Identification of elastic properties of laminates based on experiment design

A numerical-experimental method for identification of elastic properties of laminated composites from the experimental results is developed. It is pro posed to use the method of experiment design and the response surface appro ach to solve the identification (inverse) problems. The response surface ap proximations are obtained by using the information on the behavior of a str ucture in the reference points of the experiment design. The finite element modeling of the structure is performed only in the reference points. There fore, a significant reduction (about 50-100 times) in calculations of the i dentification functional can be achieved in comparison with the conventiona l methods of minimization. The functional to be minimized describes the dif ference between the measured and numerically calculated eigenfrequencies of structure. By minimizing the functional the identification parameters are obtained. It was shown that identification functional is convex if the stif fness matrix linearly depends on unknown parameters. The method is employed to identify the elastic properties of cross-ply laminates from the measure d eigenfrequencies of composite plates. (C) 2001 Elsevier Science Ltd. All rights reserved.