Stress analysis of sandwich composite beam induced by piezoelectric layer.

Introduction: Smart structures equipped with piezoelectric devices to sense and actuate the structure could be used in many engineering applications. To explore the smart structure further and apply it to more complex structures, some problems are critical to be concerned. Among them, delamination due to the high stress is an important issue since its serious effect on the strength and stiffness of the composite structure.

Method: In this investigation, a piezoelectric layer is embedded into the host structure to form a sandwich composite structure. The piezoelectric layer is subjected to an electric voltage, yielding the bending effect on the sandwich composite structure. A theoretical model based on the Euler beam theory and interfacial continuity is presented to determine the stresses of the sandwich composite beam caused by the piezoelectric layer.

Results: The influences of the embedded depth and Young's modulus of the piezoelectric layer on the stress distribution of the sandwich composite beam are investigated through a parametric study. The analytical solutions are verified by the finite element method. Good agreement is achieved between the present approach and the finite element method.

Conclusions: Numerical analysis indicates that the maximum tensile stresses in the top and bottom layers are decreasing with the increase of the embedded depth, while the maximum compressive stress in the lead zirconate titanate layer is increasing with the increase of the embedded depth. Both the top and bottom layers are subjected to tensile stress and increasing with the increase of the Young's modulus ratio, while the piezoelectric layer is subjected to compressive stress and increasing with the increase of the Young's modulus ratio.