Estimation of elastic moduli in olive twig by inversion of vibrational data.

The characteristics parameters of olive tree have been evaluated by inversion of vibrational data. This paper presents a combined numerical/experimental method which allows determination of the two transverse shear moduli in addition to the four in-plane moduli of a thick orthotropic plate of olive tree . E' stata adottata una tecnica non distruttiva basata su una sollecitazione ad impatto, procurata da un martello strumentato, e l'analisi della risposta dinamica del sistema. The olive tree plate response is natural frequencies of flexural vibration. The frequencies are measured by the impulse technique. In the numerical model for solution of the thick plate vibration problem, the Rayleigh-Ritz procedure is combined with a higher-order plate theory. Optimal parameter values are obtained by minimising the difference between theoretical model predictions and experimental data. This difference is formulated in terms of a Weighted least squares objective function. Approximate linearization schemes are used to asses the parameter uncertainty. An example is presented that shows the excellent agreement between measured and calculated frequencies that can be obtained. It is found that for moderately thick plates the reliability of the estimated values of the transverse shear moduli is good.