Mechanical Performance of a Thermoelectric Composite in the Vicinity of an Elliptic Inhomogeneity

Abstract

Thermal stress induced by an uneven temperature field and mismatched thermal expansion is known to be a dominating factor in the debonding mechanism that threatens reliability and ultimately leads to failure in thermoelectric (TE) composites. Accordingly, we analyse the stress distributions in a TE composite induced by the presence of an elliptic inhomogeneity embedded in the surrounding matrix material. Using complex variable methods, we obtain closed-form representations of the thermal–electric and thermal–elastic fields and find that the temperature field around the inhomogeneity is reduced dramatically by the application of a remote electric current density without affecting the temperature difference across the inhomogeneity–matrix interface. This ensures the conversion efficiency of the TE composite while improving its reliability. Numerical results illustrate that a suitable choice of electric current density can prevent interfacial debonding via the suppression of the maximum positive normal stress on the interface.