NEWS ED EVENTI

Autori: C.Boursier Niutta, A.Tridello, G.Belingardi*, D.S.Paolino 
Rivista: Composite Structures   
Anno di Pubblicazione: 2021
Volume:    262
Pagine:    1-10
Abstract:
An innovative experimental methodology for the nondestructive assessment of local elastic properties of
composite materials is proposed in this paper. A local region of rectangular shape is isolated on the
investigated laminate with a proper clamping system. The first resonant frequency of the retained region
with clamped boundaries is determined through the Impulse Excitation Technique. In order to take into
account the anisotropy of the composite laminate, values of the resonant frequency are measured after
rotating the clamping system with respect to the composite plate. The material constants are finally obtained
from the measured frequencies through an inverse optimization algorithm based on Finite Element analysis.
The proposed methodology is validated on a unidirectional composite plate with known elastic properties.
Boundaries of the investigated region are clamped by pressing two rectangular frames to the plate through a
testing machine, thus localizing the measure of the resonant frequencies. The first resonant frequency is
measured at different angles (0°, 30°, 60° and 90°) between fibers direction and main axis of the rectangular
region. Dynamic elastic properties are finally assessed through the proposed inverse optimization algorithm.
The small differences between the nominal and the estimated mechanical properties prove the effectiveness
of the proposed methodology.