Identification of material properties of composite plate specimens

Abstract An indirect identification technique to predict the mechanical properties of composite plate specimens is presented. This technique makes use of experimental eigenfrequencies, the corresponding numerical eigenvalue evaluation, sensitivity analysis and optimization. The laminate analysis 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 expressing the difference between measured higher frequencies of a plate specimen and the corresponding numerical ones is then carried out to find the desired optimum parameters. The required sensitivities with respect to changes in the non-dimensional material parameters have the option of being evaluated analytically, semi-analytically or alternatively by finite difference. Results which show the validation of the sensitivities and the limitations of the model to predict the required quantities and its range of application and accuracy are demonstrated through test cases.