Elastic characterization of orthotropic plates of any shape via static testing

Abstract

The paper presents an inverse procedure for identifying elastic properties of isotropic or orthotropic materials from the full-field measurement of the surface displacements of plates under flexural loading configurations. The procedure is based on a numerical-experimental optimisation process which minimizes an error function defined by subtracting the experimental data from the outputs of the numerical analysis. In each iteration the optimisation process updates the values of the elastic constants in a finite element model of the specimen used in the experimental tests. The unknown parameters are simultaneously identified by a single test and without damaging the structural integrity of the specimen. The possibility of using the methodology for characterizing any-shaped plates was investigated. The applicability and the robustness of the procedure were carried out on aluminum and unidirectional Graphite/PEEK laminate specimens. Phase-shifting speckle interferometry was employed to detect the out-of-plane displacement field of a portion of the observed surface of the specimen.

Elastic characterization of wood by Resonant Ultrasound Spectroscopy (RUS): a comprehensive study

“…Ideally, using only one sample is preferable and allows studying the natural variability. In this context, quasi-static measurements on a single sample of wood have been taken (Bruno and Poggialini 2005;Bruno et al 2008;Majano-Majano et al 2012;Seichepine 1980;Vorobyev et al 2016). This method can be accurate for determining the Young's moduli and some of the Poisson's ratios, but is not so suitable for the determination of the shear moduli on a heterogenous material like wood, due mainly to a non-homogeneous stress field, and it is time-consuming (Hassel et al 2009).…”

Techniques for Identification of Bending and Extensional Elastic Stiffness Matrices on Thin Composite Material Plates Based on Virtual Field Method (VFM): Theoretical and Numerical Aspects

“…The difference among the identification techniques based on these iterative procedures is basically in the way as the optimization problem is formulated, for example, the type of adopted search method to find the minimal, the boundary conditions, the geometric characteristics of the samples, the type of anisotropy of the test material, the type of experimental devices, and the numerical method used to compute the mode shapes (or operational modes) with their respective frequencies (Deobald & Gibson, 1988;Pedersen & Frederiksen, 1992;Lai & Lau, 1993;Ayorinde & Gibson, 1995;Rikards & Chate, 1998;Ayorinde & Yu, 1999Rikards et al, 1999;Bledzki et al, 1999;Hwang & Chang, 2000;Araujo et al, 2000;Chakraborty & Mukhopadhyay, 2000;Rikards et al, 2001;Lauwagie et al, 2003;Lauwagie et al, 2004;Lee & Kam, 2006;Cugnoni et al, 2007;Bruno et al, 2008;Diveyev & Butiter, 2008a, 2008b. In works that do not use iterative process, natural frequencies and mode shapes, or operational frequencies and modes, are input data of an algorithm based on the differential equation that governs the transversal vibration of sample in a specific direction and under specific boundary conditions (Gibson, 2000;Alfano & Pagnotta, 2007).…”

Assessment of Elastic Properties of Isotropic Plates by Dynamic Tests

“…In Table 2, moreover, the values of the elastic constants obtained for the square plate are compared with those obtained for the same plate using the procedures reported in Alfano and Pagnotta, 6–8 and the procedures described in Bruno et al 11 In the last case, an interferometric static method based on the measurement of the superficial displacement field of a specimen under flexural load was carried out. It can be seen that the agreement is excellent.…”