On the theory of generalized thermoelasticity for piezoelectric materials Baljeet Singh Department of Mathematics, Government College, Sector-11, Chandigarh 160 011, India Abstract The governing equations for generalized thermo-piezoelectric solid are formulated by using Green–Lindsay and Lord–Shulman theories. These equations are solved for two- dimensional model. It is found that there exists three plane waves in a two-dimensional model of thermo-piezoelectric solid. The velocities of these plane waves are found to depend upon properties of material and the angle of propagation. Ó 2005 Elsevier Inc. All rights reserved. 1. Introduction The heat conduction equations for classical uncoupled and coupled theories of thermoelasticity are of the diffusion type predicting infinite speed of propa- gation of heat wave, which is not physically admissible. To eliminate this par- adox of the classical theories, the theories of generalized thermoelasticity were developed. These theories of generalized thermoelasticity admit so-called sec- ond-sound effects, that is, which predict only finite speed of propagation of heat wave. At present, there are various theories of generalized thermoelastic- ity, but the theories developed by Lord and Shulman [1] and Green and Lind- 0096-3003/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.amc.2005.01.046 E-mail address: baljeet_gill@hotmail.com Applied Mathematics and Computation 171 (2005) 398–405 www.elsevier.com/locate/amc