Abstract: Taking into consideration the torsional warping effect of thin-walled beams, this article derives the geometric equations, constitutive equations, and static controlling equations of active thin-walled beams with 1-3 piezoelectric fiber composites (PFC). Based on these, the active force and the deformation model are obtained for four typical types of active thin-walled beams with 1-3 PFC under the control of voltage. The analysis result shows that 1-3 PFC thin-walled beams possess active torsion ability, especially the pure active torsion ability with proper laminated modes. Rules are obtained and generalized for the variation of the active torsion ability with the volume ration of the piezoelectric fiber, its orientation, the applied electric field intensity, and the length of the thin-walled beam. The results of the example show that the theory proposed in this article has good precision and 1-3 PFC active thin-walled beams exhibit good active torsion characteristic suitable for the torsion degree of the controlled structure which will help extend the range of the controlled freedom of the structure and make it suitable for the torsion degree of controlled structures.

Key words: piezoelectric materials, thin-walled structures, warping, torsion characteristics