Development of a numerical model for the damage identification on composite plate structures

This paper deals with a numerical technique for the identification of damag e on laminated structures. The numerical model is based on a first-order sh ear deformation finite element. When the structure undergoes some kind of d amage, its stiffness is reduced, changing the dynamic response. By consider ing the sensitivities of the orthogonality conditions of the mode shapes, a n algorithm is formulated, which calculates a damage parameter in each fini te element. The damage parameter is directly related to the stiffness reduc tion of the damaged finite element. Only the mechanical properties of the l ayers of the undamaged plate and the natural frequencies and mode shapes of the damaged plate are required. The proposed numerical model allows the id entification of multiple damage and does not require the knowledge of the p robable damaged areas. The algorithm is applied to a laminated rectangular- plate and its efficiency is demonstrated through several damage simulations . (C) 1999 Elsevier Science Ltd. All rights reserved.