Abstract
Elastic wave velocities in metallic structures are affected by variations in environmental conditions
such as changing temperature. This paper extends the theory of acoustoelasticity by allowing
thermally induced strains in unconstrained isotropic media, and it experimentally examines the
velocity variation of Lamb waves in aluminum plates (AL-6061) due to isothermal temperature
deviations. This paper presents both thermally induced acoustoelastic constants and thermally
varying effective Young’s modulus and Poisson’s ratio which include the third order elastic
material constants. The experimental thermal sensitivity of the phase velocity (@vP=@h) for both the
symmetric and antisymmetric modes are bounded by two theories, the acoustoelastic Lamb wave
theory with thermo-acoustoelastic tensors and the thermoelastic Lamb wave theory using an
effective thermo-acoustoelastic moduli. This paper shows the theoretical thermally induced acoustoelastic
Lamb wave thermal sensitivity (@vP=@h) is an upper bound approximation of the experimental
thermal changes, but the acoustoelastic Lamb wave theory is not valid for predicting the
antisymmetric (A0) phase velocity at low frequency-thickness values, <1.55MHz mm for various
temperatures.
Original language | English |
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Pages (from-to) | 2532–2543 |
Number of pages | 11 |
Journal | Journal of the Acoustical Society of America |
Volume | 136 |
Issue number | 5 |
Publication status | Published - Nov 2014 |