ANALYSIS OF FREE VIBRATIONS FOR RAYLEIGH - LAMB WAVES IN A MICROSTRETCH THERMOELASTIC PLATE WITH TWO RELAXATION TIMES

摘要

The propagation of free vibrations in a microstretch thermoelastic homogeneous isotropic plate subjected to stress-free thermally insulated and isothermal conditions is investigated in the context of conventional coupled thermo elasticity (CT) and Green and Lindsay (G-L) theories of thermo elasticity. The secular equations for the microstretch thermoelastic plate in closed form for symmetric and skew-symmetric wave mode propagation in completely separate terms are derived. At short wavelength limits, the secular equations for both modes in a stress-free thermally insulated and isothermal homogeneous isotropic microstretch thermoelastic plate reduce to the Rayleigh surface wave frequency equation. The results for symmetric and skew-symmetric wave modes are computed numerically and presented graphically. The theory and numerical computations are found to be in close agreement.