The viscoelastic properties of nine silicone-, polysulfide-, and polyether-based impression materials were determined using creep tests. During deformation the materials demonstrated linear viscoelastic behavior. The creep compliance curves, recovery, and percent set were calculated. Permanent deformation in these materials is a result of lack of recovery of elastic deformation as well as visco...

2. INTRODUCTION Piezoelectric effects are of increasing importance in the control and sensing of structural element deflections. Elastic piezoelectric theory has been extensively developed (Leibowitz & Vinson 1993). Hilton et al. (1997) have presented an extended bibliography and discussed past contributions as well as formulated an analytical nonlinear theory of anisotropic piezoelectric-therm...