IDENTIFICATION OF MATERIAL PROPERTIES OF COMPOSITE PLATE SPECIMENS

An indirect identification technique to predict the mechanical propert ies of composite plate specimens is presented. This technique makes us e of experimental eigenfrequencies, the corresponding numerical eigenv alue evaluation, sensitivity analysis and optimization. The laminate a nalysis is formulated in terms of non-dimensional material parameters and the discrete model is based on the linear shear deformation theory of Mindlin. The constrained minimization of an error functional expre ssing the difference between measured higher frequencies of a plate sp ecimen and the corresponding numerical ones is then carried out to fin d the desired optimum parameters. The required sensitivities with resp ect to changes in the non-dimensional material parameters have the opt ion of being evaluated analytically, semi-analytically or alternativel y by finite difference. Results which show the validation of the sensi tivities and the limitations of the model to predict the required quan tities and its range of application and accuracy are demonstrated thro ugh test cases.