Abstract (EN):
The remarkable damping over a broad temperature range and thermal
insulation properties of cork make it a suitable material to be applied on integrated
and surface damping treatments in sandwich structures, improving its dynamic behavior.
Experimental analysis and numerical modeling of sandwich structures with cork
compound layers is therefore essential for a better understanding of the cork compound
influence on the dynamic properties of a layered structure. In this article, an
evaluation study on the dynamic properties of a set of sandwich plates with cork compound
cores inside two aluminium faces is performed. For this purpose, three test
samples were assembled following the described configuration, using cork compounds
with different properties (density, granulometry and thickness). To numerically
simulate these layered plates, a partial layerwise plate finite element (FE), with a
multilayer configuration, was developed and integrated in a MATLAB FE code.
The constitutive relation of the cork compounds is included in the FE model by
using the material complex modulus in a direct frequency analysis procedure. For
the different cork compounds hereby considered, the extensional complex modulus
was previously identified by using a specific experimental methodology which simulates
a semidefinite two degrees of freedom system, where the cork compound test sample
represents the complex stiffness. From the complex modulus data, both
extensional storage modulus and loss factor of the cork compound were obtained.
The experimental evaluation of the dynamic properties of the sandwich plates was
performed carrying out an experimental modal analysis on each test specimen, being
measured a set of frequency response functions (FRFs). Additionally, the developed
layerwise plate element was validated through the comparison between the measured
driving point FRFs and the FE method predicted ones.
Language:
English
Type (Professor's evaluation):
Scientific
Contact:
jdr@fe.up.pt (J. Dias Rodrigues)