A novel method for characterizing a high actuating capability light-weight actuator is described and analyzed. The actuator comprises a truss core and smart face-sheets which result in bending. The deformation of this beam actuator is obtained by changing voltage inside face-sheets made from smart material. Materials selections are discussed for practice, and then optimization is designed to ascertain minimum weight or maximum achievable displacement subject to two types of constrains. Results show the composite trusses have higher stiffness and strength than metal trusses. Comparisons with two corrugated core actuators, the truss-core design has better actuating capability at specified weight.