Theoretical analysis of thermal performance on inhomogenous materials by piezoelectric photoacoustic technique

The theoretical and experimental research of detecting inhomogenous materials by piezoelectric photoacous-tic technique have been carried out. The expression of temperature fields in the inhomogenous materials and adjacent media are obtained by two mathematical transforms, the analytical solution of temperature field in inhomogenous materials is given when thermal diffusivity is assumed to be exponentially changed slowly. The piezoelectric signal expression is obtained by piezoelectric detection theory. The piezoelectric signal of inhomogenous materials can be detection at different frequency by piezoelectric photoacoustic detection system. The distribution of thermal diffusivity on inhomogenous materials can be determined by nonlinear fitting. The theoretical and experimental results are in good agreement.