Thermoelastic Stress Production in Solids

Theoretical calculations of the consequences of the thermoelastic mechanism for production of stress in solids by pulsed energy input have been performed, and the effect of variations in the acoustic impedance of a transparent backup material and variations in the pulse duration as compared to the acoustic transit time across the penetration depth of the incident energy have been investigated. Experimental verification of the theoretical calculations has been done using a Q-switched ruby laser as an energy source with samples of absorbing glass as targets. It is found that the experimental results give good agreement in the shapes of the stress pulses produced, and fair agreement in the absolute amplitude of the stress, with no adjustable parameters being required. The calculations and experiments demonstrate the validity of the thermoelastic stress-production mechanism in solids when no phase transformation occurs.