Abstract (EN):
The remarkable damping over a broad temperature range and thermal insulation
properties of cork make it an excellent 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 paper 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, with a multilayer configuration, was
developed and integrated in a MATLAB finite element code. The dynamic properties of the cork
compounds are 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 degree 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 mobility FRF functions. Additionally,
the developed layerwise plate element was validated through the comparison between
the measured driving point FRFs and the FEM predicted ones.
Language:
Portuguese
Type (Professor's evaluation):
Scientific
Contact:
jdr@fe.up.pt