Modeling of adaptive composites including debonding

Debonding of piezoelectric actuators for use in composite structures can result in significant changes to the static and dynamic response. This important issue is studied in the current work. The refined higher order theory for composite laminates with embedded/surface bonded piezoelectric sensors and actuators is extended to incorporate debonding of transducers by partitioning the laminate into debonded and nondebonded regions. The stress free boundary conditions at the free surfaces are satisfied in the analytical formulation. Continuity conditions between the debonded and the nondebonded regions, which are nontrivial for the higher order theory, are formulated and implemented using a penalty approach in the finite element model. The computational model is efficient and correlation with experimental results is very good. Numerical results are presented which indicate significant changes in the natural frequencies and mode shapes due to debonded transducers. (C) 1998 Elsevier Science Ltd. All rights reserved.