Determination of elastic constants of materials by vibration testing

Mechanical properties of nanocomposite laminated structure and its sensibility to modal analysis procedure

“…The optimization is a zero-order approach method, offered as a tool of the FE commercial code, and following the Hwang procedure (Hwang and Chang, 2000;Hwang et al, 2009). The state variables ξ n are related to the difference between FE, !…”

“…The traditional Hammer Test was performed and results were compared. Batista (2005) also used the method proposed by Hwang and Chang (2000), the method works quite well for isotropic and orthotropic plates. However, for angle ply laminates, due to the complexities of mode shapes some constants are not well identified.…”

Sensitivity Analysis of a CPAM Inverse Algorithm for Composite Laminates Characterization

“…In order to validate the FEM modeling, an aluminum plate has been considered and its first six natural frequencies have been compared with those obtained by Rayleigh-Ritz method presented by Deobald and Gibson [9]. Hwang and Chang [8] have extracted them again to validate their FEM modeling in ANSYS software. Dimensions of the considered square aluminum plate are 25.4 cm × 25.4 cm × 0.316 cm, density is 2.77 gr/cm 3 , Young's modulus is 72.4 GPa, shear modulus is 28 GPa, and Poisson's ratio is 0.33.…”

“…Then they succeeded to realize the high dependence of circumferential wave pattern of vibrational mode and in-plane shear modulus on the natural frequencies of cylindrical shells. To simplify the modeling process and reduce the complexity of numerical modeling, Hwang and Chang [8] used an FEM model with an optimization process to determine just elastic constants of thin and thick composite laminates and also aluminum plates. Deobald and Gibson [9] determined four independent elastic constants of thin orthotropic plates.…”

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).…”