A higher order theory for modeling composite laminates with induced strain actuators

A refined higher order laminate theory is developed to analyze smart materials, surface bonded or embedded, in composite laminates. The analysis uses a refined displacement field which accounts for transverse shear stresses through the thickness. All boundary conditions are satisfied at the free surfaces. Non-linearities are introduced through the strain dependent piezoelectric coupling coefficients and the assumed strain distribution through the thickness. The analysis is implemented using the finite element method. The procedure is computationally efficient and allows for a detailed investigation of both the local and global effects due to the presence of actuators. The finite element model is shown to agree well with published experimental results. Numerical examples are presented for composite laminates of various thicknesses and the results are compared with those obtained using classical laminate theory. The refined theory captures important higher order effects which are not modeled by the classical laminate theory, resulting in significant deviations. (C) 1997 Elsevier Science Ltd.