiodic layered infinite solid was proposed in which an eighth-order-in-time partial differential equation involving a high intrinsic mechanical frequency ΩM and a high intrinsic thermal frequency ΩT is a central equation. Also, the existence of two harmonic thermoelastic waves of a given frequency ω propagating in a positive direction normal to the layering was previously established when &OHgr;M&ThickSpace;→&ThickSpace;∞ and &OHgr;T&ThickSpace;<&ThickSpace;∞, or &OHgr;M&ThickSpace;<&ThickSpace;∞ and &OHgr;T&ThickSpace;→&ThickSpace;∞. The existence of two harmonic thermoelastic waves of a given frequency &ohgr; propagating in the positive direction normal to the layering is proved when &OHgr;M&ThickSpace;<&ThickSpace;∞ and &OHgr;T&ThickSpace;<&ThickSpace;∞. Also, a closed form of the associated velocities and attenuation coefficients is obtained. Numerical results illustrating propagation of the two waves in a particular microperiodic layered thermoelastic solid are included. [ABSTRACT FROM AUTHOR]